title: Brain activity during the encoding, retention, and retrieval of stimulus representations.
abstract: Studies of delayed nonmatching-to-sample (DNMS) performance following lesions of the monkey cortex have revealed a critical circuit of brain regions involved in forming memories and retaining and retrieving stimulus representations. Using event-related functional magnetic resonance imaging (fMRI), we measured brain activity in 10 healthy human participants during performance of a trial-unique visual DNMS task using novel barcode stimuli. The event-related design enabled the identification of activity during the different phases of the task (encoding, retention, and retrieval). Several brain regions identified by monkey studies as being important for successful DNMS performance showed selective activity during the different phases, including the mediodorsal thalamic nucleus (encoding), ventrolateral prefrontal cortex (retention), and perirhinal cortex (retrieval). Regions showing sustained activity within trials included the ventromedial and dorsal prefrontal cortices and occipital cortex. The present study shows the utility of investigating performance on tasks derived from animal models to assist in the identification of brain regions involved in human recognition memory.
authors.affiliation: Centre for Magnetic Resonance, The University of Queensland, St. Lucia QLD 4072, Australia. greig.dezubicaray@cmr.uq.edu.au
authors.forename: G I
authors.initials: GI
authors.lastname: de Zubicaray
authors.forename: K
authors.initials: K
authors.lastname: McMahon
authors.forename: S J
authors.initials: SJ
authors.lastname: Wilson
authors.forename: S
authors.initials: S
authors.lastname: Muthiah
mesh_terms: D000328:Adult; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology*; D002540:Cerebral Cortex / Q000033:anatomy & histology / Q000502:physiology; D003071:Cognition / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008568:Memory / Q000502:physiology*; D010775:Photic Stimulation