The Frontal lobes - Mahidol University

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415703 Cognitive Neuropsychology 

Week 6: 

The Frontal lobes 

Naiphinich Kotchabhakdi, Ph.D. 

Director, Salaya Stem Cell R & D Project, 

Research Center for Neuroscience, 

Institute of Molecular Biosciences, 

Mahidol University Salaya Campus, 

999 Phutthamonthol 4 Road, Salaya, Phutthamonthol, 

Nakornpathom 73170 Thailand 

Email: scnkc@mahidol.ac.th or naiphinich@gmail.com 

Web: www.neuroscience.mahidol.ac.th 

Main Objectives: 

1. The Frontal lobes and their functions 

2. The Motor System 

3. Motor Cortical Organization in the Frontal Lobe 

4. The Prefrontal cortex 

5. The Frontal lobes and higher or executive brain 

functions 

6. Deep brain structures in Frontal lobe, e.g., 

Limbic brain structures and their functions 

7. Neuropsychology of the Frontal lobes and 

executive brain function disorders. 

The Frontal lobe is an area in the brain of humans and other 

mammals, located at the front of each cerebral hemisphere and positioned 

anterior to (in front of) the parietal lobes and superior and anterior to the 

temporal lobes (i.e. directly behind the forehead or "temple"). It is 

separated from the parietal lobe by the post‐central gyrus primary motor 

cortex, which controls voluntary movements of specific body parts 

associated with the precentral gyrus posteriorly, inferiorly by lateral 

sulcus[slyvian] which separates it from the temporal lobe, superiorly by the 

superior margin of the hemisphere and anteriorly by the frontal pole. 

The frontal lobe contains most of the dopamine‐sensitive neurons in the 

cerebral cortex. The dopamine system is associated with reward, attention, 

short‐term term memory tasks, planning, and drive. Dopamine tends to limit and 

select sensory information arriving from the thalamus to the fore‐brain. A 

report from the National Institute of Mental Health says a gene variant that 

reduces dopamine activity in the prefrontal cortex is related to poorer 

performance and inefficient functioning of that brain region during working 

memory tasks, and to slightly increased risk for schizophrenia. 

Frontal lobe Anatomy 

On the lateral surface of the human brain, the central sulcus separates the frontal lobe from 

the parietal lobe. The lateral sulcus separates the frontal lobe from the temporal lobe. 

The frontal lobe can be divided into a lateral, polar, orbital (above the orbit; also called basal 

or ventral), and medial part. Each of these parts consists of particular gyri: 

∆ Lateral part: Precentral gyrus, lateral part of the superior frontal gyrus, middle frontal 

gyrus, inferior frontal gyrus. 

∆ Polar part: Transverse frontopolar gyri, frontomarginal gyrus. 

∆ Orbital part: Lateral orbital gyrus, anterior orbital gyrus, posterior orbital gyrus, medial 

orbital gyrus, gyrus rectus. 

∆ Medial part: Medial part of the superior frontal gyrus, cingulate gyrus. 

The gyri are separated by sulci. E.g., the precentral gyrus is in front of the central sulcus, and 

behind the precentral sulcus. The superior and middle frontal gyri are divided by the 

superior frontal sulcus. The middle and inferior frontal gyri are divided by the inferior frontal 

sulcus. 

In humans, the frontal lobe reaches full maturity around only after the 20s, marking the 

cognitive maturity associated with adulthood. 

Dr. Arthur Toga, a UCLA professor of neurology, found increased myelin in the frontal lobe 

white matter of young adults compared to that of teens. A typical onset of schizophrenia in 

early adult years correlates with poorly myelinated and thus inefficient connections 

between cells in the fore‐brain 

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Functional areas in the frontal lobes 

The motor system is the part of the central nervous system that is involved with 

movement. It consists of the pyramidal and extrapyramidal system. 

The motor pathway also called pyramidal tract or the corticospinal tract start in the motor 

center of the cerebral cortex. 

There are upper and lower motor neurons in the corticospinal tract. 

The motor impulses originates in the Giant pyramidal cells or Betz cells of the motor area i.e. 

precentral gyrus of cerebral cortex. These are the upper motor neurons (UMN) of the 

corticospinal tract. The axons of these cells pass in the depth of the cerebral cortex to the 

Corona radiata and then to the Internal Capsule passing through the posterior branch of 

internal capsule and continue to descend in the Midbrain and the Medulla Oblongata. In 

the lower part of Medulla oblongata 80 to 85% of these fibers decussate (pass to the 

opposite side) and descend in the White matter of the Lateral funiculus of the spinal cord 

on the opposite side. The remaining 15 to 20% pass to the same side. Fibers for the 

extremities (limbs) pass 100% to the opposite side. The fibers of the corticospinal tract 

terminate at different levels in the Anterior horn of the Grey matter of the spinal cord. 

Here the Lower Motor Neurons (LMN) of the corticospinal cord are located. Peripheral motor 

nerves carry the motor impulses from the anterior horn to the voluntary muscles. 

Pyramidal motor system: 

Corticospinal tracts 

tracts is a collection of 

axons that travel between the cerebral cortex 

of the brain and the spinal cord. 

The corticospinal tract mostly contains motor axons. 

It actually consists of two separate tracts in the 

spinal cord: the lateral corticospinal tract and the 

anterior corticospinal tract. 

An understanding of these tracts leads to an 

understanding of why for the most part, one side of 

the body is controlled by the opposite side of the 

brain. 

The corticobulbar tract is also considered to be a 

pyramidal tract, though it carries signals to motor 

neurons of the cranial nerve nuclei, rather than the 

spinal cord. 

The neurons of the corticospinal tracts are referred 

to as pyramidal neurons. The name comes from the 

shape of the corticospinal tracts, which somewhat 

resemble pyramids as they pass through the 

medulla. 

The corticospinal tract is concerned specifically with 

discrete voluntary skilled movements, especially of 

the distal parts of the limbs. (Sometimes called 

"fractionated" movements) 

The motor pathway 

The corticospinal tract originates from pyramidal cells in layer V of the 

cerebral cortex. 

About half of its fibres arise from the primary motor cortex. Other 

contributions come from the supplementary motor area, premotor 

cortex, somatosensory cortex, parietal lobe, and cingulate gyrus. The 

average fiber diameter is in the region of 10μm; around 3% of fibres are 

extra‐large (20μm) and arise from Betz cells, mostly in the leg area of the 

primary motor cortex. 

Upper motor neurons 

Upper motor neurons 

The neuronal cell bodies in the motor cortex, together with their axons 

that travel down through the brain stem and spinal cord are commonly 

referred to as upper motor neurons. It should be noted however, that 

they do not project to muscles, and thus the term 'motor neuron' is 

somewhat misleading. 

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Betz ells 

Anatomy of the motor cortex 

The motor cortex can be divided into four main parts: 

∆ the primary motor cortex (or M1, Broadman area #4), 

responsible for generating the neural impulses controlling 

execution of movement 

and the secondary motor cortices, including 

∆ the posterior parietal cortex, responsible for transforming 

visual information into motor commands 

∆ the premotor cortex, (Broadman areas #6, 8, 9,10) 

responsible for motor guidance of movement and control of 

proximal and trunk muscles of the body 

∆ and the supplementary motor area (or SMA), responsible 

for planning and coordination of complex movements such 

as those requiring two hands. 

Other brain regions outside the cortex are also of great 

importance to motor function, most notably the cerebellum and 

subcortical motor nuclei. 

The primary motor cortex (or M1) is a brain 

region that in humans is located in the posterior portion 

of the frontal lobe. It works in association with pre‐motor 

areas to plan and execute movements. M1 contains large 

neurons known as Betz cells which send long axons down 

the spinal cord to synapse onto alpha motor neurons 

which connect to the muscles. Pre‐motor areas are 

involved in planning actions (in concert with the basal 

ganglia) and refining movements based upon sensory 

input (this requires the cerebellum). 

Location of the Primary Motor Cortex (M1) 

The human primary motor cortex is located in the dorsal part of the precentral gyrus and the 

anterior bank of the central sulcus. The precentral gyrus is anterior to the postcentral gyrus from 

which it is separated by the central sulcus. Its anterior border is the precentral sulcus, while inferiorly 

it borders to the lateral fissure (Sylvian fissure). Medially, it is contiguous with the paracentral lobule. 

This area can also be identified by Brodmann area number 4. 

Layers of the Primary Motor Cortex (M1) 

The internal pyramidal layer (layer V) of the precentral cortex contains giant (70‐100 micrometers) 

pyramidal neurons (a.k.a. Betz cells), which send long axons to the contralateral motor nuclei of the 

cranial nerves and to the lower motor neurons in the ventral horn of the spinal cord. These axons 

form the corticospinal tract. The Betz cells' along with their long axons are referred to as the upper 

motor neuron (UMN). 

"Homunculus" " or "Little Man" 

There is a broadly somatotopic representation of the different body parts in the primary motor 

cortex in an arrangement called a motor homunculus (Latin: little man). The leg area is located close 

to the midline, and the head and face area located laterally on the convex side of the cerebral 

hemisphere (motor homunculus). The arm and hand motor area is the largest, and occupies the part 

of precentral gyrus, between the leg and face area. In humans, the lateral area of the primary motor 

cortex is arranged from top to bottom in areas that correspond to the buttocks, torso, shoulder, 

elbow, wrist, fingers, thumb, eyelids, lips and jaw. Interior sections of the motor area folding into the 

medial longitudinal fissure correspond with the legs. 

These areas are not proportional to their size in the body with the lips, face parts and hands enjoying 

particularly large areas. Following amputation or paralysis, motor areas can shift to adopt new parts 

of the body 

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The Modern Era: Neuropsychology Syndrome 

Analysis, fMRI Studies, Clinical Neuropsychology 

Tests & Clinical Practice 

Two representational areas 

In primates, the primary motor cortex is unusual in having in its anterior and posterior 

areas two representations of the digits and wrist. ] The posterior areas can be activated by 

attention without any sensory feedback and has been suggested to be important for 

initiation of movements, while the anterior areas is dependent on sensory feedback. It 

can also be activated by imaginary finger movements and listening to speech done 

without actual movements. This anterior representation area has been suggested to be 

important executing movements involving complex sensoriomotor interactions. 

