Figure 5: Timing and laminar profile of perisaccadic firing rate modulation suggests upstream origin.
From: Saccadic modulation of stimulus processing in primary visual cortex
(a) Schematic showing three different sources of saccade-related modulatory signals: (red) signals targeting ‘upstream’ LGN inputs to V1; (green) direct modulatory inputs to V1; (blue) signals targeting downstream cortical structures that provide feedback projections to V1. (b) Perisaccadic firing rate suppression occurred significantly later for neurons with more delayed stimulus responses (Spearman’s rank correlation ρ=0.61; P=6.4 × 10−9; n=76). Red line shows linear fit and black line shows the diagonal. (c) Stimulus-onset-triggered current source density (CSD) profile from an example laminar probe recording. The location of a short-latency current sink is used to estimate the upper and lower boundaries of layer IV. (d) The time of maximal saccadic firing rate suppression was significantly delayed for multi-unit activity from supragranular electrodes (blue; n=58 across 9 recordings) compared with granular (red; n=55) and infragranular (black; n=85) electrodes. (e) Supragranular units also showed temporally delayed stimulus response profiles (see Methods).
