The speed of parietal theta frequency drives visuospatial working memory capacity
نویسندگان
چکیده
The speed of theta brain oscillatory activity is thought to play a key role in determining working memory (WM) capacity. Individual differences in the length of a theta cycle (ranging between 4 and 7 Hz) might determine how many gamma cycles (>30 Hz) can be nested into a theta wave. Gamma cycles are thought to represent single memory items; therefore, this interplay could determine individual memory capacity. We directly tested this hypothesis by means of parietal transcranial alternating current stimulation (tACS) set at slower (4 Hz) and faster (7 Hz) theta frequencies during a visuospatial WM paradigm. Accordingly, we found that 4-Hz tACS enhanced WM capacity, while 7-Hz tACS reduced WM capacity. Notably, these effects were found only for items presented to the hemifield contralateral to the stimulation site. This provides causal evidence for a frequency-dependent and spatially specific organization of WM storage, supporting the theta-gamma phase coupling theory of WM capacity.
منابع مشابه
Enhancement of Visuospatial Working Memory by Transcranial Direct Current Stimulation (tDCS) on Prefrontal and Parietal Cortices
Objective: Previous studies have reported dorsolateral prefrontal cortex (DLPFC) and posterior parietal (PPC) activation during the performance of spatial working memory (SWM), so we decided to investigate the comparison of Transcranial Direct current stimulation (tDCS) effect between these two areas. Methods: Fifty-four healthy right-handed students (27 female, 27 male; age= 24.3±.2 years) w...
متن کاملThe effect of verbal and visuospatial working memory spans on collocation processing in learners of English
Much interest has recently been directed toward the knowledge of collocations in the field of second language learning since they have been asserted to improve fluency. The current study was intended to examine the effect of verbal and visuospatial working memory spans on the processing of collocations using a Self-Pace Reading Task (SPRT) and relevant working memory tasks. To this end, partici...
متن کاملPeak Frequency in the Theta and Alpha Bands Correlates with Human Working Memory Capacity
Theta oscillations in the local field potential of neural ensembles are considered key mediators of human working memory. Theoretical accounts arising from animal hippocampal recordings propose that the phase of theta oscillations serves to instantiate sequential neuronal firing to form discrete representations of items held online. Human evidence of phase relationships in visual working memory...
متن کاملFrequency-Unspecific Effects of θ-tACS Related to a Visuospatial Working Memory Task
Working memory (WM) is crucial for intelligent cognitive functioning, and synchronization phenomena in the fronto-parietal network have been suggested as an underlying neural mechanism. In an attempt to provide causal evidence for this assumption, we applied transcranial alternating current stimulation (tACS) at theta frequency over fronto-parietal sites during a visuospatial match-to-sample (M...
متن کاملThe Effects of Theta and Gamma tACS on Working Memory and Electrophysiology
A single blind sham-controlled study was conducted to explore the effects of theta and gamma transcranial alternating current stimulation (tACS) on offline performance on working memory tasks. In order to systematically investigate how specific parameters of tACS affect working memory, we manipulated the frequency of stimulation (theta frequency vs. gamma frequency), the type of task (n-back vs...
متن کامل