title: Different patterns of cortical excitability in major depression and vascular depression: a transcranial magnetic stimulation study.
abstract: BACKGROUND
  Clinical and functional studies consider major depression (MD) and vascular depression (VD) as different neurobiological processes. Hypoexcitability of the left frontal cortex to transcranial magnetic stimulation (TMS) is frequently reported in MD, whereas little is known about the effects of TMS in VD. Thus, we aimed to assess and compare motor cortex excitability in patients with VD and MD.
  
  
  METHODS
  Eleven VD patients, 11 recurrent drug-resistant MD patients, and 11 healthy controls underwent clinical, neuropsychological and neuroimaging evaluations in addition to bilateral resting motor threshold, cortical silent period, and paired-pulse TMS curves of intracortical excitability. All patients continued on psychotropic drugs, which were unchanged throughout the study.
  
  
  RESULTS
  Scores on one of the tests evaluating frontal lobe abilities (Stroop Color-Word interference test) were worse in patients compared with controls. The resting motor threshold in patients with MD was significantly higher in the left hemisphere compared with the right (p < 0.05), and compared with the VD patients and controls. The cortical silent period was bilaterally prolonged in MD patients compared with VD patients and controls, with a statistically significant difference in the left hemisphere (p < 0.01). No differences were observed in the paired-pulse curves between patients and controls.
  
  
  CONCLUSIONS
  This study showed distinctive patterns of motor cortex excitability between late-onset depression with subcortical vascular disease and early-onset recurrent drug resistant MD. The data provide a TMS model of the different processes underlying VD and MD. Additionally, our results support the "Vascular depression hypothesis" at the neurophysiological level, and confirm the inter-hemispheric asymmetry to TMS in patients with MD. We were unable to support previous findings of impaired intracortical inhibitory mechanisms to TMS in patients with MD, although a drug-induced effect on our results cannot be excluded. This study may aid the understanding of the pathogenetic differences underlying the clinical spectrum of depressive disorders.
authors.forename: Carmen
authors.initials: C
authors.lastname: Concerto
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Lanza
authors.forename: Mariagiovanna
authors.initials: M
authors.lastname: Cantone
authors.forename: Manuela
authors.initials: M
authors.lastname: Pennisi
authors.forename: Daniela
authors.initials: D
authors.lastname: Giordano
authors.forename: Concetto
authors.initials: C
authors.lastname: Spampinato
authors.forename: Riccardo
authors.initials: R
authors.lastname: Ricceri
authors.affiliation: Department "G,F, Ingrassia", Section of Neurosciences, University of Catania, Via Santa Sofia, 78-95123 Catania, Italy. pennigi@unict.it.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Pennisi
authors.forename: Eugenio
authors.initials: E
authors.lastname: Aguglia
authors.forename: Rita
authors.initials: R
authors.lastname: Bella
mesh_terms: D000368:Aged; D003866:Depressive Disorder / Q000503:physiopathology* / Q000523:psychology; D003865:Major Depressive Disorder / Q000503:physiopathology* / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology*; D009483:Neuropsychological Tests; D050781:Transcranial Magnetic Stimulation