Dataset Information

Developmental aspects of cortical excitability and inhibition in depressed and healthy youth: an exploratory study.

ABSTRACT:

Objectives

The objective of this post-hoc exploratory analysis was to examine the relationship between age and measures of cortical excitability and inhibition.

Methods

Forty-six participants (24 with major depressive disorder and 22 healthy controls) completed MT, SICI, ICF, and CSP testing in a cross-sectional protocol. Of these 46 participants, 33 completed LICI testing. Multiple linear robust regression and Spearman partial correlation coefficient were used to examine the relationship between age and the TMS measures.

Results

In the overall sample of 46 participants, age had a significant negative relationship with motor threshold (MT) in both the right (r s = -0.49, adjusted p = 0.007; β = -0.08, adjusted p = 0.001) and left (r s = -0.42, adjusted p = 0.029; β = -0.05, adjusted p = 0.004) hemispheres. This significant negative relationship of age with MT was also observed in the sample of depressed youth in both the right (r s = -0.70, adjusted p = 0.002; β = -0.09, adjusted p = 0.001) and left (r s = -0.54, adjusted p = 0.034; β = -0.05, adjusted p = 0.017) hemispheres, but not in healthy controls. In the sample of the 33 participants who completed LICI testing, age had a significant negative relationship with LICI (200 ms interval) in both the right (r s = -0.48, adjusted p = 0.05; β = -0.24, adjusted p = 0.007) and left (r s = -0.64, adjusted p = 0.002; β = -0.23, adjusted p = 0.001) hemispheres. This negative relationship between age and LICI (200 ms interval) was also observed in depressed youth in both the right (r s = -0.76, adjusted p = 0.034; β = -0.35, adjusted p = 0.004) and left (r s = -0.92, adjusted p = 0.002; β = -0.25, adjusted p = 0.001) hemispheres.

Conclusion

These findings suggest that younger children have higher MTs. This is more pronounced in depressed youth than healthy controls. LICI inhibition may also increase with age in youth.

SUBMITTER: Croarkin PE

PROVIDER: S-EPMC4151107 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

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Publications

Developmental aspects of cortical excitability and inhibition in depressed and healthy youth: an exploratory study.

Croarkin Paul E PE Nakonezny Paul A PA Lewis Charles P CP Zaccariello Michael J MJ Huxsahl John E JE Husain Mustafa M MM Kennard Betsy D BD Emslie Graham J GJ Daskalakis Zafiris J ZJ

Frontiers in human neuroscience 20140902

<h4>Objectives</h4>The objective of this post-hoc exploratory analysis was to examine the relationship between age and measures of cortical excitability and inhibition.<h4>Methods</h4>Forty-six participants (24 with major depressive disorder and 22 healthy controls) completed MT, SICI, ICF, and CSP testing in a cross-sectional protocol. Of these 46 participants, 33 completed LICI testing. Multiple linear robust regression and Spearman partial correlation coefficient were used to examine the rela ...[more]

PMID: 25228870

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Project description:Introduction: Transcranial magnetic stimulation (TMS) research has suggested dysfunction in cortical glutamatergic systems in adolescent depression, while proton magnetic resonance spectroscopy (1H-MRS) studies have demonstrated deficits in concentrations of glutamatergic metabolites in depressed individuals in several cortical regions, including the anterior cingulate cortex (ACC). However, few studies have combined TMS and MRS methods to examine relationships between glutamatergic neurochemistry and excitatory and inhibitory neural functions, and none have utilized TMS-MRS methodology in clinical populations or in youth. This exploratory study aimed to examine relationships between TMS measures of cortical excitability and inhibition and concentrations of glutamatergic metabolites as measured by 1H-MRS in depressed adolescents. Methods: Twenty-four adolescents (aged 11-18 years) with depressive symptoms underwent TMS testing, which included measures of the resting motor threshold (RMT), cortical silent period (CSP), short-interval intracortical inhibition (SICI), and intracortical facilitation (ICF). Fourteen participants from the same sample also completed 1H-MRS in a 3 T MRI scanner after TMS testing. Glutamate + glutamine (Glx) concentrations were measured in medial ACC and left primary motor cortex voxels with a TE-optimized PRESS sequence. Metabolite concentrations were corrected for cerebrospinal fluid (CSF) after tissue segmentation. Pearson product-moment and Spearman rank-order correlations were calculated to assess relationships between TMS measures and [Glx]. Results: In the left primary motor cortex voxel, [Glx] had a significant positive correlation with the RMT. In the medial ACC voxel, [Glx] had significant positive correlations with ICF at the 10-ms and 20-ms interstimulus intervals (ISIs). Conclusion: These preliminary data implicate glutamate in cortical excitatory processes measured by TMS. Limitations included small sample size, lack of healthy control comparators, possible age- and sex-related effects, and observational nature of the study. Further research aimed at examining the relationship between glutamatergic metabolite concentrations measured through MRS and the excitatory and inhibitory physiology measured through TMS is warranted. Combined TMS-MRS methods show promise for future investigations of the pathophysiology of depression in adults as well as in children and adolescents.

Dataset Information

Developmental aspects of cortical excitability and inhibition in depressed and healthy youth: an exploratory study.

Objectives

Methods

Results

Conclusion

Publications

Developmental aspects of cortical excitability and inhibition in depressed and healthy youth: an exploratory study.

Similar Datasets

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