Pathway 

As the motor axons travel down through the cerebral white matter, they move closer 

together and form part of the posterior limb of the internal capsule. 

They continue down into the brainstem, where some of them, after crossing over to the 

contralateral side, distribute to the cranial nerve motor nuclei. (Note: a few motor fibers 

synapse with lower motor neurons on the same side of the brainstem). 

After crossing over to the contralateral side in the medulla oblongata (pyramidal 

decussation), the axons travel down the spinal cord as the lateral corticospinal tract. 

Fibers that do not cross over in the brainstem travel down the separate ventral 

corticospinal tract and most of them cross over to the contralateral side in the spinal cord, 

shortly before reaching the lower motor neurons. 

The primary motor cortex receive thalamic input from the Ventral lateral nucleus of the 

Thalamus. 

Blood supply 

Branches of the middle cerebral artery provide most of 

the arterial blood supply for the primary motor cortex. 

The medial aspect (leg areas) is supplied by branches of 

the anterior cerebral artery. 

Neural input from the thalamus 

The primary motor cortex receive thalamic input from 

the Ventral lateral nucleus of the Thalamus. 

Pathology 

Lesions of the precentral gyrus result in paralysis of the 

contralateral side of the body (facial palsy, arm‐/leg 

monoparesis, hemiparesis) ‐ see upper motor neuron. 

The premotor cortex is an area of motor 

cortex lying within the frontal lobe of the brain. It 

extends 3mm anterior to the primary motor cortex, 

near the Sylvian fissure, before narrowing to 

approximately 1mm near the medial longitudinal 

fissure, which serves as the posterior border for the 

prefrontal cortex. The premotor cortex is largely 

equivalent to Brodmann area 6. Activity within this 

region is critical to the sensory guidance of 

movement and control of proximal and trunk muscles 

of the body. 

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The premotor cortex is dysgranular (a transition between the agranular motor cortex and the granular 

eulaminate frontal cortex), which means that there is only a faint granular lamina IV. This corresponds to Brodmann 

area 6, with the exception that the medial surface of this area is the site of the accessory motor cortex (also known as 

the supplementary motor area, or SMA). 

Afferents 

Subcortical 

Cortical 

The pre‐motor cortex receives inputs originating from other areas of the cortex, including the inferior and 

superior parietal lobules (from which it receives multimodal sensory information) and the frontal cortex 

(from which it receives information related to attention and motivation) [1] 

Efferents 

Subcortical 

Cortico‐spinal 

The axons of the premotor cortex contribute to the pyramidal bundle 

Striatum 

Axons of the Vth layer contribute to the corticostriate connection ; a massive connection involving almost 

all parts of the cortex 

Thalamus 

The premotor cortex sends axons to the motor thalamus. This comprises a part receiving cerebellar axons 

( nucleus Ventralis Intermedius Vim or VL), a part receiving pallidal axons (nucleus Ventralis oralis VO) and 

a part receiving nigral axons (nucleus Ventralis anterio VA). The Vim is separated into two parts one 

ventrolateral and one mediodorsal VImM. The premotor cortex sends axons electively to VImM and VO 

Central complex 

Subthalamic nucleus 

Cortical 

Physiology 

Mirror neurons are cells located in the premotor cortex, the part of the brain relevant to the planning, selection and 

execution of actions. It is a part of the Cerebral cortex. 

The supplementary 

motor area (SMA) is a part 

of the sensorimotor cerebral 

cortex (perirolandic, i.e. on each 

side of the Rolando or central 

sulcus). It was included, on purely 

cytoarchitectonic arguments, in 

area 6 of Brodmann and the 

Vogts. It is located on the medial 

face of the hemisphere, just in 

front of primary motor cortex. This 

is an element that appeared late in 

evolution, in monkeys, linked to 

the appearance of a true medial 

pallidum. 

Supplementary Motor Area (SMA) 

It has been found that the SMA is likely made up of two anatomically and functionally distinct parts, and was divided into the SMA proper 

(or: caudal SMA) and the pre‐SMA (or: rostral SMA). In primates, the SMA proper is analogous to area F3, whereas the pre‐SMA is 

analogous to area F6. 

In monkeys it is a part of the dysgranular cortex. This means an intermediate differentiation between the more posterior agranular motor 

cortex and the more anterior granular eulaminate frontal cortex. 

Function of SMA 

The SMA is implicated in the planning of motor actions and bimanual control. In contrast to the premotor cortex, the SMA has been 

implicated in actions that are under internal control, such as the performance of a sequence of movements from memory (as opposed to 

movements guided by a visual cue). 

Pre‐SMA is involved in acquiring new sequences. There is more activity in these neurons when the sequence is new, compared to when it 

has been already learned. In contrast, SMA neurons are more active when performing a sequence already learned than one still being 

learned. This suggests that the SMA may be more involved in retrieving the sequence. SMA neurons are more active when the task 

requires the arrangement of multiple movements in the correct sequence and correct temporal order. For example, some SMA neurons 

"prefer" a specific order of movements to be performed. Other SMA neurons fire more for the preparation of a specific rank order. For 

example, a neuron can fire more when a monkey is preparing to initiate the third movement, irrespective of the sequence of the three 

movements. 

SMA and Pre‐SMA can be distinguished by various physiological techniques that delineate two different areas rostrocaudally. Field and 

unitary responses to electrical stimulation of the primary motor cortex were distinct in the caudal part, but minimal or absent in the rostral 

part. Intracortical microstimulation readily evoked limb or orofacial movements in the caudal part, but only infrequently in the rostral part. 

Neuronal responses to visual stimuli prevailed in the rostral part, but somatosensory responses were rare. The opposite was true in the 

caudal part. The rostral part, roughly corresponding to area 6a beta, was operationally defined as the presupplementary motor area (pre‐ 

SMA). The caudal part was redefined as the SMA proper. Single‐cell activity in the pre‐SMA was quantitatively compared with that in the 

SMA proper in relation to a trained motor task. Phasic responses to visual cue signals indicating the direction of forthcoming arm‐reaching 

movement were more abundant in the pre‐SMA. Activity changes during the preparatory period, which lasted until the occurrence of the 

trigger signal for the reaching movement, were more frequent in the pre‐SMA. Phasic, movement‐related activity was more frequent in the 

SMA, and its onset was often time locked to the movement onset. In the pre‐SMA, the occurrences of response time locked to the 

movement‐trigger signal were more frequent than in the SMA. Among neurons in both areas, directional selectivity was found in all the 

cue, preparatory, and movement‐related responses. 

Recent considerations of the diverse activities in which the SMA and pre‐SMA play a role suggest existing theories may not fully capture 

the fundamental functions of these regions. 

The SMA is the most dorsal aspect of BA6 (extending medially towards the cingulate gyrus), the ventral aspect which extends down to the 

sylvian fissure is the secondary motor cortex (also BA6) 

Decussation and synapses 

Some of the neuronal cell bodies in the motor cortex send long axons to the motor 

cranial nerve nuclei mainly of the contralateral side of the midbrain (corticomesencephalic 

tract), pons (Corticopontine tract), and medulla oblongata (cortico‐bulbar 

tract), decussating just before they reach their target nuclei. 

These are called geniculate fibers. Many more motor cortex neurons, however, extend 

fibers all the way down to the spinal cord (corticospinal tract). 

► Most of the corticospinal fibers (about 80%) cross over to the contralateral side in the 

medulla oblongata (pyramidal decussation). Those that cross in the medulla oblongata 

travel in the lateral corticospinal tract. 

► 10% enter the lateral corticospinal tract on the same side. 

► The remainder of them (10%) cross over at the level that they exit the spinal cord, and 

these travel in the anterior corticospinal tract. 

Whichever of these two tracts it travels in, a corticospinal axon will synapse with another 

neuron in the ventral horn. This ventral horn neuron is considered a second‐order neuron 

in this pathway, but is not part of the corticospinal tract itself. 

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From cerebral to motor neurons 

The motor axons move closer together as they travel down through the cerebral white 

matter, and form part of the posterior limb of the internal capsule. 

The motor fibers continue down into the brainstem. The bundle of corticospinal axons is 

visible as two column‐like structures ("pyramids") on the ventral surface of medulla 

oblongata ‐ this is where the name pyramidal tract comes from. 

After the decussation, the axons travel down the spinal cord as the lateral corticospinal tract. 

Fibers that do not cross over in the medulla oblongata travel down the separate anterior 

corticospinal tract, and most of them cross over to the contralateral side in the spinal cord, 

shortly before reaching the lower motor neurons. 

Lower motor neurons 

In the spinal cord, the axons of the upper motor neuron connect (most of them via 

interneurons, but to a lesser extent also via direct synapses) with the lower motor neurons, 

located in the ventral horn of the spinal cord. 

In the brainstem, the lower motor neurons are located in the motor cranial nerve nuclei 

(oculomotor, trochlear, motor nucleus of the trigeminal nerve, abducens, facial, accessory, 

hypoglossal). The lower motor neuron axons leave the brain stem via motor cranial nerves 

and the spinal cord via anterior roots of the spinal nerves respectively, end‐up at the 

neuromuscular plate and provide motor innervation for voluntary muscles. 

The Principles of Motor Controls of Movements: 

1. The central nervous system (CNS) has to choose the right group 

of muscles by selecting specific pathways. 

2. The CNS must give the right amount of excitatory or inhibitory 

inputs (“Command”) to specific motoneuron pools 

3. The excitatory and inhibitory commands must be regulated 

“Spatially” and “Temporally”. 

4. The CNS must regulate the following parameters: 

‐ force 

‐displacement (distance) 

‐ velocity, acceleration or deceleration 

The extrapyramidal system is a neural network located in the 

brain that is part of the motor system involved in the coordination of movement. 

The system is called "extrapyramidal" to distinguish it from the tracts of the motor 

cortex that reach their targets by traveling through the "pyramids" of the medulla. 

The pyramidal pathways (corticospinal and some corticobulbar tracts) may directly 

innervate motor neurons of the spinal cord or brainstem (anterior (ventral) horn 

cells or certain cranial nerve nuclei), whereas the extrapyramidal system centers 

around the modulation and regulation (indirect control) of anterior (ventral) horn 

cells. 

