Fig. 2.

Schematic of the regional and functional neuroanatomy of Darwin X. Gray ellipses denote different neural areas. Arrows denote projections from one area to another. (A) Diagram of cortical-hippocampal connectivity. Input to the neural simulation comes from a charge-coupled device camera, wheel odometry, and IR sensors for wall and platform detection. The simulation contains neural areas analogous to visual cortex (V1, V2/4), the inferotemporal cortex (IT), parietal cortex (Pr), head direction units (HD), anterior thalamic nuclei (ATN), motor areas for egocentric heading (M_HDG), a value system (S), and positive and negative reward areas (R+, R-). The hippocampus is connected with the three major sensor input streams (IT, Pr, ATN), the motor system (M_HDG), and the value system (S). The hippocampus receives rhythmic inhibition from a simulated basal forebrain region (BF). (B) Diagram of connectivity within the hippocampal region. The modeled hippocampus contains areas analogous to entorhinal cortex (EC_IN,EC_OUT), dentate gyrus (DG), and the CA3 and CA1 subfields. These areas contain interneurons that implement feedback inhibition (e.g., CA3 → CA3_FB → CA3) and feed-forward inhibition (e.g., DG → CA3_FF → CA3). See supporting information for details.