Joint WCHN-ICN seminar: Mitchell Valdes-Sosa

It is well-known that the two cerebral hemispheres have different specializations for spatial scale, with the right side preferring global aspects and low spatial frequencies and the left side preferring local aspects and higher spatial frequencies. Although explanations of this specialization at an algorithmic level have been advanced, we do not have yet have a clear neurocomputational account. By using special stimulation techniques, we uncover additional evidence for this specialization, pinpointing it to the visual extra-striate cortices. By leveraging large public databases, we show that for intermediate and higher-order visual cortices, population receptive fields (pRFS) are larger on the right than in the left hemisphere, and also have lower preferred spatial frequencies, asymmetries not found in early visual areas. Simulations with a convolutional neural network model gives a proof of concept that these asymmetries in pRF size and spatial frequency selectivity, could provide a mechanism for lateralization of attention to spatial scale. We argue that we now have the experimental and theoretical tools for explaining the cerebral lateralization of attention. 

Please contact ion.fil.brainmeetings@ucl.ac.uk for a Zoom link.