Figure 3.

CLA neurons projecting to RSC (retRSC) reside within the ventral CLA core and co-project mainly to higher cortical targets. (A) Double-virus injection strategy used to label CLA neurons projecting to the RSC and its axon arborizations. (B) CLA-specific expression of Cre and mCherry. vCLA core boundaries (white dotted ellipse) are demarcated based on parvalbumin (PV) antibody staining. (C) Mapping of retRSC neuron axons; images show mCherry expression (red) within DAPI-stained (blue) coronal sections. Yellow arrows denote viral injection sites. CLA neurons projecting to RSC also project to several other higher-order cortical structures. Labels indicate regions receiving CLA axons. PL, Prelimbic cortex; ORBm, ORBv, Orbital frontal cortex medial, ventral; ACCd, ACCv, Anterior cingulate cortex dorsal, ventral; IL, Infralimbic cortex; M1, M2, Primary and secondary motor cortex; RSCd, vRSCv, Retrosplenial cortex dorsal, ventral; PPC, Posterior Parietal Cortex; V1, V2, V2 m, V2l, primary and secondary visual cortex, medial, lateral; Ect, Ectorhinal cortex; Prh, Perirhinal cortex; TeA, Temporal association cortex; PreS, Presubiculum; PoS, Postsubiculum; ENTl, ENTm, Entorhinal cortex lateral, medial. (D) Mean fraction of axonal density for all innervated regions, sorted by density. Red arrow and text indicate retrograde Cre origin (RSC). Orbital, anterior cingulate and agranular insula had heavier innervation compared to RSC. Colors represent region categories: Association—green, Sensorimotor—pink, and Subcortical—Blue. Note different ranges for contralateral and ipsilateral values.