title: Language and Memory Improvements following tDCS of Left Lateral Prefrontal Cortex.
abstract: Recent research demonstrates that performance on executive-control measures can be enhanced through brain stimulation of lateral prefrontal regions. Separate psycholinguistic work emphasizes the importance of left lateral prefrontal cortex executive-control resources during sentence processing, especially when readers must override early, incorrect interpretations when faced with temporary ambiguity. Using transcranial direct current stimulation, we tested whether stimulation of left lateral prefrontal cortex had discriminate effects on language and memory conditions that rely on executive-control (versus cases with minimal executive-control demands, even in the face of task difficulty). Participants were randomly assigned to receive Anodal, Cathodal, or Sham stimulation of left lateral prefrontal cortex while they (1) processed ambiguous and unambiguous sentences in a word-by-word self-paced reading task and (2) performed an n-back memory task that, on some trials, contained interference lure items reputed to require executive-control. Across both tasks, we parametrically manipulated executive-control demands and task difficulty. Our results revealed that the Anodal group outperformed the remaining groups on (1) the sentence processing conditions requiring executive-control, and (2) only the most complex n-back conditions, regardless of executive-control demands. Together, these findings add to the mounting evidence for the selective causal role of left lateral prefrontal cortex for executive-control tasks in the language domain. Moreover, we provide the first evidence suggesting that brain stimulation is a promising method to mitigate processing demands encountered during online sentence processing.
authors.affiliation: Department of Psychology, University of Illinois at Urbana-Champaign, Champaign, Illinois, United States of America; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America.
authors.forename: Erika K
authors.initials: EK
authors.lastname: Hussey
authors.affiliation: Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America.
authors.forename: Nathan
authors.initials: N
authors.lastname: Ward
authors.affiliation: Department of Education Psychology, University of Illinois at Urbana-Champaign, Champaign, Illinois, United States of America; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America.
authors.forename: Kiel
authors.initials: K
authors.lastname: Christianson
authors.affiliation: Department of Psychology, University of Illinois at Urbana-Champaign, Champaign, Illinois, United States of America; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America.
authors.forename: Arthur F
authors.initials: AF
authors.lastname: Kramer
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D007802:Language; D008297:Male; D008568:Memory; D017397:Prefrontal Cortex; D065908:Transcranial Direct Current Stimulation