"Retinotopic priors for eyes and mouth in face perception and face sensitive cortex." Benjamin de Haas (University College London)
Monday, 20 October 2014, 12pm to 1pm
Visual processing in object sensitive cortex is often described as location invariant. However, single unit recordings suggest that neurons in these areas possess spatial receptive fields of varying sizes and behavioural and neuroimaging studies in humans point in a similar direction. What, if any, is the functional role of such spatial selectivity in the ventral visual stream?
I sought to investigate this question in humans using face stimuli. Gaze patterns towards faces typically concentrate on the inner features of the face and imply a retinotopic bias. Eyes appear more often in the upper than lower visual field and the reverse is true for mouths. I will present eye-tracking data confirming this bias as well as behavioral and neuroimaging data demonstrating its relevance for face processing. The behavioral data show a recognition advantage for face features presented at canonical vs. reversed stimulus locations. Similarly, the neuroimaging data suggest a correlation between spatial and feature preferences in face sensitive areas of the right hemisphere.
These results indicate face processing and gaze behaviour are tuned to each other as well as to the inherent structure of (upright) faces. They also point to a simple neural explanation for face inversion effects and to a possible cause for problems with face recognition in conditions affecting gaze behavior, such as prosopagnosia and autism.