title: Hand placement near the visual stimulus improves orientation selectivity in V2 neurons.
abstract: Often, the brain receives more sensory input than it can process simultaneously. Spatial attention helps overcome this limitation by preferentially processing input from a behaviorally-relevant location. Recent neuropsychological and psychophysical studies suggest that attention is deployed to near-hand space much like how the oculomotor system can deploy attention to an upcoming gaze position. Here we provide the first neuronal evidence that the presence of a nearby hand enhances orientation selectivity in early visual processing area V2. When the hand was placed outside the receptive field, responses to the preferred orientation were significantly enhanced without a corresponding significant increase at the orthogonal orientation. Consequently, there was also a significant sharpening of orientation tuning. In addition, the presence of the hand reduced neuronal response variability. These results indicate that attention is automatically deployed to the space around a hand, improving orientation selectivity. Importantly, this appears to be optimal for motor control of the hand, as opposed to oculomotor mechanisms which enhance responses without sharpening orientation selectivity. Effector-based mechanisms for visual enhancement thus support not only the spatiotemporal dissociation of gaze and reach, but also the optimization of vision for their separate requirements for guiding movements.
authors.affiliation: Visual Perception and Attention Laboratory, School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada; Centre for Vision Research, York University, Toronto, Ontario, Canada; School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada; carolynperry08@gmail.com.
authors.forename: Carolyn J
authors.initials: CJ
authors.lastname: Perry
authors.affiliation: Centre for Vision Research, York University, Toronto, Ontario, Canada; School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada;
authors.forename: Lauren E
authors.initials: LE
authors.lastname: Sergio
authors.affiliation: Centre for Vision Research, York University, Toronto, Ontario, Canada; Department of Psychology, York University, Toronto, Ontario, Canada; and Canadian Action and Perception Network, York University, Toronto, Ontario, Canada.
authors.forename: J Douglas
authors.initials: JD
authors.lastname: Crawford
authors.affiliation: Visual Perception and Attention Laboratory, School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada; Centre for Vision Research, York University, Toronto, Ontario, Canada; School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada; Canadian Action and Perception Network, York University, Toronto, Ontario, Canada.
authors.forename: Mazyar
authors.initials: M
authors.lastname: Fallah
mesh_terms: D000818:Animals; D001288:Attention / Q000502:physiology; D003463:Cues; D005260:Female; D006225:Hand / Q000502:physiology*; D008253:Macaca mulatta; D009949:Orientation / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods*; D011187:Posture / Q000502:physiology*; D011984:Sensory Receptor Cells / Q000502:physiology*; D013028:Space Perception / Q000502:physiology; D013647:Task Performance and Analysis; D014793:Visual Cortex / Q000502:physiology*
keywords: attention; peripersonal space; reaching; vision