title: Cortical excitability of psychiatric disorders: reduced post-exercise facilitation in depression compared to schizophrenia and controls.
abstract: OBJECTIVE
  In normal subjects, motor evoked potentials (MEPs) produced by transcranial magnetic stimulation (TMS) from the motor cortex are increased after non-fatiguing exercise of hand muscles. This phenomenon is called post-exercise facilitation. This study aims to test the hypothesis that psychiatric syndromes (major depressive episode, schizophrenia) have different levels of post-exercise facilitation compared to controls.
  
  
  METHODS
  Patients with DSM-IV major depressive episode (six female, four male), schizophrenia (two female, nine male) and a control group (nine female, four male) participated. MEPs were elicited pre- and post-exercise from the contralateral abductor pollicis brevis by TMS over the primary motor cortex.
  
  
  RESULTS
  Post-exercise facilitation expressed as a percentage of baseline was 510% in controls, 110% in depression and 190% in schizophrenia. There were significant differences in patients with depression and schizophrenia compared to controls (p = 0.0001, p = 0.0008).
  
  
  CONCLUSIONS
  Post-exercise facilitation was reduced in depression and schizophrenia, suggesting impaired cortical excitability in these disorders. Further studies may discriminate between the two groups.
authors.affiliation: Department of Psychological Medidine, Royal Hobart Hospital, Liverpool Street, Hobart, Tasmania 7000, Australia. philip.reid@dhhs.tas.gov.au
authors.forename: Philip D
authors.initials: PD
authors.lastname: Reid
authors.forename: Brett
authors.initials: B
authors.lastname: Daniels
authors.forename: Marzena
authors.initials: M
authors.lastname: Rybak
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Turnier-Shea
authors.forename: Saxby
authors.initials: S
authors.lastname: Pridmore
mesh_terms: D000328:Adult; D001143:Arousal / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D003865:Major Depressive Disorder / Q000175:diagnosis; D019054:Evoked Potentials, Motor / Q000502:physiology*; D015444:Exercise; D005260:Female; D006801:Humans; D015225:Magnetoencephalography / Q000295:instrumentation; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D012559:Schizophrenia / Q000175:diagnosis