The results above suggested that the figure-ground measure can be related to contour perception; however, the exact spatial relation, at the pixel level, is not clear. We therefore wanted to investigate the relationship between the monkey’s report and each pixel response in the imaged area. To do this, we computed the
correlation between each pixel’s population response for each orientation jitter (rather than circle and background differences) and the psychometric curve. The resulting maps show the pixel-psychometric correlation. Figure 7A shows that the pixels’ responses in the circle area were positively correlated with the contour-detection performance, whereas the pixels’ responses in the background area were negatively correlated with the contour detection. It is possible that the population response is affected directly by the orientation changes of the circle elements in the jittering conditions; however, there are few MK-8776 clinical trial arguments against this notion. First, although the contour’s elements were changed in the different jitters, the background elements were kept identical across all jitters. Nevertheless, the suppression in the background increased with contour saliency and also with animals’ contour-detection report. Namely, the population response in the background varied with the animal report in the
absence of stimulus changes Baf-A1 in the background. Second, the spatial map of correlation between the pixel response and PAK6 the behavioral performance (Figure 7A) enables to observe all the pixels in the imaged area. As one can see from the map, the correlation extends beyond the retinotopic representation of individual Gabors comprising the circle or background in V1. This is different from what one would have expected from “pure” stimulus preference. In fact, the correlation maps show a rather homogeneous distribution of positive correlation in the circle area and negative correlation in the background area. The correlation extends
over the “whole” circle and background areas, thus resulting in the impression that the entire imaged contour representation is positively correlated with behavior and that the entire imaged background representation is negatively correlated with behavior. In addition the correlation dynamics (Figure 7C) shows relatively late onset, peaking at the late phase. It was previously shown that responses to orientation in V1 appear much earlier in time, and specifically orientation maps in the VSD signal emerge much earlier in time (Sharon and Grinvald, 2002). These observations do not fit well with responses to stimulus preference alone. Finally, when presenting a naive animal with a contour embedded in a noisy background, the population response does not show similar patterns: an increased activity in the contour and decreased activity in the background (Figure S3).
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