Figure 7.

US rapidly modulates visual responses. a, Visual stimulus was a binary random checkerboard presented simultaneously with a 0.2 s US pulse delivered every 2 s. Spikes were analyzed relative to the visual stimulus as in Equation 1 but subdivided into three time intervals according to the US stimulus: On, during the 0.2 s US stimulus; Off, up to 0.2 s immediately after US; and Control, 0.1 s after the Off interval until the next On interval. b, Firing rate (light blue), temporal filters, and nonlinearities for three cells. Colors are indicated in a. Three example cells are shown. c, Changes in threshold and average sensitivity of the nonlinearities caused by US (n = 35). Left, Change in average sensitivity, computed as the average slope of the nonlinearity, during US On versus during Off periods. Right, Change in threshold during On period versus Off period. d, Left, Receptive fields of 35 retinal ganglion cells. Red indicates the US focus. Middle left, Total visual sensitivity across the population. For each cell, sensitivity was computed at each spatial location as the RMS value of the spatiotemporal filter at that spatial location. Total sensitivity was computed by summing across all cells. Middle right, The change in sensitivity produced by US On computed as the total sensitivity during US On minus the total sensitivity during control. Red pixels indicate a reduction and blue pixels indicate an increase in sensitivity. Right, The change in sensitivity produced by US Off. e, Change in sensitivity as a function of distance from the US focus for On (left) and Off (right) intervals. A Gaussian fit during the Off interval has an SD of 110 μm.