Figure 1: Vertical grouping of orientation preference in the superficial layer of the mouse superior colliculus.

(a) Examples of orientation and direction tuning. (b) Orientation tuning across different channels on a laminar electrode with 50 μm spacing. Right panels show raster plot of spikes around the onset of all trials to the preferred and orthogonal orientations. (c) Example penetrations with tungsten microelectrodes, depths are 50 μm apart. (d) Orientation selectivity index of 19 high waveform-amplitude single units from horizontal and vertical penetrations (9 mice). Bar indicates mean. (e) Difference of the preferred orientation of the 10 single units (5 mice) encountered on vertical penetrations to the mean preferred angle of all units on the penetration. (f) Histogram of the circular mean of the orientation preference for all 57 penetrations (14 mice). (g) Histogram of the circular variance of orientation preference in individual penetrations with a silicon probe (blue, n=20) or tungsten microelectrode (red, n=37), plotted on the probability distribution generated by shuffling all recorded preferences over all penetrations (grey). (h) Median circular variance for the real penetrations (arrow) lies far below medians for shuffled data.