Related Experiment Video
Updated: Sep 28, 2025
MRI-guided dmPFC-rTMS as a Treatment for Treatment-resistant Major Depressive Disorder
Published on: August 11, 2015
Single session gamma transcranial alternating stimulation does not modulate working memory in depressed patients and
Ulrich Palm1, Carolin Baumgartner2, Lina Hoffmann2
1Department of Psychiatry and Psychotherapy, Hospital of the University of Munich, Munich, Germany; Medical Park Chiemseeblick, Bernau-Felden, Germany.
Objectives:
Gamma transcranial alternating current stimulation (gamma tACS) is considered a non-invasive brain stimulation technique for modulation of cognitive performance and for treatment of psychiatric disorders. There is heterogeneous data on its effectiveness in improving working memory.
Methods:
In this randomized crossover study, we tested 22 patients with major depression and 21 healthy volunteers who received 20 min of active and sham 40 Hz gamma tACS over bilateral dorsolateral prefrontal cortex during a computerized n-back task in a cross-over design.
Results:
We showed no improvement in reaction time and accuracy of working memory during active or sham stimulation in both groups, and no interaction between cognitive load and stimulation conditions.
Conclusion:
The present study suggests that a single session of gamma tACS does not affect cognition in depression. However, the bilateral electrode montage and learning or ceiling effects may have affected results. Overall, this study is in line with the heterogeneous results of previous gamma tACS studies, emphasizing that methodologies and study designs should be harmonized.