Extrapyramidal tracts are chiefly found in the reticular formation of the pons and 

medulla, and target neurons in the spinal cord involved in reflexes, locomotion, 

complex movements, and postural control. These tracts are in turn modulated by 

various parts of the central nervous system, including the nigrostriatal pathway, 

the basal ganglia, the cerebellum, the vestibular nuclei, and different sensory 

areas of the cerebral cortex. All of these regulatory components can be considered 

part of the extrapyramidal system, in that they modulate motor activity without 

directly innervating motor neurons. 

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Corticospinal tract damage 

Damage to the descending motor pathways anywhere 

along the trajectory from the cerebral cortex to the lower 

end of the spinal cord gives rise to a set of symptoms 

called the "upper motor neuron syndrome". A few days 

after the injury to the upper motor neurons a pattern of 

motor signs and symptoms appears, including spasticity, 

the decreased vigor (and increased threshold) of 

superficial reflexes, a loss of the ability to perform fine 

movements, and an extensor plantar response known as 

the Babinski sign. [ 

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Basal ganglion and 

Extrapyramidal 

System 

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The extrapyramidal system can be affected in a number of ways, 

which are revealed in a range of extrapyramidal symptoms (EPS), 

also known as extrapyramidal side‐effects (EPSE), such as akinesia 

(inability to initiate movement) and akathisia (inability to remain 

motionless). 

Extrapyramidal symptoms (EPS) are various movement disorders 

such as acute dystonic reactions, pseudoparkinsonism, or akathisia 

suffered as a result of taking dopamine antagonists, usually 

antipsychotic (neuroleptic) drugs, which are often used to control 

psychosis. 

The Simpson‐Angus Scale (SAS) and the Barnes Akathisia Rating Scale 

(BARS) are used to measure extrapyramidal symptoms 

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The frontal eye fields (FEF) is a region located in the premotor cortex, 

which is part of the frontal cortex of the primate brain. 

Function 

The cortical area called frontal eye fields (FEF) plays an important role in the control of 

visual attention and eye movements. Electrical stimulation in the FEF elicits saccadic eye 

movements. The FEF have a topographic structure and represents saccade targets in 

retinotopic coordinates. 

The frontal eye field is reported to be activated during the initiation of eye movements, 

such as voluntary saccades and pursuit eye movements. There is also evidence that it 

plays a role in purely sensory processing and that it belongs to a “fast brain” system 

through a superior colliculus – medial dorsal nucleus –FEF ascending pathway.In 

humans, its earliest activations in regard to visual stimuli occur at 45 ms with activations 

related to changes in visual stimuli within 45–60 ms (these are comparable with 

response times in the primary visual cortex). This fast brain pathway also provides 

auditory input at even shorter times starting at 24 ms and being affected by auditory 

characteristics at 30–60 ms. The FEF constitutes together with the supplementary eye 

fields (SEF), the intraparietal sulcus (IPS) and the superior colliculus (SC) one of the most 

important brain areas involved in the generation and control of eye movements, 

particularly in the direction contralateral to the frontal eye fields' location. 

Brain: Frontal eye fields 

Frontal eye fields is roughly located 

between regions #4, #6, and #8 

Brodmann area 8, or BA8, is part of the 

frontal cortex in the human brain. Situated just 

anterior to the premotor cortex (BA6), it includes the 

frontal eye fields (so‐named because they are 

believed to play an important role in the control of 

eye movements). Damage to this area, by stroke, 

trauma or infection, causes tonic deviation of the 

eyes towards the side of the injury. This finding 

occurs during the first few hours of an acute event 

such as cerebrovascular infarct (stroke) or 

hemorrhage (bleeding). 

Distinctive features (Brodmann‐1905): compared to Brodmann area 6‐ 

1909, area 8 has a diffuse but clearly present internal granular layer (IV); 

sublayer 3b of the external pyramidal layer (III) has densely distributed 

medium sized pyramidal cells; the internal pyramidal layer (V) has larger 

ganglion cells densely distributed with some granule cells interspersed; the 

external granular layer (II) is denser and broader; cell layers are more 

distinct; the abundance of cells is somewhat greater. 

Other Functions 

The area is involved in the management of uncertainty. A functional 

magnetic resonance imaging study demonstrated that brodmann area 8 

activation occurs when test subjects experience uncertainty, and that with 

increasing uncertainty there is increasing activation. 

An alternative interpretation is that this activation in frontal cortex encodes 

hope, a higher‐order expectation positively correlated with uncertainty. 

Brain: Brodmann area 8 

Supplementary eye fields (SEF) are areas on the 

dorsal‐medial surface of frontal lobe of the primate brain 

that are involved in planning and control of saccadic eye 

movements. The SEF was first characterized by John Schlag 

and colleagues as an area where low intensity electrical 

stimulation can evoke saccades, similar to the more lateral 

frontal eye fields. More recently it was shown that SEF 

stimulation produces coordinated gaze movements of both 

the eyes and head. Neural recordings in the SEF show signals 

related to both vision and saccades somewhat like the 

frontal eye fields and superior colliculus, but currently most 

investigators think that the SEF has a special role in high 

level aspects of saccade control, like complex spatial 

transformations, learned transformations, and executive 

cognitive functions 

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Frontal lobe Executive Functions 

The executive functions of the frontal lobes involve the ability 

to recognize future consequences resulting from current 

actions, to choose between good and bad actions (or better 

and best), override and suppress unacceptable social 

responses, and determine similarities and differences 

between things or events. Therefore, it is involved in higher 

mental functions. 

The frontal lobes also play an important part in retaining 

longer term memories which are not task‐based. These are 

often memories associated with emotions derived from input 

from the brain's limbic system. The frontal lobe modifies those 

emotions to generally fit socially acceptable norms. 

Psychological tests that measure frontal lobe function include 

finger tapping, Wisconsin Card Sorting Task, and measures of 

verbal and figural fluency. 

Comparative Neurobiology: 

Evolutionary Consideration 

COMPARATIVE BRAIN 

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สมองคน 

Frontal lobe Evolution 

For many years, many scientists thought that the frontal 

lobe was disproportionately enlarged in humans 

compared to other primates. They thought that this was 

an important feature of human evolution and was the 

primary reason why human cognition is different from 

that of the other primates. 

However, this view has been challenged by newer 

research. Using magnetic resonance imaging to determine 

the volume of the frontal cortex in humans, all extant ape 

species and several monkey species, Semendeferi et al. 

found that the human frontal cortex was not relatively 

larger than the cortex in the other great apes but was 

relatively larger than the frontal cortex in the lesser apes 

and the monkeys 

The limbic system is also tightly connected to the 

prefrontal cortex. 

Some scientists contend that this connection is 

related to the pleasure obtained from solving problems. To 

cure severe emotional disorders, this connection was 

sometimes surgically severed, a procedure of 

psychosurgery, called a prefrontal lobotomy. Patients who 

underwent this procedure often became passive and 

lacked all motivation. 

There is circumstantial evidence that the limbic 

system also provides a custodial function for the 

maintenance of a healthy conscious state of mind. 

“Psychosurgery” 

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Psychosurgery 

In the early 20th century, a medical treatment for mental illness, 

first developed by Portuguese neurologist Egas Moniz, involved 

damaging the pathways connecting the frontal lobe to the limbic 

system. Frontal lobotomy (sometimes called frontal leucotomy) 

successfully reduced distress but at the cost of often blunting the 

subject's emotions, volition and personality. The indiscriminate use 

of this psychosurgical procedure, combined with its severe side 

effects and dangerous nature, gained it a bad reputation. The 

frontal lobotomy has largely died out as a psychiatric treatment. 

More precise psychosurgical procedures are still used, although 

rarely. They may include anterior capsulotomy (bilateral thermal 

lesions of the anterior limbs of the internal capsule) or the bilateral 

cingulotomy (involving lesions of the anterior cingulate gyri) and 

might be used to treat otherwise untreatable obsessional disorders 

or clinical depression 

Theories of frontal lobe functions can be differentiated into four categories: 

∆ Single‐process theories. Posit "that damage to a single process or system is responsible for a 

number of different dysexecutive symptoms” (Burgess, 2003, p. 309). 

∆ Multi‐process theories. Propose “that the frontal lobe executive system consists of a number of 

components that typically work together in everyday actions [(heterogeneity of function)]“ (Burgess, 

2003, p. 310). 

∆ Construct‐led theories. Assume “that most if not all frontal functions can be explained by one 

construct (homogeneity of function) such as working memory or inhibition” (Stuss, 1999, p. 348; cf. 

Burgess & Simons, 2005). 

∆ Single‐symptom theories. Suggest that a specific dysexecutive symptom (e.g., confabulation) is 

related to the processes and construct of the underlying structures (cf. Burgess & Simons, 2005). 

Stuss (1999) suggests a differentiation into two categories according to homogeneity and 

heterogeneity of function. 

Further theoretical approaches to frontal lobe function include: 

∆ Grafman's managerial knowledge units (MKU) / structured event complex (SEC) approach (cf. Wood 

& Grafman, 2003) 

∆ Miller & Cohen's integrative theory of prefrontal functioning (e.g. Miller & Cohen, 2001) 

∆ Rolls's stimulus‐reward approach and Stuss's anterior attentional functions (Burgess & Simons, 

2005; Burgess, 2003; Burke, 2007). 

It may be highlighted that the theories described above differ in their focus on certain 

processes/systems or construct‐lets. Stuss (1999) remarks that the question of homogeneity (single 

construct) or heterogeneity (multiple processes/systems) of function “may represent a problem of 

semantics and/or incomplete functional analysis rather than an unresolvable dichotomy” (p. 348). 

However, further research will show if a unified theory of frontal lobe function that fully accounts for 

the diversity of functions will be available. 

Damage to the frontal lobes can lead to a variety of results: 

Case Study 

Mr. Phineas Gage 

Published in 

New England 

Journal of Medicine 

in 1860 

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Brodmann’s area is a region of the cerebral cortex defined based on 

its cytoarchitectonics, or organization of cells 

Brodmann areas were originally defined and numbered by the German neurologist 

Korbinian Brodmann basedonthecytoarchitecture organisation of neurons he 

observed in the cerebral cortex using the Nissl stain. Brodmann published his maps 

of cortical areas in humans, monkeys, and other species in 1909, along with many 

other findings and observations regarding the general cell types and laminar 

organization of the mammalian cortex. (The same Brodmann area number in 

different species does not necessarily indicate homologous areas.) 

