Intracortical recordings in human lateral occipital complex support the biased-competition model of spatial attention

Abstract Spatial attention is fundamental for prioritizing relevant information in complex visual environments. Yet, the neural mechanisms underlying this process in humans remain elusive given the spatiotemporal constraints of functional imaging. Here we present multi-unit spiking activity from the human lateral occipital complex (LO) during a covert spatial visual attention task. Spatial attention strongly modulates neural activity when multiple competing stimuli are present in the receptive field, but not when one stimulus is outside the receptive field, supporting the biased-competition model of attention. This model suggests that spatial attention reduces interference between stimuli by favoring the attended one. Additionally, we found that attention and keeping an object in working memory extends the neural representation of an object. Crucially, our study offers the first demonstration of the neural effects of spatial attention in human visual cortex and a more naturalistic insight into human visual attention, as the participants received no prior training, unlike electrophysiology studies on trained macaques. Our study bridges human neuroimaging and primate electrophysiology, providing unique insights into the neural basis of attention.