title: Neural substrates of successful working memory and long-term memory formation in a relational spatial memory task.
abstract: Working memory (WM) tasks may involve brain activation actually implicated in long-term memory (LTM). In order to disentangle these two memory systems, we employed a combined WM/LTM task, using a spatial relational (object-location) memory paradigm and analyzed which brain areas were associated with successful performance for either task using fMRI. Critically, we corrected for the performance on the respective memory task when analyzing subsequent memory effects. The WM task consisted of a delayed-match-to-sample task assessed in an MRI scanner. Each trial consisted of an indoor or outdoor scene in which the exact configuration of four objects had to be remembered. After a short delay (7-13 s), the scene was presented from a different angle and spatial recognition for two objects was tested. After scanning, participants received an unexpected subsequent recognition memory (LTM) task, where the two previously unprobed objects were tested. Brain activity during encoding, delay phase and probe phase was analyzed based on WM and LTM performance. Results showed that successful WM performance, when corrected for LTM performance, was associated with greater activation in the inferior frontal gyrus and left fusiform gyrus during the early stage of the maintenance phase. A correct decision during the WM probe was accompanied by greater activation in a wide network, including bilateral hippocampus, right superior parietal gyrus and bilateral insula. No voxels exhibited supra-threshold activity during the encoding phase, and we did not find any differential activity for correct versus incorrect trials in the WM task when comparing LTM correct versus LTM incorrect trials.
authors.affiliation: Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands.
authors.forename: Heiko C
authors.initials: HC
authors.lastname: Bergmann
authors.affiliation: Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands.
authors.forename: Sander M
authors.initials: SM
authors.lastname: Daselaar
authors.affiliation: Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands.|Department of Cognitive Neuroscience, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Guillén
authors.initials: G
authors.lastname: Fernández
authors.affiliation: Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands. r.kessels@donders.ru.nl.|Department of Medical Psychology, Radboud University Medical Center, Nijmegen, The Netherlands. r.kessels@donders.ru.nl.|Neuropsychology and Rehabilitation Psychology, Radboud University, Montessorilaan 3, 6525 HR, Nijmegen, The Netherlands. r.kessels@donders.ru.nl.
authors.forename: Roy P C
authors.initials: RP
authors.lastname: Kessels
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging / Q000502:physiology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D057567:Memory, Long-Term / Q000502:physiology*; D008570:Memory, Short-Term / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D010775:Photic Stimulation; D012691:Serial Learning / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: Episodic memory; Neuroimaging; Spatial memory; Subsequent memory; Working memory