Cortical Excitability and Inhibition in MDD
Condition: Major Depressive Disorder, Recurrent, Mild; Depressive Disorder, Major
MeSH terms: Depressive Disorder; Depression; Depressive Disorder, Major
Study type: Observational

Summary: 
      The purpose of this study is to learn if measures of brain activity are different in children
      and adolescents with depression who are in different stages of treatment. This is important
      because it may identify a biological marker for depression that could one day be used to
      identify depressed children who would benefit from certain treatments (medications for
      example), or to monitor how well treatments are working. Brain activity measures(known as
      cortical excitability and inhibition) will be collected by Transcranial Magnetic Stimulation
      (TMS). TMS is a noninvasive (no surgery or implants) brain stimulation technology which can
      make parts of the brain work without putting any wires or chemicals into the body.
      Measurements will take place over one 3-hour visit. This study does not provide any form of
      treatment.

      *There is an optional portion of the study that uses a brain scan to gather measures of brain
      structure and brain chemicals. The brain scan is called magnetic resonance and spectroscopy
      (MRI/MRS). MRI/MRS uses magnetic fields to study the structure of the brain and brain
      chemicals. The PI will determine eligibility for the MRI/MRS portion of the study.
    

Detailed description: 
      This study is focused on understanding the neurophysiology of major depressive disorder
      (MDD), and the impact of selective serotonin reuptake inhibitors (SSRIs) in children and
      adolescents. This is a cross-sectional study which will utilize single and paired-pulse
      transcranial magnetic stimulation (TMS) to collect measures of glutamatergic cortical
      excitability (the motor threshold and intracortical facilitation), and GABAergic cortical
      inhibition (the cortical silent period and intracortical inhibition) of the motor cortex in
      chilren and adolescents in various disease states of MDD. The optional proton magnetic
      resonance spectroscopy and imaging scans (MRS/MRI) at 3 Tesla (3T) will examine glutamate
      concentrations in the motor cortex and anterior cingulate cortex.

      This is a biomarker study (MRI/MRS and TMS neurophysiology measures); treatment is not
      provided in any form. This study will not utilize Repetitive Transcranial Magnetic
      Stimulation (rTMS).
    

Intervention name(s): Transcranial Magnetic Stimulation (TMS); Magnetic Resonance Spectroscopy and Imaging
Intervention type(s): Device; Device
Intervention description(s): Single and paired-pulse TMS applied to the motor cortex will collect measures of cortical excitability and inhibition.; MRS/MRI Scans will examine glutamate concentrations in the motor cortex and anterior cingulate cortex.
Other intervention name(s): Device: Magstim Model 200; MRS/MRI
Observational model: Case-Control
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        This protocol will plan to screen depressed children and adolescents who are seeking
        treatment at Mayo Clinic in Rochester, MN, using strict inclusion and exclusion criteria.
        These adolescents will represent gender and minority distribution consistent with the
        Rochester metro/rural area demographic distribution. This study will be inclusive of all
        races, genders, and socioeconomic classes.
      
Keywords: TMS; Adolescent; Child; MDD; Major depressive disorder; Mild MDD; Mild depression; SSRI; Motor cortex; Cortical excitability; Cortical inhibition; Cortical silent period; Motor threshold; Intracortical facilitation; Intracortical inhibition; gamma-aminobutyric acid (GABA); Glutamate; N-methyl-D-aspartate (NMDA); Magnetic resonance spectroscopy; MRS