Example of the response to a white and a black bar.

<p>PSTH and raster plot of a single unit (recorded at 1700 µm depth) in response to white and black bars swept through the receptive field in the preferred direction. The upper row shows the responses to a 0.5, 1, 2 or 4 degrees wide white bar while the lower row shows the responses to a similar-sized black bar. This neuron responds almost as strong to a small white stimulus as to a large black stimulus.