Activation patterns in visual cortex reveal receptive field size-dependent attentional modulation

Because our brain cannot process all visual information that enters it, we usually pay attention to only a specific aspect of our visual world. Selective visual attention modulates brain activation in cortical areas corresponding to the attended spatial location. However, visual attention has also been associated with the modulation of activation in different brain areas depending on the relevant spatial scale. In this study, we establish a link between attended spatial scale and receptive field size. We demonstrate that attention to a large or a small object in a visual scene increases activation specifically in brain regions with correspondingly large or small receptive field sizes. To analyze and visualize differential brain activation in contiguous cortical areas we used a mapping strategy evaluating the modelling parameters (beta) from functional magnetic resonance imaging data analysis. Assessment of the course of these parameters along traces in different directions in the visual cortex strengthens our conclusion that selective visual attention modulates brain areas with specific neuronal receptive field size properties corresponding to the task at hand. This also confirms predictions of models of selective attention, that attentional modulation of visual processing critically depends on the receptive field size of neurons across the visual cortex. (c) 2007 Elsevier B.V. All rights reserved.