title: Neuroimaging the short- and long-term effects of repeated picture naming in healthy older adults.
abstract: Repeated attempts to name pictures can improve subsequent naming for aphasic individuals with anomia, however, the neurocognitive mechanisms responsible for such improvements are unknown. This study investigated repeated picture naming in healthy older adults over a period of minutes (short-term) after one repetition and a period of days (long-term) after multiple repetitions. Compared to unprimed pictures, both repeated conditions showed faster naming latencies with the fastest latencies evident for the short-term condition. Neuroimaging results identified repetition suppression effects across three left inferior frontal gyrus regions of interest: for both the short- and long-term conditions in the pars orbitalis, and for long-term items in the pars triangularis and pars opercularis regions. The whole brain analysis also showed a repetition suppression effect in bilateral pars triangularis regions for the long-term condition. These findings within the inferior frontal gyrus suggest that effects of repeated naming may be driven by a mapping mechanism across multiple levels of representation, possibly reflecting different levels of learning, and lend support to the idea that processing may be hierarchically organised in the left inferior frontal gyrus. The whole brain analysis also revealed repetition suppression for the long-term condition within the posterior portion of bilateral inferior temporal gyri, which may reflect attenuation of integration processes within this region following the learning of task-relevant information.
authors.affiliation: The University of Queensland, UQ Centre for Clinical Research, Brisbane, Australia; NHMRC Centre for Clinical Research Excellence in Aphasia Rehabilitation, Australia. Electronic address: MacDonald-annadmac@gmail.com.
authors.forename: Anna D
authors.initials: AD
authors.lastname: MacDonald
authors.affiliation: Macquarie University, ARC Centre of Excellence in Cognition and its Disorders, Department of Cognitive Science, Sydney, Australia. Electronic address: Heath-shiree.heath@mq.edu.au.
authors.forename: Shiree
authors.initials: S
authors.lastname: Heath
authors.affiliation: The University of Queensland, Centre for Advanced Imaging, Brisbane, Australia. Electronic address: McMahon-katie.mcmahon@cai.uq.edu.au.
authors.forename: Katie L
authors.initials: KL
authors.lastname: McMahon
authors.affiliation: NHMRC Centre for Clinical Research Excellence in Aphasia Rehabilitation, Australia; Macquarie University, ARC Centre of Excellence in Cognition and its Disorders, Department of Cognitive Science, Sydney, Australia. Electronic address: Nickels-lyndsey.nickels@mq.edu.au.
authors.forename: Lyndsey
authors.initials: L
authors.lastname: Nickels
authors.affiliation: NHMRC Centre for Clinical Research Excellence in Aphasia Rehabilitation, Australia; The University of Queensland, School of Health and Rehabilitation Sciences, Division of Speech Pathology, Brisbane, Australia. Electronic address: Angwin-a.angwin@uq.edu.au.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Angwin
authors.affiliation: The University of Queensland, UQ Centre for Clinical Research, Brisbane, Australia; NHMRC Centre for Clinical Research Excellence in Aphasia Rehabilitation, Australia; The University of Queensland, School of Health and Rehabilitation Sciences, Division of Speech Pathology, Brisbane, Australia. Electronic address: svanhees@ucalgary.ca.
authors.forename: Sophia
authors.initials: S
authors.lastname: van Hees
authors.affiliation: The University of Queensland, Centre for Advanced Imaging, Brisbane, Australia. Electronic address: Johnson-k.johnson1@uq.edu.au.
authors.forename: Kori
authors.initials: K
authors.lastname: Johnson
authors.affiliation: The University of Queensland, UQ Centre for Clinical Research, Brisbane, Australia; NHMRC Centre for Clinical Research Excellence in Aphasia Rehabilitation, Australia; The University of Queensland, School of Health and Rehabilitation Sciences, Division of Speech Pathology, Brisbane, Australia. Electronic address: Copland-d.copland@uq.edu.au.
authors.forename: David A
authors.initials: DA
authors.lastname: Copland
mesh_terms: D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D059906:Neuroimaging; D010364:Pattern Recognition, Visual / Q000502:physiology*; D021641:Recognition, Psychology / Q000502:physiology*; D060865:Repetition Priming / Q000502:physiology*
keywords: FMRI; Naming; Picture naming; Priming; Repetition suppression; Word production