Enhanced Attention Near the Hands: Investigating Neural Activity in Area V2

Poster Session F - Tuesday, April 16, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Hamidreza Ramezanpour¹ (hamidram@yorku.ca), Devin Heinze Kehoe¹, Carolyn Perry¹, Mazyar Fallah^1,2; ¹York University, Toronto, Ontario, Canada, ²College of Biological Science, University of Guelph, Guelph, Ontario, Canada

Behavioral studies have shown that visual processing is enhanced in space near the hand. These alterations might be a result of deploying attention to peri-hand space, like how the oculomotor system enhances visual processing at the endpoint of saccades. The underlying neural mechanisms that would drive altered visual processing near the hand are not well understood and it is not clear whether peri-hand attention might be solely due to vision of one own’s hand, proprioceptive feedback to visual cortex, or a combination of both signals. Parietal neurons integrate sources of visual and proprioceptive information for visually guided reach movements. Hence, we hypothesize that enhanced visual processing in peri-hand space is a result of feedback from parietal cortex to early visual areas. To test our hypothesis, we recorded from individual neurons in area V2 of rhesus monkeys, engaged in a passive fixation task in which an oriented bar was presented in the receptive field of neurons in the presence or absence of a nearby hand. When the hand was placed near, yet outside the receptive field, responses to the preferred orientation were significantly enhanced no matter if the hand was visible or occluded. These enhancements were diminished when the hand was far from the visual stimulus. Our findings suggest that there exist parallel effector-based mechanisms for deploying spatial attention which might ease decoupling of eye and hand movements, and the feedback signals responsible for deploying these attentional signals are proprioceptive in nature. These results have implications for attentional disorders and blindsight.

Topic Area: ATTENTION: Spatial