The Frontal lobes - Mahidol University

19/07/54
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.
Brain: Brodmann area 10
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.
Brain: Brodmann area 11
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.
Brain: Brodmann area 46
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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