Abstract
In this study we determined the contrast-sign selectivity of the mechanisms involved in contour integration and terminator detection in V1 of alert macaques. The inhibitory effect of the end zones in end-stopped cells was highly selective for the relative sign of contrast between the central activating stimulus and stimuli presented to the end zone. On the other hand, the facilitatory effect of end zones in length summating cells was not selective for the relative sign of contrast between the central activating stimulus and stimuli presented to the end zone. Thus end stopping may belong more in the category of contrast-sign selective cortical computations such as direction selectivity and disparity selectivity, rather than those that arise from a non-selective cortical network, such as contrast gain control. We also confirmed that the end-stopping crosses the eyes, ruling out the possibility that it arises as early as the LGN and confirming a cortical origin for end-stopping.
Supported by NIH (EY13135)