Transcranial direct current stimulation of the prefrontal cortex modulates working memory performance: combined behavioural and electrophysiological evidence
- Equal contributors
1 Department of Neurology, Otto v. Guericke University Magdeburg, Germany
2 German Centre for Neurodegenerative Diseases (DZNE) Magdeburg, Germany
3 Department of Psychology, Neuropsychology Lab, Carl von Ossietzky University of Oldenburg, Germany
4 Institute of Psychology, Division of Neuropsychology, University of Zurich, Switzerland
5 Department of Experimental Psychology, Carl von Ossietzky University Oldenburg, Germany
BMC Neuroscience 2011, 12:2 doi:10.1186/1471-2202-12-2Published: 6 January 2011
Transcranial direct current stimulation (tDCS) is a technique that can systematically modify behaviour by inducing changes in the underlying brain function. In order to better understand the neuromodulatory effect of tDCS, the present study examined the impact of tDCS on performance in a working memory (WM) task and its underlying neural activity. In two experimental sessions, participants performed a letter two-back WM task after sham and either anodal or cathodal tDCS over the left dorsolateral prefrontal cortex (DLPFC).
Results showed that tDCS modulated WM performance by altering the underlying oscillatory brain activity in a polarity-specific way. We observed an increase in WM performance and amplified oscillatory power in the theta and alpha bands after anodal tDCS whereas cathodal tDCS interfered with WM performance and decreased oscillatory power in the theta and alpha bands under posterior electrode sides.
The present study demonstrates that tDCS can alter WM performance by modulating the underlying neural oscillations. This result can be considered an important step towards a better understanding of the mechanisms involved in tDCS-induced modulations of WM performance, which is of particular importance, given the proposal to use electrical brain stimulation for the therapeutic treatment of memory deficits in clinical settings.