corecircuit_big.png (249.76 kB)
Broad functional architecture of the brain (Cartoon)
A cartoon representation of the core neuropsychiatric circuit. Yellow area is a limited representation of the perceptual system (here we use the visual pathway as the example, from V1 to the inferior temporal cortex). The pink/magenta area represents the policy and action generation system (from frontal limbic cortices progressing to primary motor cortex). The purple central structure represents the striatopallidal nuclei (mainly the striatum). Red structures are the amygdalae. Hippocampus is depicted in blue. Bright green structure is the thalamus. The midbrain with associated dopaminergic projections (green is VTA; black are SNc) is depicted below the brain with an axial cross section.
Note that the sensory pathway sends extensive projections at high levels to the amygdalohippocampal complex, which feeds information in large part to limbic cortices and the basal ganglia. VTA dopaminergic neurons code for the reward prediction error signal which is projected to ventral striatum and limbic cortices. SNc dopaminergic neurons project prediction error signals primarily to dorsal striatal neurons. Nearly all areas of the cortex will have associated corticostriatal loops, but here we depict frontal corticostriatal loops: pink projections are corticostriatal projections, whereas the green projections are thalamocortical projections.
Ultimately, this circuit is performs feature detection/state determination, action generation, and the intermediate step of policy implementation/action selection.
