Cortico-Cortical Receptive Field Estimates in Human Visual Cortex

Abstract

Human visual cortex comprises many visual areas that contain a map of the visual field (Wandell et al 2007, Neuron56, 366–383). These visual field maps can be identified readily in individual subjects with functional magnetic resonance imaging (fMRI) during experimental sessions that last less than an hour (Wandell and Winawer 2011, Vis Res 718–737). Hence, visual field mapping with fMRI has been, and still is, a heavily used technique to examine the organisation of both normal and abnormal human visual cortex (Haak et al 2011, ACNR, 11(3), 20–21). However, visual field mapping cannot reveal every aspect of human visual cortex organisation. For example, the information processed within a visual field map arrives from somewhere and is sent to somewhere, and visual field mapping does not derive these input/output relationships. Here, we describe a new, model-based analysis for estimating the dependence between signals in distinct cortical regions using functional magnetic resonance imaging (fMRI) data. Just as a stimulus-referred receptive field predicts the neural response as a function of the stimulus contrast, the neural-referred receptive field predicts the neural response as a function of responses elsewhere in the nervous system. When applied to two cortical regions, this function can be called the cortico-cortical receptive field (CCRF). We model the CCRF as a Gaussian-weighted region on the cortical surface and apply the model to data from both stimulus-driven and resting-state experimental conditions in visual cortex.