Shift in speed selectivity of visual cortical neurons: A neural basis of perceived motion contrast

The perceived speed of motion in one part of the visual field is influenced by the speed of motion in its surrounding fields. Little is known about th e cellular mechanisms causing this phenomenon, Recordings front mammalian v isual cortex revealed that speed preference of the cortical cells could be changed by displaying a contrast speed in the field surrounding the cell's classical receptive field. The neuron's selectivity shifted to prefer faste r speed if the contextual surround motion was set at a relatively lower spe ed, and, ice versa. These specific center-surround interactions may underli e the perceptual enhancement of speed contrast between adjacent fields.