title: Working memory capacity differentially influences responses to tDCS and HD-tDCS in a retro-cue task.
abstract: There is growing interest in non-invasive brain stimulation techniques. A drawback is that the relationship between stimulation and cognitive outcomes for various tasks are unknown. Transcranial direct current stimulation (tDCS) provides diffuse current spread, whereas high-definition tDCS (HD-tDCS) provides more targeted current. The direction of behavioral effects after tDCS can be difficult to predict in cognitive realms such as attention and working memory (WM). Previously, we showed that in low and high WM capacity groups tDCS modulates performance in nearly equal and opposite directions on a change detection task, with improvement for the high capacity participants alone. Here, we used the retro-cue paradigm to test attentional shifting among items in WM to investigate whether WM capacity (WMC) predicted different behavioral consequences during anodal tDCS or HD-tDCS to posterior parietal cortex (PPC). In two experiments, with 24 participants each, we used different stimulus categories (colored circles, letters) and stimulation sites (right, left PPC). The results showed a significant (Experiment 1) or trending (Experiment 2) WMC x stimulation interaction. Compared to tDCS, after HD-tDCS the retro-cueing benefit was significantly greater for the low WMC group but numerically worse for the high WMC group. These data highlight the importance of considering group differences when using non-invasive neurostimulation techniques.
authors.affiliation: University of Nevada, Reno, Department of Psychology, Program in Cognitive and Brain Sciences, Reno, NV 89557, United States; Yaşar University, Department of Psychology, İzmir, Turkey.
authors.forename: Filiz
authors.initials: F
authors.lastname: Gözenman
authors.affiliation: University of Nevada, Reno, Department of Psychology, Program in Cognitive and Brain Sciences, Reno, NV 89557, United States. Electronic address: mberryhill@unr.edu.
authors.forename: Marian E
authors.initials: ME
authors.lastname: Berryhill
mesh_terms: D001288:Attention / Q000502:physiology*; D003463:Cues; D006801:Humans; D008570:Memory, Short-Term / Q000502:physiology*; D009483:Neuropsychological Tests; D010296:Parietal Lobe / Q000502:physiology*; D015203:Reproducibility of Results; D065908:Transcranial Direct Current Stimulation / Q000379:methods*
keywords: Group differences; HD-tDCS; Working memory; Working memory capacity; tDCS