Receptive Field Maps

Responses to a narrow bar. The bar luminance was modulated sinusoidally at 5 temporal frequencies. Eight positions were tested across 2 degrees. The adapting stimulus was a 0.7cpd grating drifting in the preferred direction at 4Hz.

Figure 2 shows the control receptive field plots, and figure 3 shows the adapted plots. Note that all of these responses were obtained in interleaved trials. The calibration bars show the instantaneous firing rate in spikes per second. The bar was modulated so that it first went dark, then bright. Two cycles are shown for clarity. The cell had strong OFF and ON zones, and a weak ON zone that doesn't show up here. The hand-plot is shown below.

This cell was fairly direction selective, but as is often the case, the responses to single bars do not capture the full splendor of the receptive field. These maps are therefore only slightly inseparable (spatiotemporally oriented). However, the preferred direction is clear: downward in these plots (I aplogize for the missing minus signs and decimal points, and will see about fixing this eventually, but the labels to the left of the histograms should go from 1 degree at the top to -1 degree at the bottom, with intermediate values of plus/minus 0.7, 0.4, and 0.1 degrees).

The figures might take a minute to download, be patient if you want to inspect them. The rest of the poster will focus on the responses at 2Hz, and those histograms reappear in figure 7.

Figure 2

Figure 3

Next section is Prediction of Drifting Grating Responses.

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