Abstract
Visual behavior in primates is dominated by moving the eyes (more specifically the fovea) to objects of interest. Representing the most central part of visual space, the fovea is crucial for providing high spatial acuity needed for tasks such as reading, form identification, face recognition, and is key to natural visual attentional behavior. In early visual cortex, cortical representation disproportionately represents the fovea. However, beyond this, surprisingly little is known about its cortical representation (e.g. neurophysiological data comes primarily from extra-foveal cortex). We hypothesize that, given the known specialized functions performed by the fovea, there should be differences in foveal vs extra-foveal cortical organization. This thinking is based on studies which suggest that the unique functional organizations present in V1, V2, and V4 enable different integrative capabilities within those areas, thereby resulting in area-specific functionalities. To examine this hypothesis, we have conducted optical imaging in the region of the foveal confluence in awake and anesthetized macaque monkeys. We predict differences in the organization (either qualitative or quantitative) of ocular dominance, orientation, color, disparity, and motion in foveal vs extra-foveal cortex. We consider the possibility that at the foveal confluence there are no clear borders (i.e. retintopic reversals) between cortical areas and that the foveal confluence is structured as a single specialized cortical region shared by V1, V2, and V4. Also, given the lack of blue cone representation in the foveal retina, we examine whether there is blue color representation in foveal V1, V2, and V4. It may also be possible to address the question of whether V3 extends to the foveal confluence. Thus far, our preliminary data suggest that ocular dominance columns may be less regularly organized and wider in foveal regions of V1 and that there may be a lack of strong representation of blue in the foveal confluence.
Meeting abstract presented at VSS 2013