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Updated: Jan 17, 2026
Combined Transcranial Magnetic Stimulation and Electroencephalography of the Dorsolateral Prefrontal Cortex
Published on: August 17, 2018
Decreased long-interval intracortical inhibition in the dorsolateral prefrontal cortex using TMS-EEG in patients with
Mayuko Takano1, Masataka Wada2, Shinichiro Nakajima3
1Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan; Teijin Pharma Limited, Tokyo, Japan.
Background:
GABA(B) receptor-mediated inhibitory dysfunction is implicated in the pathophysiology of treatment-resistant depression (TRD); however, the underlying mechanisms remain unclear. Long-interval intracortical inhibition (LICI) paradigm using transcranial magnetic stimulation combined with electroencephalography (TMS-EEG) enables the evaluation of GABA(B) receptor-mediated cortical inhibition from the cortex.
Objective:
We aimed to evaluate the LICI effect in the left dorsolateral prefrontal cortex (DLPFC) of TRD using combined TMS-EEG.
Methods:
Thirty individuals with TRD and age- and sex-matched healthy controls (HC) underwent the LICI TMS-EEG, which consisted of single- and paired-pulse TMS in the left DLPFC, with an interstimulus interval of 100 ms. The LICI effects were evaluated by comparing time-series and time-frequency signals at the sensor and source levels within- and between-groups (TRD vs. HC).
Results:
Within-group comparisons showed inhibitory changes at the signal source level for the HC group in the time-series analysis, and inhibitory changes at the sensor and signal source levels for both groups in the time-frequency analysis. Between-group comparisons showed a significant reduction of the LICI effect in the time-series signal (35-87 ms) and θ-β band power at the source level in TRD compared to HC.
Conclusion:
Our findings suggest that reduced LICI in the DLPFC may contribute to the pathophysiological basis of TRD.
