title: Reactive cognitive-control processes in free-report consonant-vowel dichotic listening.
abstract: The relevance of cognitive-control processes has been frequently discussed and studied in the context of dichotic listening. Experimental and clinical studies indicate that directing attention to either of the two simultaneously presented phonological stimuli, but especially to the left-ear stimulus increases the requirements for cognitive-control processes. Here, we extend this view by reporting the results of a behavioural and a functional magnetic-resonance imaging (fMRI) experiment designed to analyse the involvement of cognitive-control processes also in a free-report dichotic-listening paradigm. It was hypothesised that dichotically presented pairs of stop-consonant-vowel syllables would provide different demands for cognitive-control processes as a function of the spectro-temporal overlap of the two stimuli. Accordingly, in Experiment 1 it was shown that dichotic syllables of high (e.g., /ba/ and /ga/) as opposed to low spectro-temporal overlap (e.g., /ba/ and /ka/) produce significantly faster and more correct answers, and are more often perceived as one syllable. In Experiment 2 it was further shown that pairs of low as compared to high spectro-temporal overlap trigger a more pronounced activation predominately in left-hemispheric, speech-associated brain regions, namely left posterior inferior sulcus/gyrus, bilaterally in pre-supplementary motor and mid-cingulate cortex as well as in the inferior parietal lobe. Taken together, behavioural and functional data indicate a stronger involvement of reactive cognitive control in the processing of low-overlap as opposed to high-overlap stimulus pairs. This supports the notion that higher-order, speech-related cognitive-control processes also are involved in a free-report dichotic-listening paradigm.
authors.affiliation: Department of Biological and Medical Psychology, University of Bergen, Norway; Division of Psychiatry, Haukeland University Hospital, Bergen, Norway. Electronic address: rene.westerhausen@psybp.uib.no.
authors.forename: René
authors.initials: R
authors.lastname: Westerhausen
authors.forename: Susanne
authors.initials: S
authors.lastname: Passow
authors.forename: Kristiina
authors.initials: K
authors.lastname: Kompus
mesh_terms: D000293:Adolescent; D000328:Adult; D002540:Cerebral Cortex / Q000502:physiology*; D004007:Dichotic Listening Tests; D056344:Executive Function / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D059907:Functional Neuroimaging / Q000379:methods*; D006179:Gyrus Cinguli / Q000502:physiology; D006801:Humans; D007266:Inhibition, Psychological; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010296:Parietal Lobe / Q000502:physiology; D017397:Prefrontal Cortex / Q000502:physiology; D013067:Speech Perception / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult
keywords: Cognitive control; Dichotic listening; Inhibition; Speech perception; fMRI