title: Attentional enhancement via selection and pooling of early sensory responses in human visual cortex.
abstract: The computational processes by which attention improves behavioral performance were characterized by measuring visual cortical activity with functional magnetic resonance imaging as humans performed a contrast-discrimination task with focal and distributed attention. Focal attention yielded robust improvements in behavioral performance accompanied by increases in cortical responses. Quantitative analysis revealed that if performance were limited only by the sensitivity of the measured sensory signals, the improvements in behavioral performance would have corresponded to an unrealistically large reduction in response variability. Instead, behavioral performance was well characterized by a pooling and selection process for which the largest sensory responses, those most strongly modulated by attention, dominated the perceptual decision. This characterization predicts that high-contrast distracters that evoke large responses should negatively impact behavioral performance. We tested and confirmed this prediction. We conclude that attention enhanced behavioral performance predominantly by enabling efficient selection of the behaviorally relevant sensory signals.
authors.affiliation: Gardner Research Unit, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama 315-0198, Japan. fp2190@brain.riken.jp
authors.forename: Franco
authors.initials: F
authors.lastname: Pestilli
authors.forename: Marisa
authors.initials: M
authors.lastname: Carrasco
authors.forename: David J
authors.initials: DJ
authors.lastname: Heeger
authors.forename: Justin L
authors.initials: JL
authors.lastname: Gardner
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D001931:Brain Mapping; D002755:Choice Behavior / Q000502:physiology*; D015350:Contrast Sensitivity / Q000502:physiology*; D003463:Cues; D004192:Discrimination, Psychological / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D015233:Models, Statistical; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood; D010775:Photic Stimulation; D011601:Psychophysics; D011930:Reaction Time; D014793:Visual Cortex / Q000098:blood supply / Q000502:physiology*
chemical_list: D010100:Oxygen