Altered interhemispheric signal propagation in schizophrenia and depression

Jeanette Hui; Reza Zomorrodi; Pantelis Lioumis; Elnaz Ensafi; Daphne Voineskos; Aristotle Voineskos; Itay Hadas; Tarek K Rajji; Daniel M Blumberger; Zafiris J Daskalakis

doi:10.1016/j.clinph.2021.03.039

Altered interhemispheric signal propagation in schizophrenia and depression

Clin Neurophysiol. 2021 Jul;132(7):1604-1611. doi: 10.1016/j.clinph.2021.03.039. Epub 2021 Apr 26.

Authors

Affiliations

¹ Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, ON M6J 1H4, Canada; Department of Medicine, University of Toronto, Toronto, Ontario M5S 1A1, Canada.
² Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, ON M6J 1H4, Canada.
³ Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, ON M6J 1H4, Canada; Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo FI-00076, Finland.
⁴ Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, ON M6J 1H4, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario M5S 1A1, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario M5S 1A1, Canada.
⁵ Institute of Medical Science, University of Toronto, Toronto, Ontario M5S 1A1, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario M5S 1A1, Canada; Campbell Family Mental Health Institute, Centre for Addiction and Mental Health, Toronto M5T 1R8, Canada.
⁶ Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, ON M6J 1H4, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario M5S 1A1, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario M5S 1A1, Canada. Electronic address: zdaskalakis@health.ucsd.edu.

PMID: 34030057
DOI: 10.1016/j.clinph.2021.03.039

Abstract

Objective: Altered interhemispheric connectivity is implicated in the pathophysiology of schizophrenia (SCZ) and major depressive disorder (MDD) and may account for deficits in lateralized cognitive processes. We measured transcranial magnetic stimulation evoked interhemispheric signal propagation (ISP), a non-invasive measure of transcallosal connectivity, and hypothesized that the SCZ and MDD groups will have increased ISP compared to healthy controls.

Methods: We evaluated ISP over the dorsolateral prefrontal cortex in 34 patients with SCZ and 34 patients with MDD compared to 32 age and sex-matched healthy controls.

Results: ISP was significantly increased in patients with SCZ and patients with MDD compared to healthy controls but did not differ between patient groups. There were no effects of antidepressant, antipsychotic, and benzodiazepine medications on ISP and our results remained unchanged after re-analysis with a region of interest method.

Conclusion: Altered ISP was found in both SCZ and MDD patient groups. This indicates that disruptions of interhemispheric signaling processes can be indexed with ISP across psychiatric populations.

Significance: These findings enhance our knowledge of the physiological mechanisms of interhemispheric imbalances in SCZ and MDD, which may serve as potential treatment targets in future patients.

Keywords: Depression; Electroencephalography; Prefrontal cortex; Schizophrenia; Transcranial magnetic stimulation.

MeSH terms

Adult
Depressive Disorder, Major / diagnosis*
Depressive Disorder, Major / physiopathology*
Electroencephalography / methods
Female
Humans
Male
Prefrontal Cortex / physiopathology*
Schizophrenia / diagnosis*
Schizophrenia / physiopathology*
Transcranial Magnetic Stimulation / methods*