Figure 2: Vertical grouping of orientation is independent of visual cortex.

(a) Two recording probes are placed in matching retinotopic positions in V1 and the sSC, whereas a LED-coupled fibre was placed above V1. The middle panel shows the ON-response fields for one V1 site (red) and sSC site (blue) during a simultaneous recording. The right panel is an example of expression by viral transfection imaged by fluorescent microscope. The red lines indicate the estimated outline of V1 based on stereotactic coordinates. (b) Responses of multi-units in sSC and layer 5 of binocular V1 in the injected area of an example experiment (left and middle-down left) and visual evoked potential in layer 5 of V1 (middle-down right) during light-off condition (black) and light-on conditions (blue) show that V1 L5 is silenced, while sSC remains active. Error bars in tuning curves are mean±s.e.m. Time 0 s is the onset of the visual stimulus. The light was turned on 1 s before this. The middle-top panel is the corresponding raster plot of spikes in V1 L5 when the light is off (left) and on (right). The right panel shows the effect of shining light on silencing all layers of V1 of 6 mice (n=29). (c) Example tuning curves from four depths in the sSC, separated by 50 μm, with V1 active (black) and silenced (blue). (d) Orientation tuning of units with V1 active (left) and silenced (right) is not changed (P=0.99, Wilcoxon signed rank sum test, n=33, 6 mice). (e) Circular variances of eight vertical penetrations in the sSC in light off (V1 active) and light on (V1 silenced) conditions is not significantly changed (P=0.31, Wilcoxon signed rank sum test, 6 mice).