A more detailed and verifiable cortical map have since been published by Constantin von 

Economo and Georg N. Koskinas which greatly improves the quality of the cytoarchitectonic 

classifications. 

Many of the areas Brodmann defined based solely on their neuronal organization have since 

been correlated closely to diverse cortical functions. For example, Brodmann areas 1, 2 and 

3aretheprimary somatosensory cortex; area4istheprimary motor cortex; area17isthe 

primary visual cortex; and areas 41 and 42 correspond closely to primary auditory cortex. 

Higher order functions of the association cortical areas are also consistently localized to the 

same Brodmann areas by neurophysiological, functional imaging, and other methods (e.g., 

the consistent localization of Broca's speech and language area to the left Brodmann areas 

44 and 45). However, functional imaging can only identify the approximate localization of 

brain activations in terms of Brodmann areas since their actual boundaries in any individual 

brain requires its histological examination. 

Brodmann areas for human & non‐human primates 

Brodmann’s areas 3D 

map: Lateral Surface 

map: Medial Surface 

Brodmann areas for human & non‐human primates 

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Paul Pierre Broca (June 28, 1824 – 

July 9, 1880) was a French physician, 

anatomist, and anthropologist. He was 

born in Sainte-Foy-la-Grande, France. 

He is best known for his research on 

Broca's area, a region of the frontal 

lobe that has been named after him. 

Broca's legacy 

The discovery of Broca's area revolutionized the 

understanding of speech production. New research 

has found that dysfunction in the area may lead to 

other speech disorders such as stuttering and 

apraxia of speech. Recent anatomical 

neuroimaging studies have shown that the pars 

opercularis of Broca's area is anatomically smaller 

in individuals who stutter whereas the pars 

triangularis appears to be normal. 

Speech research 

Broca is most famous for his discovery of the speech production center of the brain 

located in the ventroposterior region of the frontal lobes (now known as Broca's 

area). He arrived at this discovery by studying the brains of aphasic patients. His first 

patient in the Bicêtre Hospital was Leborgne, nicknamed "Tan" due to his inability to 

clearly speak any words other than "tan". 

In 1861, through post‐mortem autopsy, Broca determined that Tan had a lesion 

caused by syphilis in the left cerebral hemisphere. This lesion was determined to 

cover the area of the brain important for speech production. (Although history 

credits this discovery to Broca, it should be noted that another French neurologist, 

Marc acDax, made similar observations o s a generation e earlier.) e ) Today the brains ba sof many 

of Broca's aphasic patients are still preserved in the Musée Dupuytren, and his 

collection of casts in the Musée d'Anatomie Delmas‐Orfila‐Rouvière. 

Patients with damage to Broca's area and/or to neighboring regions of the left 

inferior frontal lobe are often categorized clinically as having Broca's aphasia. This 

type of aphasia, which often involves impairments in speech output, can be 

contrasted with Wernicke's aphasia, named for Karl Wernicke, which is 

characterized by damage to more posterior regions of the left hemisphere (in the 

superior temporal lobe), and by greater impairments in speech comprehension. This 

is an example of a double dissociation, an important tool used by 

neuropsychologists to investigate brain function. 

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Paul Broca (1824-1880) 

Tan’s Brain 

(removed in 1861) 

Now in the Museum of Man, Paris 

Expressive aphasia, known as Broca's aphasia in clinical 

neuropsychology and agrammatic aphasia in cognitive 

neuropsychology, is an aphasia caused by damage to or 

developmental issues in anterior regions of the brain, including (but 

not limited to) the left inferior frontal region known as Broca's area 

(Brodmann area 44 and Brodmann area 45) 

Presentation 

Sufferers of this form of aphasia exhibit the common problem of agrammatism. For them, speech is difficult to initiate, 

non‐fluent, labored, and halting. Similarly, writing is difficult as well. Intonation and stress patterns are deficient. 

Language g is reduced to disjointed words and sentence construction is poor, omitting function words and inflections 

(bound morphemes). A person with expressive aphasia might say "Son ... University ... Smart ... Boy ... Good ... Good ... " 

For example, in the following passage, a Broca's aphasic patient is trying to explain how he came to the hospital for 

dental surgery: 

Yes... ah... Monday... er... Dad and Peter H... (his own name), and Dad.... er... hospital... and ah... Wednesday... 

Wednesday, nine o'clock... and oh... Thursday... ten o'clock, ah doctors... two... an' doctors... and er... teeth... 

yah.[1] 

In extreme cases, patients may be only able to produce a single word. The most famous case of this was Paul Broca's 

patient Leborgne, nicknamed "Tan", after the only syllable he could say. Even in such cases, over-learned and rote-learned 

speech patterns may be retained—for instance, some patients can count from one to ten, but cannot produce the same 

numbers in ordinary conversation. 

While word comprehension is generally preserved, meaning interpretation dependent on syntax and phrase structure is 

substantially impaired. This can be demonstrated by using phrases with unusual structures. A typical Broca's aphasic 

patient will misinterpret "the dog is bitten by the man" by switching the subject and object. Patients who recover go on to 

say that they knew what they wanted to say but could not express themselves. Residual deficits will often be seen. 

Broca's area is a region of the hominid brain 

with functions linked to speech production. 

The production of language has been linked to the 

Broca’s area since Pierre Paul Broca reported 

impairments in two patients. They had lost the 

ability to speak after injury to the posterior inferior 

frontal gyrus of the brain. Since then, the 

approximate region he identified has become 

known as Broca’s area, and the deficit in language 

production as Broca’s aphasia. Broca’s area is now 

typically defined in terms of the pars opercularis 

and pars triangularis of the inferior frontal gyrus, 

represented in Brodmann’s 

cytoarchitectonic map 

as areas 44 and 45. Studies of chronic aphasia have 

implicated an essential role of Broca’s area in 

various speech and language functions. Further, 

functional MRI studies have also identified 

activation patterns in Broca’s area associated with 

various language tasks. However, slow destruction 

of the Broca's area by brain tumors can leave 

speech relatively intact suggesting its functions can 

shift to nearby areas in the brain. 

Brodmann area 44, , or BA44 

44, is part of the frontal 

cortex in the human brain. Situated just anterior to premotor 

cortex (BA6) and on the lateral surface, inferior to BA9. 

This area is also known as pars opercularis (of the inferior 

frontal gyrus), and it refers to a subdivision of the 

cytoarchitecturally defined frontal region of cerebral cortex. In 

the human it corresponds approximately to the opercular part 

of inferior frontal gyrus (H). Thus, it is bounded caudally by the 

inferior precentral sulcus (H) and rostrally by the anterior 

ascending limb of lateral sulcus (H). It surrounds the diagonal 

sulcus (H). In the depth of the lateral sulcus it borders on the 

insula. Cytoarchitectonically it is bounded caudally and dorsally 

by the agranular frontal area 6, dorsally by the granular frontal 

area 9 and rostrally by the triangular area 45 (Brodmann‐1909). 

Together with left‐hemisphere BA 45, the left hemisphere . BA 

44 comprises Broca's area a region involved in semantic tasks. 

Some data suggest that BA44 is more involved in phonological 

and syntactic processing. Some recent findings also suggest the 

implication of this region in music perception. In 95.5% of righthanders 

and 61.4% of left‐handers, therefore about 90% of the 

clinical population, speech is lateralised in the left hemisphere. 


7/19/2011 NEUROPSYCHIATRY 143 

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Brodmann area 45 (BA45), 

is part of the frontal 

cortex in the human brain. Situated on the lateral surface, 

inferior to BA9 and adjacent to BA46. This area is also known as 

pars triangular (of the inferior frontal gyrus). In the human, it 

occupies the triangular part of inferior frontal gyrus (H) and, surrounding 

the anterior horizontal limb of lateral sulcus (H), a portion of the orbital 

part of inferior frontal gyrus (H). Bounded caudally by the anterior 

ascending limb of lateral sulcus (H), it borders on the insula in the depth 

of the lateral sulcus. Cytoarchitectonically it is bounded caudally by the 

opercular area 44 (BA44), rostrodorsally by the middle frontal area 46 

(BA46) and ventrally by the orbital area 47 (BA47) (Brodmann‐1909). 

Together with BA 44 it comprises Broca's area, a region which is active in 

semantic tasks, such as semantic decision tasks (determining whether a 

word represents an abstract or a concrete entity) and generation tasks 

(generating a verb associated with a noun). 

The precise role of BA45 in semantic tasks remains controversial. For 

some researchers, its role would be to subserve semantic retrieval or 

semantic working memory processes. Under this view, BA44 and BA45 

would together guide recovery of semantic information and evaluate the 

recovered information with regards to the criterion appropriate to a 

given context. A slightly modified account of this view is that activation 

of BA45 is needed only under controlled semantic retrieval, when strong 

stimulus‐stimulus associations are absent. For other researchers, BA45's 

role is not restricted to semantics per se, but to all activities which 

require task‐relevant representations from among competing 

representations. 


Brodmann area 47, , or BA47 

47, is part of 

the frontal cortex in the human brain. Curving from the 

lateral surface of the frontal lobe into the ventral 

(orbital) frontal cortex. It is below areas BA10 and BA45, 

and beside BA11. 

This area is also known as orbital area 47. In the human, 

on the orbital surface it surrounds the caudal portion of 

the orbital sulcus (H) from which it extends laterally into 

the orbital part of inferior frontal gyrus (H). 

Cytoarchitectonically yoac eco cayit is bounded caudally by the 

triangular area 45, medially by the prefrontal area 11 of 

Brodmann‐1909, and rostrally by the frontopolar area 10 

(Brodmann‐1909). 

It incorporates the region that Brodmann identified as 

"Area 12" in the monkey, and therefore, following the 

suggestion of Michael Petrides, some contemporary 

neuroscientists refer to the region as "BA47/12." 

BA47 has been implicated in the processing of syntax 

in spoken and signed languages, and more recently in 

musical syntax. 


The Wernicke's area is classically located as 

the posterior section of the superior temporal gyrus 

(STG) in the left (or dominant) cerebral hemisphere. 

This area encircles the auditory cortex on the Sylvian 

fissure (part of the brain where the temporal lobe 

and parietal lobe meet). This area is 

neuroanatomically described as the posterior part of 

Brodmann area 22. 

