Mapping entrained brain oscillations during transcranial alternating current stimulation (tACS).
Transcranial alternating current stimulation (tACS), a non-invasive and well-tolerated form of electric brain stimulation, can influence perception, memory, as well as motor and cognitive function. While the exact underlying neurophysiological mechanisms are unknown, the effects of tACS are mainly attributed to frequency-specific entrainment of endogenous brain oscillations in brain areas close to the stimulation electrodes, and modulation of spike timing dependent plasticity reflected in gamma band oscillatory responses. tACS-related electromagnetic stimulator artifacts, however, impede investigation of these neurophysiological mechanisms. Here we introduce a novel approach combining amplitude-modulated tACS during whole-head magnetoencephalography (MEG) allowing for artifact-free source reconstruction and precise mapping of entrained brain oscillations underneath the stimulator electrodes. Using this approach, we show that reliable reconstruction of neuromagnetic low- and high-frequency oscillations including high gamma band activity in stimulated cortical areas is feasible opening a new window to unveil the mechanisms underlying the effects of stimulation protocols that entrain brain oscillatory activity.
Applied Neurotechnology Lab, Department of Psychiatry and Psychotherapy, University Hospital of Tübingen, Germany.
Matthias
M
Witkowski
Applied Neurotechnology Lab, Department of Psychiatry and Psychotherapy, University Hospital of Tübingen, Germany; Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany; Donders Centre for Brain, Cognition and Behavior, Department of Artificial Intelligence, Radboud University Nijmegen, Nijmegen, The Netherlands.
Eliana
E
Garcia-Cossio
Applied Neurotechnology Lab, Department of Psychiatry and Psychotherapy, University Hospital of Tübingen, Germany.
Bankim S
BS
Chander
MEG Center, University of Tübingen, Tübingen, Germany; CIMeC, Center for Mind/Brain Sciences, University of Trento, Trento, Italy.
Christoph
C
Braun
Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.
Niels
N
Birbaumer
National Institute of Mental Health (NIMH), MEG Core Facility, Bethesda, USA.
Stephen E
SE
Robinson
Applied Neurotechnology Lab, Department of Psychiatry and Psychotherapy, University Hospital of Tübingen, Germany; Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany. Electronic address: surjo.soekadar@uni-tuebingen.de.
Surjo R
SR
Soekadar
D000465:Algorithms; D001683:Biological Clocks / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D058256:Brain Waves / Q000502:physiology*; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D065908:Transcranial Direct Current Stimulation / Q000379:methods*; D055815:Young Adult
Entrainment; Neuromagnetic brain oscillations; Transcranial alternating current stimulation; Whole-head magnetoencephalography