We chose the spatial texture of the object and background to be identical; thus, the object was camouflaged and could only be detected by its motion. When the object moved, it stimulated the retina with both differential motion and an increase in spatiotemporal contrast; however, once the object ceased its differential motion relative to the background, it became indistinguishable from the background; thus, any information about its location could only Crizotinib concentration arise as a prediction based on prior measurements. The background stimulus consisted of vertical lines, with intensities drawn randomly from a Gaussian distribution, that jittered in

one dimension to mimic fixational drift eye movements (Olveczky et al., 2003) (Figure 7A). Every 8 s, three neighboring bars, representing an object, moved together for 250 ms at a speed of 1.1 mm/s (for a total distance

of 275 μm). This prolonged period was used only to provide a steady baseline for the measurement, as experiments changing contrast every 0.5 s (Figure 4) show that sensitization occurs even in a rapidly changing environment. Thus, the object part of the stimulus changed its spatiotemporal contrast by virtue of its changing motion—fast motion represented high contrast, and background motion represented low contrast. KU 57788 We measured the responses of the different populations of ganglion cells to the camouflaged object at many different retinal locations. We computed the average firing rate of each population as a function of the distance between the cell and the center of the object’s trajectory. As expected, when the object moved, cells responded strongly in the location of the moving object (Figure 7A). After the object stopped its differential motion, disappearing into the background,

On cells decreased their activity within 0.5 mm of the object, consistent with their monophasic AFs (Figure 7B). Sensitizing cells, however, showed persistent elevated activity crotamiton in the location where the object recently moved (Figures 7A and 7B). This activity was significantly (p < 0.002) above the steady-state response for 2.8 s after the object stopped its motion relative to the background. We compared the duration of this elevated activity to the duration of the immediate response, defined as the time that cells under the moving object fell below the baseline firing rate, reflecting the end of the linear filter and the onset of brief local adaptation. Sensitizing cells showed elevated activity for 21 times longer than their immediate response to the fast motion, which was 133 ms. Thus, sensitizing cells functionally stored the location of the previously moving object with locally increased activity. Adapting Off cells had diminished activity in the immediate location where the object stopped, indicated by a distance of zero in Figure 7. However, adjacent to the location of the moving object, these cells increased their activity (Figure 7B).