title: Temporal dynamics of visual working memory.
abstract: The involvement of the human cerebellum in working memory has been well established in the last decade. However, the cerebro-cerebellar network for visual working memory is not as well defined. Our previous fMRI study showed superior and inferior cerebellar activations during a block design visual working memory task, but specific cerebellar contributions to cognitive processes in encoding, maintenance and retrieval have not yet been established. The current study examined cerebellar contributions to each of the components of visual working memory and presence of cerebellar hemispheric laterality was investigated. 40 young adults performed a Sternberg visual working memory task during fMRI scanning using a parametric paradigm. The contrast between high and low memory load during each phase was examined. We found that the most prominent activation was observed in vermal lobule VIIIb and bilateral lobule VI during encoding. Using a quantitative laterality index, we found that left-lateralized activation of lobule VIIIa was present in the encoding phase. In the maintenance phase, there was bilateral lobule VI and right-lateralized lobule VIIb activity. Changes in activation in right lobule VIIIa were present during the retrieval phase. The current results provide evidence that superior and inferior cerebellum contributes to visual working memory, with a tendency for left-lateralized activations in the inferior cerebellum during encoding and right-lateralized lobule VIIb activations during maintenance. The results of the study are in agreement with Baddeley's multi-component working memory model, but also suggest that stored visual representations are additionally supported by maintenance mechanisms that may employ verbal coding.
authors.affiliation: Division of Psychology, Nanyang Technological University, Singapore.
authors.forename: M
authors.initials: M
authors.lastname: Sobczak-Edmans
authors.affiliation: Division of Psychology, Nanyang Technological University, Singapore.
authors.forename: T H B
authors.initials: THB
authors.lastname: Ng
authors.affiliation: Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Division of Neurology, National University Hospital, National University Health System, Singapore.
authors.forename: Y C
authors.initials: YC
authors.lastname: Chan
authors.affiliation: Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Division of Neurology, National University Hospital, National University Health System, Singapore.
authors.forename: E
authors.initials: E
authors.lastname: Chew
authors.affiliation: The Queensland Brain Institute, The University of Queensland, Australia; The Centre for Advanced Imaging, The University of Queensland, Australia.
authors.forename: K H
authors.initials: KH
authors.lastname: Chuang
authors.affiliation: Division of Psychology, Nanyang Technological University, Singapore; Centre for Research and Development in Learning, Nanyang Technological University, Singapore. Electronic address: annabelchen@ntu.edu.sg.
authors.forename: S H A
authors.initials: SHA
authors.lastname: Chen
mesh_terms: D002531:Cerebellum / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D011939:Mental Recall / Q000502:physiology; D008959:Models, Neurological; D010100:Oxygen / Q000097:blood; D011597:Psychomotor Performance / Q000502:physiology; D065852:Spatial Memory / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: Cerebellum; Cognition; Visuospatial sketchpad; Working memory