Fig. 2.

Small cells are diverse in their tuning to peripheral spike timing differences. Shown are raster plots (left) and smoothed tuning curves (right) from representative long-pass small cells (A) that responded preferentially to longer square-pulse durations, band-pass small cells (B) that responded preferentially to intermediate durations, and band-stop small cells (C) that responded preferentially to long and short durations. Rasters show spike times in response to 20 sweeps of each stimulus for both monophasic negative (left portion of raster) and positive (right portion of raster) stimuli (gray horizontal shading indicates durations not tested). Time is relative to stimulus onset. Responses were quantified as the mean number of spikes above baseline per stimulus repetition. The resulting data points (open circles on tuning curves at right) were then scaled to the maximum value within the unit and smoothed (black). In each case, smoothed tuning curves from 2 additional units of the same tuning type (light and dark gray) are also shown. The duration tuning curves are plotted on 2 axes, 1 on the left for negative polarity and 1 on the right for positive polarity, with the x-axis of the negative polarity plot reversed (stimulus duration increases to the left). Together, the 2 plots can be viewed as sharing a single x-axis that represents the relative timing of upward and downward stimulus edges. Background shading on tuning curves indicates the behaviorally relevant range of durations (Lyons-Warren et al. 2012). D: tuning curves (not normalized) of example units that changed tuning with changes in intensity (left) and polarity (left and right).