Dynamic stabilization of receptive fields of cortical neurons (VI) during fixation of gaze in the macaque.

The positions of receptive field borders of striate cortical neurons were measured repeatedly in awake monkeys during attentive fixation of a small target. The border position, as marked by the onset of evoked activity in response to a moving stimulus, did not show the variability expected from previous measures of eye position variability during fixation. Measured variability was smaller than expected. Trial-by-trial comparisons suggest that receptive field borders are not shifted by the small eye movements occurring during attentive fixation. It is our hypothesis that attentive fixation engages a mechanism that gates incoming information to achieve a stabilization of the receptive field relative to the external world. Such a dynamic positional compensation may underlie preliminary evidence showing that the response of stereo-sensitive neurons in striate cortex is consistent with stimulus disparity measures and, within limits, does not reflect the retinal disparities produced by the changes in binocular alignment during fixation.