However, there is an absence of consistent 

definitions as to its location. Some identify it with 

the unimodal auditory association in the superior 

temporal gyrus anterior to the primary auditory 

cortex. Others include also adjacent parts of the 

heteromodal cortex in BA 39 and BA40 in the 

parietal lobe. 

While previously thought to connect Wernicke's area 

and Broca's area, new research demonstrates that 

the arcuate fasciculus instead connects to posterior 

receptive areas with premotor/motor areas, and not 

to Broca's area 

Wernicke and aphasia 

Wernicke's area is named after Carl Wernicke, a German neurologist and psychiatrist who, in 

1874, hypothesized a link between the left posterior section of the superior temporal gyrus 

and the reflexive mimicking of words and their syllables that associated the sensory and motor 

images of spoken words. He did this on the basis of the location of brain injuries that caused 

aphasia. Receptive aphasia in which such abilities are preserved is now sometimes called 

Wernicke's aphasia. In this condition there is a major impairment of language comprehension, 

while speech retains a natural‐sounding rhythm and a relatively normal syntax. Language as a 

result is largely meaningless (a condition sometimes called fluent or jargon aphasia). 

While neuroimaging and lesion evidence generally support the idea that malfunction of or damage to 

Wernicke's area is common in people with receptive aphasia, this is not always so. Some people may use 

the right hemisphere for language, and isolated damage of Wernicke's area cortex (sparing white matter 

and other areas) may not cause severe receptive aphasia. Even when patients with Wernicke's area lesions 

have comprehension deficits, these are usually not restricted to language processing alone. For example, 

one study found that patients with posterior lesions also had trouble understanding nonverbal sounds like 

animal and machine noises. In fact, for Wernicke's area, the impairments in nonverbal sounds were 

statistically stronger than for verbal sounds. 

Right homologous area 

Research using Transcranial magnetic stimulation suggests that the area corresponding to the Wernicke’s 

area in the non‐dominant cerebral hemisphere has a role in processing and resolution of subordinate 

meanings of ambiguous words—such as (‘‘river’’) when given the ambiguous word (‘‘bank’’). In contrast, 

the Wernicke's area in the dominant hemisphere processes dominant word meanings (‘‘teller’’ given 

‘‘bank’’). 

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The Wernicke-Geschwind model of 

language 

Wernicke created an early neurological model 

of language, that later was revived by Norman 

Geschwind. The model is known as the 

Wernicke‐Geschwind model. 

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Prefrontal 

cortex 

Brodmann area 9, , or BA9, is part of the 

frontal cortex in the human brain. It 

contributes to the dorsolateral prefrontal 

cortex. 

Brodmann area 9 refers to a cytoarchitecturally defined 

portion of the frontal lobe of the guenon (Old world 

monkeys). Brodmann‐1909 regarded it on the whole as 

topographically and cytoarchitecturally homologous to the 

granular frontal area 9 and frontopolar area 10 in the 

human. Distinctive features (Brodmann‐1905): unlike 

Brodmann area 6‐1909, area 9 has a distinct internal 

granular layer (IV); unlike Brodmann area 6 or Brodmann 

area 8‐1909 its internal pyramdal layer (V) is divisible into 

two sublayers, an outer layer 5a of densely distributed 

medium sized ganglion cells that partially merges with 

layer IV, and an inner, clearer, cell‐poor layer 5b; the 

pyramidal cells of sublayer 3b of the external pyramidal 

layer (III) are smaller and sparser in distribution; the 

external granular layer (II) is narrow, with small numbers 

of sparsely distributed granule cells. 


The dorsolateral prefrontal cortex (DL‐PFC or DLPFC), 

according to a more restricted definition, is roughly equivalent to Brodmann areas 9 and 46. 

According to a broader definition DL‐PFC consists of the lateral portions of Brodmann areas 

9 – 12, of areas 45, 46, and the superior part of area 47.These regions mainly receive their 

blood supply from the middle cerebral artery. With respect to neurotransmitter systems, 

there is evidence that dopamine plays a particularly important role in DL‐PFC. 

DL‐PFC is connected to the orbitofrontal cortex, and to a variety of brain areas, which 

include the thalamus, parts of the basal ganglia (the dorsal caudate nucleus), the 

hippocampus, and primary and secondary association areas of neocortex, including 

posterior temporal, parietal, and occipital areas. 

DL‐PFC is the last area, 45th, to develop myelinate in the human cerebrum 

DL‐PFC serves as the highest h cortical area responsible for motor planning, organization, i and 

regulation. It plays an important role in the integration of sensory and mnemonic 

information and the regulation of intellectual function and action. It is also involved in 

working memory. However, DL‐PFC is not exclusively responsible for the executive 

functions. All complex mental activity requires the additional cortical and subcortical 

circuits with which the DL‐PFC is connected. 

Damage to the DL‐PFC can result in the dysexecutive syndrome, [4] which leads to problems 

with affect, social judgement, executive memory, abstract thinking and intentionality. [ 

Lucid dream states 

More recent research has found a connection between the DL‐PFC and lucid dream states 

in which executive function is retained 

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Brodmann area 10, or BA10 

is the 

frontopolar part of the frontal cortex in the human brain. 

BA10 was originally defined in terms of microscopic 

cytoarchitecturic traits in autopsy brains; modern functional 

imaging research cannot directly identify these boundaries 

and the terms anterior prefrontal, rostral prefrontal cortex 

and frontopolar prefrontal cortex are used to refer to the 

area in the most anterior part of the frontal cortex that 

approximates to or principally covers BA10. 

BA10 is the largest cytoarchitectonic area in the human 

brain. It has been described as "one of the least well 

understood dregions of the human brain". Present research 

suggests that it is involved in strategic processes in memory 

retrieval and executive function. During human evolution, 

the functions in this area resulted in its expansion relative to 

the rest of the brain. 

Although this region is extensive in humans, its function is poorly understood. 

Koechlin & Hyafil have proposed that processing of 'cognitive branching' is the 

core function of the frontopolar cortex. Cognitive branching enables a 

previously running task to be maintained in a pending state for subsequent 

retrieval and execution upon completion of the ongoing one. Many of our 

complex behaviors and mental activities require simultaneous engagement of 

multiple tasks, and they suggest the anterior prefrontal cortex may perform a 

domain‐general function in these scheduling operations. However, other 

hypotheses have also been proffered, such as those by Burgess et al. 


Brodmann area 11 is one of Brodmann's 

cytologically defined regions of the brain. It is 

involved in planning, reasoning, and decision 

making. 

Brodmann area 11, or BA11, is part of the frontal cortex in the 

human brain. BA11 covers the medial part of the ventral surface of 

the frontal lobe. 

Prefrontal area 11 of Brodmann‐1909 is a subdivision of the frontal 

lobe in the human defined on the basis of cytoarchitecture. Defined 

and illustrated in Brodmann‐1909, it included the areas 

subsequently illustrated in Brodmann‐10 as prefrontal area 11 and 

rostral area 12. 

prefrontal area 11 is a subdivision of the cytoarchitecturally defined 

frontal region of cerebral cortex of the human. As illustrated in 

Brodmann‐10, It constitutes most of the orbital gyri, gyrus rectus 

and the most rostral portion of the superior frontal gyrus. It is 

bounded medially by the inferior rostral sulcus (H) and laterally 

approximately by the frontomarginal sulcus (H). Cytoarchitecturally 

it is bounded on the rostral and lateral aspects of the hemisphere 

by the frontopolar area 10, the orbital area 47, and the triangular 

area 45; on the medial surface it is bounded dorsally by the rostral 

area 12 and caudally by the subgenual area 25. In an earlier map, 

the area labeled 11, i.e., prefrontal area 11 of Brodmann‐1909, was 

larger; it included the area now designated rostral area 12. 


Brodmann area 46, or BA46 

46, is part of the frontal cortex 

in the human brain. It is between BA10 and BA45. 

BA46 is known as middle frontal area 46. In the human brain it 

occupies approximately the middle third of the middle frontal 

gyrus and the most rostral portion of the inferior frontal gyrus. 

Brodmann area 46 roughly corresponds with the dorsolateral 

prefrontal cortex (DLPFC), although the borders of area 46 are 

based on cytoarchitecture rather than function. The DLPFC also 

encompasses part of granular frontal area 9, directly adjacent on 

the dorsal surface of the cortex. 

Cytoarchitecturally, BA46 is bounded dorsally by the granular frontal area 

9, rostroventrally by the frontopolar area 10 and caudally by the 

triangular area 45 (Brodmann‐1909). There is some discrepancy between 

the extent of BA8 (Brodmann‐1905) and the same area as described by 

Walker (1940) 

The DLPFC plays a role in sustaining attention and working 

memory. Lesions to the DLPFC impair short‐term memory and 

cause difficulty inhibiting responses. Lesions may also eliminate 

much of the ability to make judgements about what's relevant 

and what's not as well as causing problems in organization. 

The DLPFC has recently been found to be involved in exhibiting 

self‐control. The dorsolateral prefrontal cortex, which is one of the few 

areas deactivated during REM sleep. Neuroscientist J. Allan Hobson has 

hypothesized that activation of the dorsolateral prefrontal cortex produce 

lucid dreams. 


The limbic system is also tightly connected to the 

prefrontal cortex. 

Some scientists contend that this connection is 

related to the pleasure obtained from solving problems. To 

cure severe emotional disorders, this connection was 

sometimes surgically severed, a procedure of 

psychosurgery, called a prefrontal lobotomy. Patients who 

underwent this procedure often became passive and 

lacked all motivation. 

There is circumstantial evidence that the limbic 

system also provides a custodial function for the 

maintenance of a healthy conscious state of mind. 

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The Brodmann area 32 

32, also known in the 

human brain as the dorsal anterior cingulate area 

32, refers to a subdivision of the cytoarchitecturally 

defined cingulate region of cerebral cortex. In the 

human it forms an outer arc around the anterior 

cingulate gyrus. The cingulate sulcus defines 

approximately its inner boundary and the superior 

rostral sulcus (H) its ventral boundary; rostrally it 

extends almost to the margin of the frontal lobe. 

