title: Modality-specific perceptual expectations selectively modulate baseline activity in auditory, somatosensory, and visual cortices.
abstract: Valid expectations are known to improve target detection, but the preparatory attentional mechanisms underlying this perceptual facilitation remain an open issue. Using functional magnetic resonance imaging, we show here that expecting auditory, tactile, or visual targets, in the absence of stimulation, selectively increased baseline activity in corresponding sensory cortices and decreased activity in irrelevant ones. Regardless of sensory modality, expectancy activated bilateral premotor and posterior parietal areas, supplementary motor area as well as right anterior insula and right middle frontal gyrus. The bilateral putamen was sensitive to the modality specificity of expectations during the unexpected omission of targets. Thus, across modalities, detection improvement arising from selectively directing attention to a sensory modality appears mediated through transient changes in pretarget activity. This flexible advance modulation of baseline activity in sensory cortices resolves ambiguities among previous studies unable to discriminate modality-specific preparatory activity from attentional modulation of stimulus processing. Our results agree with predictive-coding models, which suggest that these expectancy-related changes reflect top-down biases--presumably originating from the observed supramodal frontoparietal network--that modulate signal-detection sensitivity by differentially modifying background activity (i.e., noise level) in different input channels. The putamen appears to code omission-related Bayesian "surprise" that depends on the specificity of predictions.
authors.affiliation: Department of Psychiatry, Psychotherapy and Psychosomatics, Medical School, RWTH Aachen University, 52074 Aachen, Germany. robert.langner@rwth-aachen.de
authors.forename: Robert
authors.initials: R
authors.lastname: Langner
authors.forename: Thilo
authors.initials: T
authors.lastname: Kellermann
authors.forename: Frank
authors.initials: F
authors.lastname: Boers
authors.forename: Walter
authors.initials: W
authors.lastname: Sturm
authors.forename: Klaus
authors.initials: K
authors.lastname: Willmes
authors.forename: Simon B
authors.initials: SB
authors.lastname: Eickhoff
mesh_terms: D059031:Anticipation, Psychological / Q000502:physiology*; D001288:Attention / Q000502:physiology; D001303:Auditory Cortex / Q000502:physiology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D011930:Reaction Time / Q000502:physiology; D013003:Somatosensory Cortex / Q000502:physiology*; D014793:Visual Cortex / Q000502:physiology*; D055815:Young Adult