title: Nonverbal sound processing in semantic dementia: a functional MRI study.
abstract: Semantic dementia (SD) is a unique neurodegenerative syndrome accompanied by relatively selective loss of the meaning of objects and concepts. The brain mechanisms that underpin the syndrome have not been defined: a better understanding of these mechanisms would inform our understanding of both the organisation of the human semantic system and its vulnerability to neurodegenerative disease. In this fMRI study, we investigated brain correlates of sensory object processing in nine patients with SD compared with healthy control subjects, using the paradigm of nonverbal sound. Compared with healthy controls, patients with SD showed differential activation of cortical areas surrounding the superior temporal sulcus, both for perceptual processing of spectrotemporally complex but meaningless sounds and for semantic processing of environmental sound category (animal sounds versus tool sounds). Our findings suggest that defective processing of sound objects in SD spans pre-semantic perceptual processing and semantic category formation. This disease model illustrates that antero-lateral temporal cortical mechanisms are critical for representing and differentiating sound categories. The breakdown of these mechanisms constitutes a network-level functional signature of this neurodegenerative disease.
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.forename: Gerard R
authors.initials: GR
authors.lastname: Ridgway
authors.forename: Sebastian J
authors.initials: SJ
authors.lastname: Crutch
authors.forename: Frederic E
authors.initials: FE
authors.lastname: Theunissen
authors.forename: Jason D
authors.initials: JD
authors.lastname: Warren
mesh_terms: D000161:Acoustic Stimulation; D000368:Aged; D000818:Animals; D001303:Auditory Cortex / Q000033:anatomy & histology / Q000502:physiology; D001307:Auditory Perception / Q000502:physiology*; D005260:Female; D057174:Frontotemporal Lobar Degeneration / Q000503:physiopathology* / Q000523:psychology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000033:anatomy & histology / Q000502:physiology; D009483:Neuropsychological Tests; D011597:Psychomotor Performance / Q000502:physiology; D013702:Temporal Lobe / Q000033:anatomy & histology / Q000502:physiology; D014828:Vocalization, Animal