Cytoarchitecturally it is bounded internally by the 

ventral anterior cingulate area 24, externally by 

medial margins of the agranular frontal area 6, 

intermediate frontal area 8, granular frontal area 9, 

frontopolar area 10, and prefrontal area 11‐1909. 

(Brodmann19‐09). 

Dorsal region of anterior cingulate gyrus is 

associated with rational thought processes, most 

notably active during the Stroop task. 


Stroop effect is a 

demonstration of the reaction time of a 

task. When the name of a color (e.g., 

"blue," "green," or "red") is printed in a 

color not denoted by the name (e.g., the 

word "red" printed in blue ink instead of 

red ink), naming the color of the word 

takes longer and is more prone to errors 

than when the color of the ink matches the 

name of the color. The effect is named 

after John Ridley Stroop who first 

published the effect in English in 1935. The 

effect had previously been published in 

Germany in 1929. The original paper has 

been one of the most cited papers in the 

history of experimental psychology, leading 

to more than 700 replications. The effect 

has been used to create a psychological 

test (Stroop 

Test) that is widely used in 

clinical practice and investigation. 

This test is considered to measure selective 

attention, cognitive flexibility and processing 

speed, and it is used as a tool in the 

evaluation of executive functions. An 

increased interference effect is found in 

disorders such as brain damage, dementias 

and other neurodegenerative diseases, 

attention‐deficit hyperactivity disorder, or a 

variety of mental disorders such as 

schizophrenia, addictions, and depression 

The anterior cingulate cortex has been related 

to the processing of the Stroop effect 

Figure 1 from Experiment 2 of the original description of the Stroop 

Effect (1935). 1 is the time that it takes to name the color of the dots 

while 2 is the time that it takes to say the color when there is a conflict 

with the written word 

Brodmann area 24 is part of the anterior 

cingulate in the human brain. 

In the human this area is known as ventral anterior 

cingulate area 24, and it refers to a subdivision of the 

cytoarchitecturally defined cingulate cortex region of 

cerebral cortex (area cingularis anterior ventralis). It 

occupies most of the anterior cingulate gyrus in an arc 

around the genu of corpus callosum. Its outer border 

corresponds approximately to the cingulate sulcus. 

Cytoarchitecturally it is bounded internally by the 

pregenual area 33, externally by the dorsal anterior 

cingulate area 32, and caudally by the ventral 

posterior cingulate area 23 and the dorsal posterior 

cingulate area 31. 

Francis Crick, one of the discoverers of DNA, listed 

area 24 as the seat of free will because of its 

centrality in abulia and amotivational syndromes. 


Aboulia or Abulia (from the Greek "αβουλία", meaning 

"non‐will"), in neurology, refers to a lack of will or initiative 

and is one of the Disorders of Diminished Motivation or 

DDM. Aboulia falls in the middle of the spectrum of 

diminished motivation, with apathy being less extreme and 

akinetic mutism being more extreme than aboulia. A 

patient with aboulia is unable to act or make decisions 

independently. d It may range in severity from subtle bl to 

overwhelming. It is also known as Blocq's disease (which 

also refers to abasia and astasia‐abasia). Abulia was 

originally considered to be a disorder of the will. [ 

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Aboulia has been known to clinicians since 1838. However, in the time since its 

inception, the definition of aboulia has been subjected to many different forms, some 

even contradictory with previous ones. Aboulia has been described as a loss of drive, 

expression, loss of behavior and speech output, slowing and prolonged speech latency, 

and reduction of spontaneous thought content and initiative. The clinical features most 

commonly associated with aboulia are: 

1. Difficulty in initiating and sustaining purposeful movements 

2. Lack of spontaneous movement 

3. Reduced spontaneous movement 

4. Increased response‐time to queries 

5. Passivity 

6. Reduced emotional responsiveness and spontaneity 

7. Reduced social interactions 

8. Reduced interest in usual pastimes 

Especially in patients with progressive dementia, it may affect feeding. Patients may 

continue to chew or hold food in their mouths for hours without swallowing it. The 

behavior may be most evident after these patients have eaten part of their meals 

and no longer have strong appetites. 

Amotivational syndrome is a psychological condition associated 

with diminished inspiration to participate in social situations and activities, 

with lapses in apathy caused by an external event, situation, substance (or 

lack of), relationship, or other cause. 

While some have claimed that chronic use of cannabis causes amotivational 

syndrome in some users, empirical studies suggest that there is no such thing 

as "amotivational syndrome", per se, but that chronic cannabis intoxication 

can lead to apathy and amotivation. From a World Health Organization report: 

The evidence for an "amotivational syndrome" among adults consists largely 

of case histories i and observational reports (e.g. Kl Kolanskyand Moore, 1971; 

Millman and Sbriglio, 1986). The small number of controlled field and 

laboratory studies have not found compelling evidence for such a syndrome 

(Dornbush, 1974; Negrete, 1983; Hollister, 1986)... (I)t is doubtful that 

cannabis use produces a well defined amotivational syndrome. It may be more 

parsimonious to regard the symptoms of impaired motivation as symptoms of 

chronic cannabis intoxication rather than inventing a new psychiatric 

syndrome. 

Apathy (also called impassivity or 

perfunctoriness) is a state of 

indifference, or the suppression of emotions 

such as concern, excitement, motivation and 

passion. An apathetic individual has an 

absence of interest in or concern about 

emotional, social, spiritual, philosophical or 

physical life. 

They may lack a sense of purpose or 

meaning in their life. He or she may also 

exhibit hb insensibility bl or sluggishness. The 

opposite of apathy is flow. In positive 

psychology, apathy is described as a result of 

the individual feeling they have much more 

than the level of skill required to confront a 

challenge. It may also be a result of 

perceiving no challenge at all (e.g. the 

challenge is irrelevant to them, or conversely, 

they have learned helplessness). 

Brodmann area 25 (BA25) is an area in the 

cerebral cortex of the brain and delineated based on 

its cytoarchitectonic characteristics, also called the 

subgenual area, area subgenualis or subgenual 

cingulate. It is the 25th "Brodmann area" defined by 

Korbinian Brodmann (thus its name). BA25 is located in the 

cingulate region as a narrow band in the caudal portion of 

the subcallosal area adjacent to the paraterminal gyrus. The 

posterior parolfactory sulcus separates the paraterminal 

gyrus from BA25. Rostrally it is bound by the prefrontal area 

11 of Brodmann. This region is extremely rich in serotonin 

transporters and is considered as a governor for a vast 

network involving areas like hypothalamus and brain stem, 

which influences changes in appetite and sleep; the 

amygdala and insula, which affect the mood and anxiety; the 

hippocampus, which plays an important role in memory 

formation; and some parts of the frontal cortex responsible 

for self‐esteem. 

One study has noted that BA25 is metabolically overactive in treatmentresistant 

depression and has found that chronic deep brain stimulation in the 

white matter adjacent to the area is a successful treatment for some patients. 

A different study found that metabolic hyperactivity in this area is associated 

with poor therapeutic response of persons with Major Depressive Disorder to 

cognitive‐behavioral therapy and venlafaxine 


Brodmann area 33, , also known as 

pregenual area 33, is a subdivision 

of the cytoarchitecturally defined 

cingulate region of cerebral cortex. It 

is a narrow band located in the 

anterior cingulate gyrus adjacent to 

the supracallosal gyrus in the depth 

of the callosal sulcus. 

Cytoarchitecturally it is bounded by 

the ventral anterior cingulate area 

24 and the supracallosal gyrus 

(Brodmann‐1909). 


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Impairment of social and moral behavior 

related to early damage in human prefrontal 

cortex 

Steven W. Anderson, Antoine Bechara, Hanna Damasio, Daniel Tranel & 

Antonio R. Damasio 

Department of Neurology, Division of Behavioral Neurology and Cognitive 

Neuroscience, The University of Iowa College of Medicine, Iowa City, Iowa 52242, 

USA 

The long-term consequences of early prefrontal cortex lesions 

occurring before 16 months were investigated in two adults. As is the 

case when such damage occurs in adulthood, the two early-onset 

patients had severely impaired social behavior despite normal basic 

cognitive abilities, and showed insensitivity to future consequences of 

decisions, defective autonomic responses to punishment contingencies 

and failure to respond to behavioral interventions. Unlike adult-onset 

patients, however, the two patients had defective social and moral 

reasoning, suggesting that the acquisition of complex social 

conventions and moral rules had been impaired. Thus early-onset 

prefrontal damage resulted in a syndrome resembling psychopathy. 

เด็กสมาธิสั้น ซน พฤติกรรมไม่เหมาะสมกับกาลเทศะ 

(Attention Deficit/Hyperactivity: AD/HD) 

ระบบประสาทสมองใน 

เด็กสมาธิสั้น ซน 

พฤติกรรมไม่เหมาะสม 

กับกาลเทศะ 

มีความผิดปกติของ 

สารเคมสอประสาทใน 

ีสื 

่ ส 

สมองโดปามีน 

(Dopamine) 

Prefrontal lobe syndrome 

• Personality changes 

• Deficits in strategic planning 

• Perseveration 

• Release of primitive reflexes 

• Abulia = general slowing of the intellectual 

faculties i.e. apathetic, slow speech etc. 

The Moral Brain and 

decision making 

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19/07/54 

Fig. 2. Brain areas exhibiting differences in activity between conditions shown in 

three axial slices of a standard brain (28). Slice location is indicated by Talairach (28) 

z coordinate. Data are for the main effect of condition in Experiment 1. Colored areas 

reflect the thresholded F scores. Images are reversed left to right to follow radiologic convention. 

Fig. 1. Effect of condition on activity in brain areas identified in Experiment 1. R, 

right; L, left; B, bilateral. Results for the middle frontal gyrus were not replicated in 

Experiment 2. The moral‐personal condition was significantly different from the 

other two conditions in all other areas in both Experiments 1 and 2. In Experiment 

1 the medial frontal and posterior cingulate gyri showed significant differences 

between the moral‐impersonal and non‐moral conditions. In Experiment 2 only the posterior cingulate gyrus was 

significantly different in this comparison. Brodmann's Areas and Talairach (28) coordinates (x, y, z) for each area are as 

follows (left to right in graph): 9/10 (1, 52, 17); 31 (-4, -54, 35); 46 (45, 36, 24); 7/40 (-48, -65, 26); 7/40 (50, -57, 20). 

