Abstract Details

Title Distinctive Pattern of Cortical Excitability in Vascular Depression and Major Depression

Topic Clinical Neurophysiology

Presentation(s) P07 - (-)

Poster/Presentation
Number 184

Objective

Background BACKGROUND: Changes in Transcranial Magnetic Stimulation-related parameters of cortical excitability have been associated with MD. Conversely, although the clinical and neuroradiological profile of VD has been well depicted, neurophysiological studies providing direction of causation between the white matter lesions and the late onset depression are scarce.

Design/Methods DESIGN/METHODS: Patients with recurrent MD (n=11), VD (n=11) and healthy controls (n=11) underwent a bilateral study of resting motor threshold (rMT), cortical silent period, intracortical inhibition and facilitation (ICF) at interstimulus intervals (ISI) of 1, 3, 5, 7, 10 and 15 ms. All the MD patients were receiving antidepressant medication at the time of the study.

Results RESULTS: The Wilcoxon test used for the comparison between left and right hemisphere of patients and controls showed a statistically significant increase of rMT in the left hemisphere compared to the right in MD patients. An enhancement of ICF at ISI of 15 ms was observed in the right hemisphere of VD patients. No other differences among the groups and between the two hemispheres were found.

Conclusions CONCLUSIONS: Our study provides a neurophysiological explanation for the different neurobiological and neurochemical processes underlying VD and MD. The enhanced ICF observed in VD patients might be probably related to a glutamate-dependent compensatory plasticity in response to vascular damage of the frontal cortical-subcortical loops implicated in mood regulation and cognition. The asymmetry in cortical excitability, as indexed by the rMT, in MD patients is consistent with a global imbalance of both excitatory and inhibitory circuits.On the contrary, neither significant intercortical asymmetry nor involvement of the inhibitory GABAergic intracortical circuits were found in VD patients. Taken together, these findings support the "vascular depression hypothesis" as a different syndrome with respect to MD.

Authors/Disclosures
Giovanni Pennisi, MD PRESENTER	No disclosure on file
	No disclosure on file
	No disclosure on file
	No disclosure on file
Giuseppe Lanza, MD	No disclosure on file
	No disclosure on file
	No disclosure on file
Ralph L. Sacco, MD, MS, FAHA	Dr. Sacco has received personal compensation in the range of $100,000-$499,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for American Heart Association. The institution of Dr. Sacco has received research support from NIH, NINDS, NCATS, NIMHD. The institution of Dr. Sacco has received research support from FL Department of Health. Dr. Sacco has received research support from University of Washington, Seattle. Dr. Sacco has received publishing royalties from a publication relating to health care.
Rita Bella	No disclosure on file
	No disclosure on file

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