FIGURE 8.

Relation of iCC projections from M2 L2/3 to PRC with those to OFC or to M1. (A) Upper L2/3 distributions of M2 iCC cells projecting to OFC and to PRC, and their partial double-labeling. Left, M2 somata retrogradely labeled from OFC (arrows and arrowhead; labeled by CTB555). Right, M2 somata retrogradely labeled from PRC (labeled by Fast Blue). Arrowhead, double-labeled cell; arrows, OFC-projecting cells not labeled by PRC injection (asterisks). Oblique section, 20 μm thickness. (B) Segregation of iCC projections from M2 L2/3 to M1 and to PRC. Left, M2 somata projecting to M1 in lower L2/3 (arrows; labeled by CTB555), not labeled from PRC (asterisks in right). Right, M2 somata projecting to PRC in upper L2/3 (labeled by Fast Blue). (C) Schematic summary of M2 L2/3 iCC projections. OFC-projecting cells are more prevalent in L2/3a, some of which also send axon collaterals to PRC. By contrast, M1-projecting cells are abundant in L2/3b.