title: Functional neuroanatomy of auditory scene analysis in Alzheimer's disease.
abstract: Auditory scene analysis is a demanding computational process that is performed automatically and efficiently by the healthy brain but vulnerable to the neurodegenerative pathology of Alzheimer's disease. Here we assessed the functional neuroanatomy of auditory scene analysis in Alzheimer's disease using the well-known 'cocktail party effect' as a model paradigm whereby stored templates for auditory objects (e.g., hearing one's spoken name) are used to segregate auditory 'foreground' and 'background'. Patients with typical amnestic Alzheimer's disease (n = 13) and age-matched healthy individuals (n = 17) underwent functional 3T-MRI using a sparse acquisition protocol with passive listening to auditory stimulus conditions comprising the participant's own name interleaved with or superimposed on multi-talker babble, and spectrally rotated (unrecognisable) analogues of these conditions. Name identification (conditions containing the participant's own name contrasted with spectrally rotated analogues) produced extensive bilateral activation involving superior temporal cortex in both the AD and healthy control groups, with no significant differences between groups. Auditory object segregation (conditions with interleaved name sounds contrasted with superimposed name sounds) produced activation of right posterior superior temporal cortex in both groups, again with no differences between groups. However, the cocktail party effect (interaction of own name identification with auditory object segregation processing) produced activation of right supramarginal gyrus in the AD group that was significantly enhanced compared with the healthy control group. The findings delineate an altered functional neuroanatomical profile of auditory scene analysis in Alzheimer's disease that may constitute a novel computational signature of this neurodegenerative pathology.
authors.affiliation: Dementia Research Centre, UCL Institute of Neurology, University College London, London, UK.
authors.forename: Hannah L
authors.initials: HL
authors.lastname: Golden
authors.affiliation: Dementia Research Centre, UCL Institute of Neurology, University College London, London, UK.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Agustus
authors.affiliation: Dementia Research Centre, UCL Institute of Neurology, University College London, London, UK.
authors.forename: Johanna C
authors.initials: JC
authors.lastname: Goll
authors.affiliation: Dementia Research Centre, UCL Institute of Neurology, University College London, London, UK.
authors.forename: Laura E
authors.initials: LE
authors.lastname: Downey
authors.affiliation: Dementia Research Centre, UCL Institute of Neurology, University College London, London, UK.
authors.forename: Catherine J
authors.initials: CJ
authors.lastname: Mummery
authors.affiliation: Dementia Research Centre, UCL Institute of Neurology, University College London, London, UK.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Schott
authors.affiliation: Dementia Research Centre, UCL Institute of Neurology, University College London, London, UK.
authors.forename: Sebastian J
authors.initials: SJ
authors.lastname: Crutch
authors.affiliation: Dementia Research Centre, UCL Institute of Neurology, University College London, London, UK.
authors.forename: Jason D
authors.initials: JD
authors.lastname: Warren
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000503:physiopathology*; D001301:Audiometry, Pure-Tone; D001307:Auditory Perception; D001308:Auditory Perceptual Disorders / Q000503:physiopathology*; D001921:Brain / Q000503:physiopathology; D001931:Brain Mapping; D016022:Case-Control Studies; D005260:Female; D059907:Functional Neuroimaging; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010296:Parietal Lobe / Q000503:physiopathology*; D059629:Signal-To-Noise Ratio; D013067:Speech Perception; D013702:Temporal Lobe / Q000503:physiopathology*
keywords: Alzheimer's disease; Auditory scene analysis; Cocktail party effect; fMRI