Feedback interactions between peripheral and foveal regions in the primary visual cortex

Peripheral and foveal vision must interact to coordinate many important aspects of behaviour. For example, when a potential threat emerges in the periphery, quick and accurate eye movements must be initiated to quickly and accurately assess the threat with foveal vision. There is increasing evidence that the initial moments of visual perception accomplished in the periphery is not wasted by the fovea. That is, processing by the fovea at least partially incorporates preceding processing by the fovea. The best evidence for this comes from a series of studies spanning multiple methodologies and all demonstrating the existence of information in the unstimulated foveal cortex for peripheral stimuli that is (1) non-retinotopic, (2) crucial for discrimination performance, and (3) exists in a time window that is consistent with a feedback mechanism from the periphery to fovea. However, the precise anatomical and functional nature of this feedback mechanism remain largely mysterious. Is it implemented entirely in the primary visual cortex, or is it instead implemented as a connection from higher-order areas back to lower-order areas? Does it carry only low-level perceptual features or might it also carry higher level category information? In this project, we seek to shed light on these questions. In Chapter 2, we use fMRI to assess whether perceptual or categorical information about objects presented in the periphery is relayed to the fovea. In Chapter 3, we build a deep convolutional neural network models of the ventral visual processing stream - each making different assumptions about the source of feedback from periphery to fovea - and examine their ability to recapitulate the results from our fMRI study and other important results from the literature.