Fig. 2: V2 rather than V1 has monosynaptic connectivity to MEC L5a.

a Schematic illustrating anterograde trans-multisynaptic HSV tracing strategy. b Confocal images showing HSV1 H129 expression at 48 HPI (left) or 60 HPI (right) within the V1, dLGN (inset) and MEC. c Comparison of HSV1 H129 expression within MEC L5a at 48 HPI and 60 HPI (n = 6 mice/group). ** P = 0.0022, two-sided Mann-Whitney U test. d Schematic illustrating anterograde trans-monosynaptic HSV tracing and light stimulation strategy. e Confocal images showing H129-ΔTK-EGFP (green) and c-Fos (red) expression within the MEC when the AAV2/9-EF1α-TK-tdTomato and H129-ΔTK-EGFP were injected into V2M (left) or V2L (right). f Proportion of co-labeled cells in H129-infected MEC L5a cells (V2M, n = 3 mice; V2L, n = 3 mice). g Distribution of c-Fos⁺ cells and HSV-expressing cells in vCE L5a along the ML direction (n = 3 mice). h Schematic illustrating injection of two kinds of HSV1 H129 within unilateral V2L and bilateral V2M, respectively. i Confocal images showing the expression of the two kinds of HSV1 H129 at 48 HPI within the MEC L5a. j The Venn diagram shows the number of the MEC L5a cells receiving V2M projections or V2L projections (n = 8 slices from 4 mice). k Schematic illustrating injection of AAV within V2M and V2L. l Confocal images showing axonal fibers of V2M and V2L in the MEC. m Distribution of axonal fibers of V2M and V2L within the MEC (n = 3 mice). n Schematic illustrating injection of HSV1 H129 within V2M or V2L, followed by whole-cell recordings from EGFP-positive neurons of vCE L5a at 48 HPI. o Two morphological subtypes of MEC L5a neurons (black lines represent axons). p Proportions of HBD and FBD cells in MEC L5a neurons receiving V2M (n = 53 cells from 6 mice) or V2L (n = 46 cells from 5 mice) projections. Scale bars, 100 μm (i), 200 μm (others). Error bars represent SEM (c and g). Shaded error bands represent SEM (m). Source data are provided as a Source Data file.