Neuroscience 1995 Poster Methods


Single neurons were isolated with glass micropipettes filled with 0.2M KCl and 10% HRP, impedances ranging from ~100-200 megaohms. Visual stimuli were presented on a Tektronix 608 at a distance of 57 cm from the dominant eye at 15 candelas/meter-squared and contrasts of about 0.5. Responses are derived from 4s test trials that were preceded by 8s adapting periods. During these adapting periods either a drifting grating or a blank screen might be present, with all conditions interleaved randomly. A raster plot illustrating the responses to all of the stimuli for the experiment that provided the data shown in Figures 2-7 is shown in Figure 0. To the left of the vertical red dashed line are the 8s of adapting stimulation, and to the right are the 4s of test stimulation. All 80 conditions here were presented in an interleaved fashion, with each condition repeated 6 times. You can see that the test responses that followed the drifting grating adapting stimulus were weaker than those that followed the blank screen.

In general, test stimuli were either drifting gratings (in figure 1) or stationary bars. Single optimally oriented bars at a range of positions across the receptive field were either luminance-modulated sinusoidally in time at several temporal frequencies (as in figures 0 and 2-7), or flashed in each contrast for 40ms in a random sequence (as in figures 8-10).

Figure 0

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