Stimulus expectancy modulates inferior frontal gyrus and premotor cortex activity in auditory perception

Research Area: Research Year: 2012
Type of Publication: Article Keywords: Auditory perception; Phonetic; Non-phonetic; Instruction effects; Task confounds; fMRI
Authors: Osnes, Berge; Hugdahl, Kenneth; Hjelmervik, Helene; Specht, Karsten
In studies on auditory speech perception, participants are often asked to perform active tasks, e.g. decide whether the perceived sound is a speech sound or not. However, information about the stimulus, inherent in such tasks, may induce expectations that cause altered activations not only in the auditorycortex, but also in frontal areas such as inferiorfrontalgyrus (IFG) and motor cortices, even in the absence of an explicit task. To investigate this, we applied spectral mixes of a flute sound and either vowels or specific music instrument sounds (e.g. trumpet) in an fMRI study, in combination with three different instructions. The instructions either revealed no information about stimulus features, or explicit information about either the music instrument or the vowel features. The results demonstrated that, besides an involvement of posterior temporal areas, stimulusexpectancy modulated in particular a network comprising IFG and premotorcortices during this passive listening task.
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