Abstract
Visual Area V4 is located in the ventral visual pathway and contains functional domains with different feature preference (Tanigawa et al. 2010). Many electrophysiological papers have shown that the neuronal activity in V4 can be modulated by selective attention. fMRI studies have also shown increase in BOLD activation associated with spatial attention. However little is known about how domain specific activation in V4 is affected by attention. Here we use intrinsic signal optical imaging method to address this question. Using intrinsic signal optical imaging through chronic implanted windows we observed V4 activation in Macaque monkeys performing a covert color-change detection task. In Task1 (Fig. 1a), the monkey was required to detect a subtle color change in one of two gratings (attention in vs. attention out) and to report the direction of color change (from magenta to bluish or to reddish) by making a saccade to one of two targets. In Task2 (Fig. 1b), the monkey was required report the simultaneous change of color and orientation in one grating (attention in vs. passive). In both tasks, when compared to V4 activation during spatially localized change detection (Task1) or when compared to simple fixation of a blank screen (Task2), we found (1) no significant enhancement in domain specific activation magnitude and (2) significant enhancement of domain-domain correlation across stimulus-activated domains (Fig. 2). Further analysis revealed such correlation enhancement during successful trials but not during error trials. In conclusion, utilizing intrinsic signal optical imaging we observed an attention mediated correlation enhancement among the stimulus-activated domains in V4 during change detection task. We propose that directed attention to different locations in space is mediated by magnitude enhancement (Tanigawa et al. Submitted), while attention to feature-related changes is achieved by enhancement of task-related domain-domain correlation in V4.
Meeting abstract presented at VSS 2016