Electrical brain stimulation improves cognitive performance by modulating functional connectivity and task-specific activation.
Excitatory anodal transcranial direct current stimulation (atDCS) can improve human cognitive functions, but neural underpinnings of its mode of action remain elusive. In a cross-over placebo ("sham") controlled study we used functional magnetic resonance imaging (fMRI) to investigate neurofunctional correlates of improved language functions induced by atDCS over a core language area, the left inferior frontal gyrus (IFG). Intrascanner transcranial direct current stimulation-induced changes in overt semantic word generation assessed behavioral modulation; task-related and task-independent (resting-state) fMRI characterized language network changes. Improved word-retrieval during atDCS was paralleled by selectively reduced task-related activation in the left ventral IFG, an area specifically implicated in semantic retrieval processes. Under atDCS, resting-state fMRI revealed increased connectivity of the left IFG and additional major hubs overlapping with the language network. In conclusion, atDCS modulates endogenous low-frequency oscillations in a distributed set of functionally connected brain areas, possibly inducing more efficient processing in critical task-relevant areas and improved behavioral performance.
Department of Neurology, Center for Stroke Research Berlin, and Cluster of Excellence NeuroCure, Charite Universitätsmedizin, Berlin 10117, Germany. marcus.meinzer@charite.de
Marcus
M
Meinzer
Daria
D
Antonenko
Robert
R
Lindenberg
Stefan
S
Hetzer
Lena
L
Ulm
Keren
K
Avirame
Tobias
T
Flaisch
Agnes
A
Flöel
D000328:Adult; D001921:Brain / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D046690:Deep Brain Stimulation / Q000379:methods*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009415:Nerve Net / Q000502:physiology*; D010865:Pilot Projects; D011597:Psychomotor Performance / Q000502:physiology*; D055815:Young Adult