Jorge Moll, Roland Zahn, Frank Krueger and Jordan Grafman are at The Cognitive 

Neuroscience Section, National Institute 

of Neurological Disorders and Stroke, Building 10; Room 5C205; MSC 1440, NIH, 

Bethesda, Maryland 20892‐1440, USA. 

Ricardo de Oliveira‐Souza is at the Cognitive and Behavioral Neuroscience Unit, 

LABS‐D’Or Hospital Network, R. Pinheiro Guimaraes 22, 3rd floor, Rio de Janeiro 

22281‐080, Brazil. 

Correspondence to J.G. e‐mail: grafmanj@ninds.nih.gov 

Cognitive Neuroscience Section, NINDS, NIH: 

http://intra.ninds.nih.gov/Lab.asp?Org_ID=83 

Cognitive and Behavioural Neuroscience Unit, 

LABS‐D’Or Hospital Network: 

http://www.rededor.com.br/cbnu/ 

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19/07/54 

Frontal lobe and Executive Function 

Disorder 

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19/07/54 

The Frontal Lobes Are Considered 

Our Emotional Control Center and 

Home to Our Personality 

There Is No Other Part of the Brain Where 

Lesions Can Cause Such a Wide Variety of 

Symptoms. 

‐ involved in motor function, problem 

solving, spontaneity, memory, language, 

initiation, judgement, impulse control, 

and social iland sexual behavior. bh ‐ extremely vulnerable to injury due to 

their location at the front of the cranium, 

proximity to the sphenoid wing and their 

large size. 

There Are Important Asymmetrical Differences 

in the Frontal Lobes. 

The left frontal lobe is involved in controlling 

language related movement, whereas the 

right frontal lobe plays a role in non‐verbal 

abilities. 

Some researchers emphasize that this rule is 

not absolute and that with many people, 

both lobes are involved in nearly all 

behavior. 

Disturbance of motor function is typically 

characterized by loss of fine movements 

and strength of the arms, hands and fingers. 

Complex chains of motor movement also seem 

to be controlled by the frontal lobes. 

Patients with frontal lobe damage exhibit little 

spontaneous facial expression, which points 

to the role of the frontal lobes in facial 

expression. 

Broca's Aphasia, or difficulty in speaking, has 

been associated with frontal damage. 

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19/07/54 

An interesting phenomenon of frontal lobe 

damage is the insignificant effect it can have 

on traditional IQ testing. 

Frontal lobe damage seems to have an 

impact on divergent thinking, or flexibility 

and problem solving ability. 

There is also evidence showing lingering 

interference with attention and memory 

even after good recovery from a TBI. 

One Characteristics of Frontal Lobe Damage 

Is Difficulty in Interpreting Feedback From the 

Environment 

Perseverating on a response, risk taking and 

non‐compliance with rules, and impaired 

associated learning (using external cues 

to help guide behavior) are a few 

examples of this type of deficit. 

The frontal lobes are also thought to play a 

part in our spatial orientation, including 

our bodies orientation in space. 

One of the Most Common Effects of Frontal 

Damage Can Be a Dramatic Change in Social 

Behavior. 

A person's personality can undergo 

significant changes after an injury to the 

frontal lobes, especially when both lobes 

are involved. 

There are some differences in the left versus 

right frontal lobes in this area. 

Left frontal damage usually manifests as 

pseudodepression and right frontal 

damage as pseudopsychopathic. 

One of the most common effects of frontal 

damage can be a dramatic change in social 

behavior. 

Sexual behavior can also be effected by 

frontal lesions. 

Orbital frontal damage can introduce 

abnormal sexual behavior, while 

dorsolateral lesions may reduce sexual 

interest. 

Some Common Tests for Frontal Lobe 

Function Are: 

Wisconsin Card Sorting (response 

inhibition); 

Finger Tapping (motor skills); 

Token Test (language skills). 

The Wisconsin Card Sorting Test 

(WCST) is a neuropsychological test of "setshifting", 

i.e. the ability to display flexibility in the 

face of changing schedules of reinforcement. 

The WCST was written by David A. Grant and Esta A. Berg. 

The Professional Manual for the WCST was written by Robert 

K. Heaton, Gordon J. Chelune, Jack L. Talley, Gary G. Kay, and 

Glenn Curtiss. 

Clinically, the test is widely used by neuropsychologists, 

clinical psychologists, neurologists and psychiatrists in 

patients with acquired brain injury, neurodegenerative 

disease, or mental tlillness such as schizophrenia. h i It has been In particular, patients with ihlesions 

considered a measure of executive function because of its of the dorsolateral frontal lobe 

reported sensitivity to frontal lobe dysfunction. As such, the 

make a higher number of 

WCST allows the clinician to assess the following "frontal" 

lobe functions: strategic planning, organized searching, 

perseverative errors than control 

utilizing environmental feedback to shift cognitive sets, participants. 

directing behavior toward achieving a goal, and modulating A recent factor analysis of the WCST 

impulsive responding. The test can be administered to those has shown these perseverative errors 

6.5 years to 89 years of age. 

to be the most useful outcome 

Although successful completion of the test relies upon a measure in assessing cases. A more 

number of intact cognitive functions including attention, sophisticated description of deficits of 

working memory, and visual processing, it is loosely termed a this type is "executive dysfunction". 

"frontal lobe" test on the basis that patients with any sort of 

frontal lobe lesion generally do poorly at the test. 

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19/07/54 

Current News: 

‐ Multi-Tasking Pinpointed to Frontal Lobes. 

‐ Two Brain Areas Involved in Doing Math. 

‐ Brain Can Compensate for Damage to Language 

Systems After Injury. 

‐ Injury to Frontal Lobes May Affect Appreciation 

of Humor. 

Finger Tapping (motor skills) 

Executive Function Disorder 

The frontal lobes represent a large area 

of the brain and brain centers within 

the frontal lobe have numerous 

interconnections with other parts of 

the brain. 

These include connections with emotion 

and mood centers as well as cognitive 

centers. 


This high degree of complexity results in 

a number of syndromes that are 

associated with lesions of this area. 

There are three general anatomical 

divisions of the frontal cortex: the 

limbic, the precentral and the 

prefrontal cortices. 

The Frontal Lobes 

The precentral cortex consists of areas 

that lie immediately before the 

central sulcus. 

These consist of the primary and 

secondary motor control areas. 


The limbic component consists of 

the inferior and medial parts of the 

cingulate gyrus and the posterior 

parts of the orbital frontal areas. 

These areas have inter‐ connections 

with the amygdala, hippocampus, 

thalamus and other parts of the 

limbic system. 

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19/07/54 


The prefrontal cortex is anterior to the 

motor control areas and comprises the 

greater part of the frontal lobe. 

It is subdivided into the dorsolateral, 

mesial and orbital areas. 

These sections are histologically distinct 

and probably represent functional 

differences. 


The prefrontal cortex is the area 

implicated in the studies of 

personality and the behavioral 

effects of frontal lobe lesions. 

It has extensive interconnections 

with virtually every other part of 

the cerebrum. 


These include association areas in 

the temporal, occipital and parietal 

lobes, the limbic system, the dorsal 

medial nucleus of the thalamus 

and the basal ganglia. 


Bilateral lesion of the inferior medial 

sections of the frontal lobes causes 

emotional and behavioral changes. 

Intellectual impairment results from 

lesion of the dorso‐ lateral portion of 

the frontal lobes. 

Cognitive Impairment 

Although patients with frontal lobe 

lesions may have extensive brain 

injury and numerous behavioral 

changes they will typically score 

within the normal range on IQ tests. 

Cognitive Impairment 

The cognitive impairment associated with 

frontal lobe lesions involve cognitive 

abilities that are not measured by 

conventional IQ tests. 

These include impairment of hypothesis 

testing and abstract reasoning, memory 

disorder, attention deficits and difficulty 

in initiation of cognitive activity. 

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19/07/54 

Impairment of Abstract Reasoning, 

Hypothesis Testing and Modulation of 

Cognition 

The overriding function of the frontal areas 

is to modulate and control motor function, 

emotion, attention and other cognitive 

activity. 

Virtually all aspects of frontal lobe impairment 

can be considered a specific aspect 

of a general deficit of control. 

Impairment of Abstract Reasoning, Hypothesis 

Testing and Modulation of Cognition 

In the domain of reasoning, a deficit of 

modulation is manifested as poor abstract 

reasoning and failure to maintain goal‐ 

directed behavior. 

Abstract reasoning involves making complex 

associations between semantic elements 

and identifying super‐ordinate categories, 

reasoning by general rules and formulating 

hypotheses. 



Cognition 

If abstract reasoning is not present then the 

patient has difficulty formulating the 

super‐ordinate category that subsumes 

individual semantic elements. 

For example, the patient may not be able to reason that 

cars, trains, airplanes and the like, are members of the 

category of modes of transportation. 



Cognition 

Another manifestation of abstract reasoning 

involves the development of rules that 

guide future behavior. 

The reasoning person identifies common 

features and themes in the experiences of 

everyday life and formulates general rules 

that govern behavior in these situations. 



Cognition 

Rules may also be taught by others but reasoning 

people usually verify and endorse 

the validity of rules before using them. 

People who have sustained injury to the 

frontal lobes have difficulty formulating 

these rules. 


Hypothesis Testing and Modulation 

of Cognition 

Indeed, even if a rule is given to the patient 

there is still great difficulty in using it to 

guide bh behavior. 

As a result of this general inability to 

formulate and use rules, the patient 

cannot conceptualize goal states and use 

the goals as objectives to guide thought 

and actions. 

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19/07/54 



Cognition 

Actions are motivated by very concrete, 

superficial goals, such as immediate 

gratification of simple impulses. 

Hypothesis formulation and testing also involves 

the generalization of experiences in the form of 

rules or general principles. This cognitive 

function is likewise affected by lesions of the 

frontal lobes. 

Disturbance of Behavior and 

Personality 

Patients with lesions of the ventro‐ 

medial portion of the frontal lobes 

have a behavioral syndrome 

characterized by lack of originality and 

creativity, impairment of attention, and a 

tendency to display inappropriate 

emotions and behavior. 


Personality 

They have difficulty initiating behavior; 

when they do engage in activity, they 

may continue the activity it without 

t 

stopping. 

