Motor system contributions to verbal and non-verbal working memory

Diana A. Liao, Sharif I. Kronemer, Jeffrey M. Yau, John E. Desmond, Cherie L. Marvel

Research output: Contribution to journalArticle

Abstract

Working memory (WM) involves the ability to maintain and manipulate information held in mind. Neuroimaging studies have shown that secondary motor areas activate during WM for verbal content (e.g., words or letters), in the absence of primary motor area activation. This activation pattern may reflect an inner speech mechanism supporting online phonological rehearsal. Here, we examined the causal relationship between motor system activity and WM processing by using transcranial magnetic stimulation (TMS) to manipulate motor system activity during WM rehearsal. We tested WM performance for verbalizable (words and pseudowords) and non-verbalizable (Chinese characters) visual information. We predicted that disruption of motor circuits would specifically affect WM processing of verbalizable information. We found that TMS targeting motor cortex slowed response times (RTs) on verbal WM trials with high (pseudoword) vs. low (real word) phonological load. However, non-verbal WM trials were also significantly slowed with motor TMS. WM performance was unaffected by sham stimulation or TMS over visual cortex (VC). Self-reported use of motor strategy predicted the degree of motor stimulation disruption on WM performance. These results provide evidence of the motor system's contributions to verbal and non-verbal WM processing. We speculate that the motor system supports WM by creating motor traces consistent with the type of information being rehearsed during maintenance.

Original languageEnglish (US)
Article number753
Pages (from-to)1-8
Number of pages8
JournalFrontiers in Human Neuroscience
Volume8
Issue numberSEP
DOIs
StatePublished - Sep 24 2014

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Keywords

  • Motor cortex stimulation
  • Motor system
  • Non-verbal working memory
  • Sternberg memorytask
  • TMS
  • Verbal working memory
  • Visual cortex
  • Working memory

ASJC Scopus subject areas

  • Neuropsychology and Physiological Psychology
  • Neurology
  • Psychiatry and Mental health
  • Biological Psychiatry
  • Behavioral Neuroscience

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