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Updated: Aug 15, 2026

Design and Implementation of an fMRI Study Examining Thought Suppression in Young Women with, and At-risk, for Depression
Published on: May 19, 2015
Evidence for impaired cortical inhibition in patients with unipolar major depression
Malek Bajbouj1, Sarah H Lisanby, Undine E Lang
1Department of Psychiatry, Charité University Medicine Berlin, Berlin, Germany. malek.bajbouj@charite.de
Background:
Several lines of evidence suggest that central cortical inhibitory mechanisms, especially associated with gamma-aminobutyric acid (GABA) neurotransmission, may play a role in the pathophysiology of major depression. Transcranial magnetic stimulation is a useful tool for investigating central cortical inhibitory mechanisms associated with GABAergic neurotransmission in psychiatric and neurological disorders.
Methods:
By means of transcranial magnetic stimulation, different parameters of cortical excitability, including motor threshold, the cortical silent period, and intracortical inhibition/facilitation, were investigated in 20 medication-free depressed patients and 20 age- and gender-matched healthy volunteers.
Results:
Silent period and intracortical inhibition were reduced in depressed patients, consistent with a reduced GABAergic tone. Moreover, patients showed a significant hemispheric asymmetry in motor threshold.
Conclusions:
This study provides evidence of reduced GABAergic tone and motor threshold asymmetry in patients with major depression.
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