Neural Mechanisms Underlying Visual Short-Term Memory Gain for Temporally Distinct Objects

Research output: Contribution to journalArticle

Authors

  • Niklas Ihssen
  • David E. J. Linden
  • Claire E. Miller
  • Kim Shapiro

Colleges, School and Institutes

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 se- quencing and repeating displays increased brain activation in extra- striate 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 acti- vation 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.

Details

Original languageEnglish
Pages (from-to)2149-2159
Number of pages11
JournalCerebral Cortex
Volume25
Early online date18 Feb 2014
Publication statusPublished - 2015