Neural mechanisms underlying visual short-term memory gain for temporally distinct objects

Ihssen, N.; Linden, D.E.J.; Miller, C.E.; Shapiro, K.L.

Abstract

Recent research has shown that visual short-term memory (VSTM) can substantially be improved when the to-be-remembered objects are split in 2 half-arrays (i.e., sequenced) or the entire array is shown twice (i.e., repeated), rather than presented simultaneously. Here we investigate the hypothesis that sequencing and repeating displays overcomes attentional “bottlenecks” during simultaneous encoding. Using functional magnetic resonance imaging, we show that sequencing and repeating displays increased brain activation in extrastriate and primary visual areas, relative to simultaneous displays (Study 1). Passively viewing identical stimuli did not increase visual activation (Study 2), ruling out a physical confound. Importantly, areas of the frontoparietal attention network showed increased activation in repetition but not in sequential trials. This dissociation suggests that repeating a display increases attentional control by allowing attention to be reallocated in a second encoding episode. In contrast, sequencing the array poses fewer demands on control, with competition from nonattended objects being reduced by the half-arrays. This idea was corroborated by a third study in which we found optimal VSTM for sequential displays minimizing attentional demands. Importantly these results provide support within the same experimental paradigm for the role of stimulus-driven and top-down attentional control aspects of biased competition theory in setting constraints on VSTM.

Citation

Ihssen, N., Linden, D., Miller, C., & Shapiro, K. (2015). Neural mechanisms underlying visual short-term memory gain for temporally distinct objects. Cerebral Cortex, 25(8), 2149-2159. https://doi.org/10.1093/cercor/bhu021

• Journal Article Type: Article
• Acceptance Date: Feb 18, 2014
• Online Publication Date: Feb 18, 2014
• Publication Date: Aug 1, 2015
• Deposit Date: Feb 11, 2016
• Publicly Available Date: Feb 12, 2016
• Journal: Cerebral Cortex
• Print ISSN: 1047-3211
• Electronic ISSN: 1460-2199
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 25
• Issue: 8
• Pages: 2149-2159
• DOI: https://doi.org/10.1093/cercor/bhu021
• Keywords: Attention, Biased competition, fMRI, Visual short-term memory, Working memory.
• Public URL: https://durham-repository.worktribe.com/output/1388719