Abstract
Behavioral studies have demonstrated facilitated detection of targets located near the palm compared to far from the hand. This facilitation has been attributed to an integration of visual, proprioceptive and haptic inputs. Recent ERP studies have documented hand position influences on visual processing at both early N1 and later P3 components. In this study, we investigated whether proprioception without visual input of hand location contributes to these effects. In a go-nogo visual detection paradigm, participants viewed centrally presented stimuli between two occlusion panels that blocked the view of the hand. Hand position was varied so that the hand was held behind the panels, either near or far from the visual stimuli. EEG/ERP data indicated that with only proprioceptive information about hand location, N1 amplitudes were similar for both near and far hand conditions. However, near hand conditions produced larger target vs. non-target differences for P3 amplitudes than far hand conditions. This near hand advantage can be attributed to greater P3 amplitudes for targets compared to far hand conditions. These results suggest that although proprioceptive influences do not appear to have a strong effect early in processing, they are evident at later stages. Thus, visual input of the hand's location may be necessary to draw visual attention to intended-action objects ("targets" vs. "non-targets") at the N1, but proprioceptive information about hand location emerges later at the P3 to enhance visual target processing.
Meeting abstract presented at VSS 2016