Fig. 5

Five loops associating the five cerebral structures. This scheme of the brain underlines some important anatomical and functional characteristics to better understand how information flows are processed in the brain. It is proposed that five kinds of neuronal structures bring more and more complexity and flexibility along phylogeny: (i) subcortical structures (the Amygdala (and its inner nuclei, the basolateral complex BLA and the central nucleus CeA), the Hypothalamus, the Superior Colliculus (with its superficial and deep layers) and the Cerebellum), (ii) the Basal Ganglia (with the striatum composed of its dorsolateral part DLS, dorsomedial part DMS and ventral part, also called Nucleus Accumbens NAcc with a shell and a core division; with output structures, the internal Globus Pallidus and the substantia nigra pars reticulata GPI-SNr and internal nuclei, STN (subthalamic nuclei) and GPe (external Globus Pallidus); with dopaminergic regions, ventral tegmental area VTA and substantia nigra pars compacta SNc); (iii) the hippocampus with its main internal structures dentate gyrus DG, CA3 and CA1 and its associated cortical structures (the entorhinal, postrhinal and perirhinal cortex); (iv) five regions of the sensory cortex receiving inputs from the sensory thalamus (the ventral, dorsal, associative and insular cortex); (v) five regions of the frontal cortex including the orbitofrontal cortex OFC, the ventral and dorsal parts of the medial prefrontal cortex vmPFC and dmPFC, the lateral prefrontal cortex with ventral and dorsal parts vlPFC and dlPFC, the frontal eye field FEF and the motor and premotor regions. As explained in more details in the text, colors refer to the major implication of certain regions in these structures, to answer fundamental questions for the selection of goals (what goal and why, respectively, in red and pink) and for their spatial access (where and how, respectively, in light and dark blue), whereas the green color is for associative processes. These colors also refer to preferential projections between these regions, particularly forming five CBG loops between the structures, even if the text also explains that some complex functions result from interactions between different loops. The circuitry within each loop is similar and depicted in Fig. 4