title: Short-term retention of visual information: Evidence in support of feature-based attention as an underlying mechanism.
abstract: Retention of features in visual short-term memory (VSTM) involves maintenance of sensory traces in early visual cortex. However, the mechanism through which this is accomplished is not known. Here, we formulate specific hypotheses derived from studies on feature-based attention to test the prediction that visual cortex is recruited by attentional mechanisms during VSTM of low-level features. Functional magnetic resonance imaging (fMRI) of human visual areas revealed that neural populations coding for task-irrelevant feature information are suppressed during maintenance of detailed spatial frequency memory representations. The narrow spectral extent of this suppression agrees well with known effects of feature-based attention. Additionally, analyses of effective connectivity during maintenance between retinotopic areas in visual cortex show that the observed highlighting of task-relevant parts of the feature spectrum originates in V4, a visual area strongly connected with higher-level control regions and known to convey top-down influence to earlier visual areas during attentional tasks. In line with this property of V4 during attentional operations, we demonstrate that modulations of earlier visual areas during memory maintenance have behavioral consequences, and that these modulations are a result of influences from V4.
authors.affiliation: Center for the Study of Human Cognition, Department of Psychology, University of Oslo, Box 1094 Blindern, 0317 Oslo, Norway. Electronic address: m.h.sneve@psykologi.uio.no.
authors.forename: Markus H
authors.initials: MH
authors.lastname: Sneve
authors.affiliation: Helen Wills Neuroscience Institute and The Henry H. Wheeler, Jr., Brain Imaging Center, University of California, Berkeley, Berkeley, CA 94720, USA.
authors.forename: Kartik K
authors.initials: KK
authors.lastname: Sreenivasan
authors.affiliation: Center for the Study of Human Cognition, Department of Psychology, University of Oslo, Box 1094 Blindern, 0317 Oslo, Norway.
authors.forename: Dag
authors.initials: D
authors.lastname: Alnæs
authors.affiliation: Center for the Study of Human Cognition, Department of Psychology, University of Oslo, Box 1094 Blindern, 0317 Oslo, Norway.
authors.forename: Tor
authors.initials: T
authors.lastname: Endestad
authors.affiliation: Center for the Study of Human Cognition, Department of Psychology, University of Oslo, Box 1094 Blindern, 0317 Oslo, Norway.
authors.forename: Svein
authors.initials: S
authors.lastname: Magnussen
mesh_terms: D001288:Attention / Q000502:physiology*; D001931:Brain Mapping; D015350:Contrast Sensitivity / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D010775:Photic Stimulation; D014793:Visual Cortex / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*
keywords: Feature-based attention; Functional magnetic resonance imaging; Low-level visual features; Short-term memory; Visual cortex