Representation of visual numerosity information during working memory in humans: An fMRI decoding study

• Main Authors: Blankenburg, F. (Author), Pennock, I.M.L (Author), Schmidt, T.T (Author), Zorbek, D. (Author)
• Format: Article
• Language: English
• Published: John Wiley and Sons Inc 2021
• Subjects: adult; Adult; article; brain mapping; Brain Mapping; clinical article; controlled study; decoding; diagnostic imaging; dissociation; female; Female; fMRI; functional magnetic resonance imaging; human; human experiment; Humans; intraparietal sulcus; Magnetic Resonance Imaging; male; Male; Mathematical Concepts; mathematical phenomena; Memory, Short-Term; MVPA; nuclear magnetic resonance imaging; numerosity; parietal lobe; Parietal Lobe; pattern recognition; Pattern Recognition, Visual; physiology; prefrontal cortex; short term memory; short-term memory; vision; working memory; young adult; Young Adult
• Online Access: View Fulltext in Publisher

 Both animal and human studies on numerosity have shown the importance of the parietal cortex for numerosity processing. However, most studies have focused on the perceptual processing of numerosity. Still, it is unclear how and where numerosity information is coded when this information is retained during a working memory delay phase. Such temporal storage could be realized by the same structures as perceptual processes, or be transformed to a more abstract representation, potentially involving prefrontal regions. FMRI decoding studies allow the identification of brain areas that exhibit multi-voxel activation patterns specific to the content of working memory. Here, we used an assumption-free searchlight-decoding approach to test where numerosity-specific codes can be found during a 12 s retention period. Participants (n = 24) performed a retro-cue delayed match-to-sample task, in which numerosity information was presented as visual dot arrays. We found mnemonic numerosity-specific activation in the right lateral portion of the intraparietal sulcus; an area well-known for perceptual processing of numerosity. The applied retro-cue design dissociated working memory delay activity from perceptual processes and showed that the intraparietal sulcus also maintained working memory representation independent of perception. © 2021 The Authors. Human Brain Mapping published by Wiley Periodicals LLC.