Fig. 7
From: Gut vagal sensory signaling regulates hippocampus function through multi-order pathways
Multisynaptic viral tracing approach reveals MS neurons that receive monosynaptic input from the mNTS directly project to the dHPC (dCA3 and DG). a Unilateral iontophoretic co-injection of AAV2/1-hSyn-Cre and CTB (CTB-ir in green; to confirm injection site placement) in the mNTS (n = 3 double hits, n = 13 controls), which drives Cre expression in second-order (but not third-order) neurons based on synaptic virion release from first-order axon terminals18. Scale bar: 100 μm. b, c A 200 nl pressure injection site of a Cre-dependent anterograde tracer (AAV1-CAG-FLEX-TdTomato) in the MS Scale bar: b 200 μm, c 50 μm. Axon terminal fields in the d, e dCA3 and h, i DG of MS neurons that receive direct input from mNTS. Scale bar: d, h 250 μm, e, i 50 μm. A schematic representation of dCA3 (f, g) and DG (j, k) axon terminal field distribution (Made by co-author and adapted from Swanson atlas level 28–3068). (aco anterior commissure, AP area postrema, CA3sr CA3 stratum radiatum, CA3sp CA3 pyramidal layer, DGmo dentate gyrus molecular layer, DGpo DG polymorph layer, DGsg DG granule cell layer, mNTS medial nucleus tractus solitarius, MS, medial septum)
