Who Needs Emotions? The Brain Meets the Robot

organization of motivational–emotional systems 49
The time scale of these processes can vary from milliseconds to months
and even years, in the case of long-term plasticity.
Modern genetic sequencing techniques combined with advances in
bioinformatics have allowed novel insights into assessments of gene nucleotide
sequence homology throughout evolution and the animal kingdom.
Comparison of sequence relationships in genes between different species
yields evidence of both diversity and conservation of neurochemical signaling
and function. For example, acetylcholine and its corresponding nicotinic
and muscarinic receptors occur across species from the platyhelminths (flatworms)
and nematodes to vertebrates, functioning as a chemical signal in
Figure 3.5 (facing page). Flat map of general forebrain organization, according
to Swanson (2000), showing major pathways subserving emotion and
motivation, as discussed in the text. At the bottom of each figure, the
“behavior control columns” are depicted; the rostral segment governs ingestive,
reproductive, and defensive behaviors, while the more caudal segment
directs exploratory and foraging behaviors. (A) Nearly the entire cerebral
hemispheres project to the behavior control column. Cerebral inputs to the
rostral segment are shown in light gray and those to the caudal segment, in
darker gray. (B) The entire basal ganglia (striatopallidum) gives rise to a
branched projection to the dorsal thalamus and behavior control column,
which in turn generates a branched projection to both the dorsal thalamic
and brain-stem motor regions. The part of the dorsal thalamus innervated by
the basal ganglia and behavior control columns is shown in lighter gray. Keep
in mind that this part of the thalamus projects massively back to the entire
cerebral cortex. (C) The thalamocortical projection, indicated in darker
gray, is influenced by the rostral behavior control column (arising mainly from
the medial dorsal nucleus). AAA, anterior amygdalar area; ACB, nucleus
accumbens; AMv, anteromedial nucleus, ventral part; ATN, anterior thalamic
nuclei; BST, bed nuclei stria terminalis; CEA, central nucleus amygdala; CM,
central medial nucleus; CP, caudoputamen; FRP, frontal pole; FS, striatal
fundus; GP, globus pallidus; LGd, dorsal lateral geniculate nucleus; LP, lateral
posterior nucleus; LSC, lateral septal complex; MA, magnocellular (preoptic)
nucleus; MDm, mediodorsal nucleus, medial part; MEA, medial nucleus
amygdala; MG, medial geniculate nucleus; MSC, medial septal complex;
OCP, occipital pole; OT, olfactory tubercle; PCN, paracentral nucleus; PF,
parafascicular nucleus; PO, posterior complex thalamus; PT, paratenial
nucleus, PVT, paraventricular nucleus thalamus; RE, nucleus reuniens;
SMT, submedial nucleus thalamus; SI, substantia innominata; TEP, temporal
pole; VAL, ventral anterior–lateral complex; VM, ventral medial nucleus;
VPL, ventral posterolateral nucleus; VPM, ventral posteromedial nucleus.
(Adapted from Swanson, 2000, with permission.)