title: Attentional modulations related to spatial gating but not to allocation of limited resources in primate V1.
abstract: Attention can modulate neural responses in sensory cortical areas and improve behavioral performance in perceptual tasks. However, the nature and purpose of these modulations remain under debate. Here we used voltage-sensitive dye imaging (VSDI) to measure V1 population responses while monkeys performed a difficult detection task under focal or distributed attention. We found that V1 responses at attended locations are significantly elevated relative to actively ignored or irrelevant locations, consistent with the hypothesis that an important goal of attention in V1 is to highlight task-relevant information. Surprisingly, these modulations were indistinguishable under focal and distributed attention, suggesting a minor or no role for attention as a mechanism for allocating limited representational resources in V1. The response elevation at attended locations is additive, is widespread, and starts shortly before stimulus onset. This elevation could contribute to spatial gating by biasing competition in subsequent processing stages in favor of attended stimuli.
authors.affiliation: Center for Perceptual Systems, Department of Psychology and Section of Neurobiology, University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: Yuzhi
authors.initials: Y
authors.lastname: Chen
authors.forename: Eyal
authors.initials: E
authors.lastname: Seidemann
mesh_terms: D000818:Animals; D001288:Attention / Q000502:physiology*; D001931:Brain Mapping; D000882:Haplorhini; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D010100:Oxygen / Q000097:blood; D010775:Photic Stimulation; D055139:Sensory Gating / Q000502:physiology*; D013028:Space Perception / Q000502:physiology*; D014793:Visual Cortex / Q000098:blood supply / Q000502:physiology*; D056969:Voltage-Sensitive Dye Imaging / Q000379:methods
chemical_list: D010100:Oxygen