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  • GandolfoDowningCurrBiol2019

    Accepted author manuscript, 1 MB, PDF document

    Embargo ends: 18/07/20

DOI

Expectations about a visual event shape the way it is perceived [1, 2, 3, 4]. For example, expectations induced by valid cues signaling aspects of a visual target can improve judgments about that target, relative to invalid cues [5, 6]. Such expectation effects are thought to arise via pre-activation of a template in neural populations that represent the target [7, 8] in early sensory areas [9] or in higher-level regions. For example, category cues (“face” or “house”) modulate pre-target fMRI activity in associated category-selective brain regions [10, 11]. Further, a relationship is sometimes found between the strength of template activity and success in perceptual tasks on the target [12, 13, 14]. However, causal evidence linking pre-target activity with expectation effects is lacking. Here we provide such evidence, using fMRI-guided online transcranial magnetic stimulation (TMS). In two experiments, human volunteers made binary judgments about images of either a body or a scene. Before each target image, a verbal cue validly or invalidly indicated a property of the image, thus creating perceptual expectations about it. To disrupt these expectations, we stimulated category-selective visual brain regions (extrastriate body area, EBA; occipital place area, OPA) during the presentation of the cue. Stimulation ended before the target images appeared. We found a double dissociation: TMS to EBA during the cue period removed validity effects only in the body task, whereas stimulating OPA removed validity effects only in the scene task. Perceptual expectations are expressed by the selective activation of relevant populations within brain regions that encode the target.

Keywords

  • perceptual expectations, pre-stimulus brain activity, category-selective brain regions, transcranial magnetic stimulation, extrastriate body area, occipital place area
Original languageEnglish
Pages (from-to)2496-2500
JournalCurrent Biology
Volume29
Issue number15
Early online date18 Jul 2019
DOIs
Publication statusPublished - 5 Aug 2019
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