They may only start activity when 

prompted by others. 


Personality 

Although controversial, emotional 

disturbance most often results from 

lesion of the orbital frontal areas. 

These areas have interconnections 

with the amygdala and 

hypothalamus. 


Personality 

Emotional disturbances include laughing 

or crying in situations inappropriate to 

the emotion. 

The emotional response also appears 

superficial and variable. 

The patient usually has no awareness 

that their emotional response is 

incorrect or extreme. 

Aphasia 

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19/07/54 

Language Impairment 

Broca's area resides in the left frontal 

lobe and lesion of this area produces a 

well‐known impairment of language 

referred to as Broca's aphasia. 

Patients with dorsolateral frontal lobe 

lesions may also have additional 

language impairment that is distinct 

from Broca's aphasia. 


The first of these is a general reduction of 

language production although language 

utterances that are produced are fluent 

and maintain correct syntax. 

Patients with frontal lobe lesions have 

difficulty initiating speech and 

maintaining a complex, spontaneous 

conversation. 


This is referred to as a deficit in 

"verbal fluency", although language 

productions are actually fluent. 


Patients with frontal lesions in secondary 

motor control areas may also display 

mutism. 

In particular, lesions of the cingulum often 

result in essential mutism. 

Here, the patient comprehends language but 

cannot produce any vocalizations, including 

language. 


This is viewed as a deficit of the basic 

motor control of the oral apparatus to 

the point where there is no initiation of 

activity. 

The patient is often indifferent to 

communication in general and does 

not show the frustration characteristic 

of Broca's aphasia. 


A pure agraphia is also associated with 

lesions of supplemental motor areas of the 

left dorsolateral frontal lobe (Exner's 

area). 

Exner's area (Broadman area #46 

46) is above 

Broca's area (Broadman area #44,45) and 

anterior to the primary motor control area. 

In this disorder, the patient is not aphasic 

but has difficulty writing and reading. 

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19/07/54 

Impairment of Motor Function 

The highly controlled, volitional components 

of motor control are located in the frontal 

lobes on the dorso‐ lateral surface anterior 

to and including the primary motor control 

area (the motor strip). 

Other components of the motor control 

system are the Basal Ganglia and the 

Cerebellum. 

The cortical system in the frontal lobes are 

involved in the complex control of skeletal 

muscles in the execution of actions. 


Lesions of the dorsolateral frontal areas 

results in a number of motor 

impairments. 

These include: 

‐perseveration, 

‐inco‐ordination, 

‐motor impersistence, and 

‐hypokinesia. 


‐Patients with left frontal lobe lesions 

may also have ideomotor apraxia. 

-Lesions within hemisphere cause 

worse motor impairment of the 

opposite extremities. 


These deficits again involve the 

general modulation and control 

functions that are characteristic 

of the frontal lobes. 


There is some evidence that control is 

lateralized to each frontal area. 

The left hemisphere is dominant for 

motor control and the modulation of 

language. 

The right hemisphere is more involved 

in the modulation of actions that are 

executed in a spatial context, such as 

three‐dimensional block construction. 

Impairment of Reflexes 

The frontal lobes play the primary role in the 

inhibition of fundamental reflexes that 

were presumably inherited as part of 

primitive brain structures characteristic of 

the primate brain. 

These reflexes include the grasp reflex and 

the snout and sucking reflexes. The grasp 

reflex is elicited by stroking the skin of the 

palm. 

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19/07/54 


The patient grasps the object and has 

difficulty releasing the grasp even when 

told to attend to the hand and release 

the grasp. 

Snout and sucking reflexes are elicited i by 

stimulating the lips and space between 

the upper lip and the nose. Here, the 

patient extends the lips outward for the 

snout reflex. 


The patient is compelled to suck on 

an object placed in the lips when 

the suck reflex is present. 

The frontal lobes usually inhibit these 

reflexes during childhood and 

adulthood. When the frontal lobe is 

lesioned, this inhibition is removed 

and the reflexes return. 

Impairment of Social Behavior 

Since frontal lobe lesions result in a 

pervasive defect in planning and 

modulation of behavior, these patients 

have compelling deficits in maintining 

appropriate p social responses. 

Social perception and action are very 

complex. In addition, people do not 

have a wide tolerance for social 

behavior; even minor deviations in 

social behavior are noticeable. 

Impairment of Social Behavior 

Patients with frontal lobe lesions have great 

difficulty generating appropriate 

behavioral options in social situations and 

then choosing the best alternative. 

They also base their behavior on concrete 

simple motivations and cannot formulate 

or comprehend more complex or abstract 

reasons for acting. 

Much social behavior requires a complex 

and abstract appreciation of the social 

setting. 

Confabulation and Reduplication 

Syndrome 

Patients with severe frontal lobe lesions 

tend to fabricate quick, impulsive 

answers to questions. 

Some responses may be quite fanciful 

and imaginative. The patient cannot 

inhibit a response in order to check its 

validity. 


Syndrome 

This tendency to fabricate an answer 

is called confabulation. 

It is most common among patients 

with basal forebrain lesions and 

among patients with additional 

impairment of memory ability. 

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19/07/54 


Syndrome 

Another syndrome that is similar to 

confabulation is reduplication. 

Here, the patient with a frontal lobe 

lesion confabulates that the current 

environment, usually the hospital, is 

actually another place that is similar 

to the current setting but has a 

different name and location. 


Syndrome 

The patient may even claim that the current 

hospital is a university dormitory or an 

apartment building. 

The confabulated place is always somewhere 

else and it is usually familiar to the patient, 

such as the hospital in the patient's home 

town. 

The patient will often maintain this 

confabulation even when confronted with 

salient, contradictory information. 

Apraxia 

Callosal Disconnection 

Syndromes 


43

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Blood supply 

Branches of the middle cerebral artery provide most of 

the arterial blood supply for the primary motor cortex. 

The medial aspect (leg areas) is supplied by branches of 

the anterior cerebral artery. 

Neural input from the thalamus 

The primary motor cortex receive thalamic input from 

the Ventral lateral nucleus of the Thalamus. 

Pathology 

Lesions of the precentral gyrus result in paralysis of the 

contralateral side of the body (facial palsy, arm‐/leg 

monoparesis, hemiparesis) ‐ see upper motor neuron. 

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Schizophrenia 

• Schizophrenia is a psychotic disorder involving 

disturbance of thought, emotion and behavior 

• The lifetime prevalence of schizophrenia is 

about 1% 

– Onset is usually in late adolescence 

– Substance abuse is a co‐morbid condition in 50% of 

schizophrenia patients 

Ch 11.1 

Positive Symptoms of Schizophrenia 

Negative Symptoms of Schizophrenia 

• Positive symptoms involve excesses or distortions 

– Disorganized speech (thought disorder) 

– Hallucinations are sensory experiences that occur in the 

absence of environmental stimulation 

• Hallucinations are commonly auditory 

– Delusions are beliefs that are contrary to reality 

• Persecutory delusions are common 

• Negative schizophrenia symptoms are characterized by 

behavioral deficits 

– Avolition refers to a lack of energy and an inability to persist 

in routine activities 

– Alogia refers to a reduction in the amount or content of 

speech 

– Anhedonia is an inability to experience pleasure 

– Asociality refers to a severe impairment in social 

relationships 

Ch 11.2 

Ch 11.3 

Etiology of Schizophrenia 

• Genetic studies using twin, family and adoption 

techniques reveal that a predisposition for 

schizophrenia is transmitted genetically 

Genetic Studies of Schizophrenia 

Relation to 

Proband 

Spouse 1.00 

Grandchildren 2.84 

Nieces/nephews 2.65 

Children 9.35 

Siblings 7.30 

DZ twins 12.08 

MZ twins 44.30 

Percentage 

Schizophrenic 

Ch 11.5 

Ch 11.6 

45

19/07/54 

Biochemistry of Schizophrenia 

• Dopamine theory holds that the positive symptoms of 

schizophrenia result from excessive activity of 

dopamine in brain 

– Anti‐schizophrenia drugs block dopamine receptors 

• The anti‐schizophrenia h i drugs take several weeks to act clinically, i ll yet 

rapidly block dopamine receptors 

– Ingestion of amphetamine can induce psychosis; 

amphetamine causes the release of dopamine from neurons 

Ch 11.7 

Dopamine Theory of Schizophrenia 

Brain Pathology in Schizophrenia 

• Brains of schizophrenic patients show 

– Reduced volume of temporal and frontal cortex 

– Enlarged ventricles (reflecting loss of brain cells) 

• For 12 of 15 twins, the schizophrenic h i twin could be 

identified by enlarged ventricles 

– Reduced metabolic activity within prefrontal cortex 

(frontal hypoactivation) 

Ch 11.8 

Ch 11.9 

46

19/07/54 

DSM‐IV Schizophrenia Categories 

• Disorganized schizophrenia involves 

– Disorganized speech and flat affect 

– A general disruption of behavior 

• Catatonic schizophrenia involves 

– Prolonged motor immobility states that alternate with 

periods of excitability 

• Paranoid schizophrenia involves the presence of 

prominent delusions including persecution and 

grandiosity 

Ch 11.4 

Early Forms of Treatment 

Insulin Coma Therapy 

Psychosurgery 

Electroconvulsive Therapy (ECT) 

Smooth Pursuit Eye Tracking 

Biological Interventions 

Neuroleptics 

Haldol & Clozapine 

Trial and Error 

“Extrapyramidal” Side Effects 

Tardive Dyskineasia 

Akineasia 

Therapies for Schizophrenia 

• Psychosurgery is the intentional destruction of 

brain tissue to alter behavior 

– Prefrontal lobotomy was used to treat 

schizophrenia 

• Drug therapies supplanted psychosurgery 

– Use of neuroleptic medications to treat positive 

symptoms of schizophrenia 

• Chlorpromazine was introduced in the US in 1954 

Ch 11.10 

Psychological Treatments for 

Schizophrenia 

• Social‐skills training involves teaching behaviors to 

interact successfully with others 

• Family therapy aims to reduced expressed emotion 

(hostility, overly critical) 

• Personal therapy aims to reduce expressed emotion, 

uses relaxation techniques and teaches social skills 

Ch 11.11` 

47

The Frontal lobes - Mahidol University

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