title: Activation lateralization in human core, belt, and parabelt auditory fields with unilateral deafness compared to normal hearing.
abstract: We studied activation magnitudes in core, belt, and parabelt auditory cortex in adults with normal hearing (NH) and unilateral hearing loss (UHL) using an interrupted, single-event design and monaural stimulation with random spectrographic sounds. NH patients had one ear blocked and received stimulation on the side matching the intact ear in UHL. The objective was to determine whether the side of deafness affected lateralization and magnitude of evoked blood oxygen level-dependent responses across different auditory cortical fields (ACFs). Regardless of ear of stimulation, NH showed larger contralateral responses in several ACFs. With right ear stimulation in UHL, ipsilateral responses were larger compared to NH in core and belt ACFs, indicating neuroplasticity in the right hemisphere. With left ear stimulation in UHL, only posterior core ACFs showed larger ipsilateral responses, suggesting that most ACFs in the left hemisphere had greater resilience against reduced crossed inputs from a deafferented right ear. Parabelt regions located posterolateral to core and belt auditory cortex showed reduced activation in UHL compared to NH irrespective of RE/LE stimulation and lateralization of inputs. Thus, the effect in UHL compared to NH differed by ACF and ear of deafness.
authors.affiliation: Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, MO 63110, USA. harold@pcg.wustl.edu
authors.forename: Harold
authors.initials: H
authors.lastname: Burton
authors.forename: Jill B
authors.initials: JB
authors.lastname: Firszt
authors.forename: Timothy
authors.initials: T
authors.lastname: Holden
authors.forename: Alvin
authors.initials: A
authors.lastname: Agato
authors.forename: Rosalie M
authors.initials: RM
authors.lastname: Uchanski
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000368:Aged; D001303:Auditory Cortex / Q000503:physiopathology*; D001931:Brain Mapping; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006309:Hearing / Q000502:physiology*; D046088:Hearing Loss, Unilateral / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009473:Neuronal Plasticity / Q000502:physiology; D009474:Neurons / Q000502:physiology