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Updated: May 8, 2026
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MRI-guided dmPFC-rTMS as a Treatment for Treatment-resistant Major Depressive Disorder
Published on: August 11, 2015
Treatment-resistant depression is associated with reduced brain entropy.
Wei-Chen Lin1, Li-Kai Cheng1, Tung-Ping Su2
1Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan; Division of Psychiatry, Faculty of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan; Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei, Taiwan.
Journal of Affective Disorders
|May 7, 2026
Summary
Patients with treatment-resistant depression (TRD) show reduced brain entropy, indicating system-wide hypofunction across major brain networks, cerebellum, and key nuclei. This finding highlights altered brain complexity in TRD.
Area of Science:
- Neuroscience
- Psychiatry
- Medical Imaging
Background:
- Brain entropy quantifies functional complexity, crucial for cognitive and affective processing.
- Systematic examination of brain entropy in treatment-resistant depression (TRD) is lacking.
Purpose of the Study:
- To investigate brain entropy differences between individuals with TRD and healthy controls.
- To identify specific brain regions and networks associated with altered entropy in TRD.
Main Methods:
- Resting-state functional magnetic resonance imaging (fMRI) was performed on 48 adults with TRD and 38 healthy controls.
- Sample entropy, an index of brain entropy, was calculated for 166 regions of interest.
Main Results:
- Patients with TRD exhibited significantly lower entropy in the right angular gyrus, left cerebellar Crus II, and median raphe nucleus (at m=1, r=0.5).
- Broader reductions in resting-state entropy were observed in TRD across multiple regions, including frontal, parietal, cerebellar, and thalamic areas (at r=0.4).
- Affected regions map to large-scale networks (salience, default mode, reward, cerebellar) and involve thalamocortical and serotonergic pathways.
Conclusions:
- TRD is associated with system-wide hypofunction, evidenced by reduced brain entropy.
- This hypofunction spans large-scale brain networks, the cerebellum, and the median raphe nucleus.
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