title: Investigations of motor-cortex cortical plasticity following facilitatory and inhibitory transcranial theta-burst stimulation in schizophrenia: a proof-of-concept study.
abstract: Impaired neural plasticity has been proposed as an important pathophysiological feature underlying the neurobiology and symptomatology of schizophrenia. In this proof-of-concept study, we aimed to explore cortical plasticity in schizophrenia patients with two different transcranial theta-burst (TBS) paradigms. TBS induces Ca(2+)-dependent long-term-potentiation (LTP)-like and long-term-depression (LTP)-like plasticity in the human motor cortex. A total of 10 schizophrenia patients and 10 healthy controls were included in this study. Cortical excitability was investigated using transcranial magnetic stimulation in each study participant before and after TBS applied to the left primary motor-cortex on two different days. cTBS600 was used to induce LTD-like and cTBS300 was used to induce LTP-like plasticity in the absence of any prior motor-cortex activation. Repeated measures ANOVAs showed a significant interaction between the timecourse, the study group and the stimulation paradigm (cTBS600 vs. cTBS300) for the left, but not for the right hemisphere. Healthy controls showed an MEP amplitude decrease at a trend level following cTBS600 and a numeric, but not significant, increase in MEP amplitudes following cTBS300. Schizophrenia patients did not show an MEP amplitude decrease following cTBS600, but surprisingly a significant MEP decrease following cTBS300. The proportion of subjects showing the expected changes in motor-cortex excitability following both cTBS paradigms was higher in healthy controls. These preliminary results indicate differences in cortical plasticity following two different cTBS protocols in schizophrenia patients compared to healthy controls. However, the incomplete plasticity response in the healthy controls and the proof-of-concept nature of this study need to be considered as important limitations.
authors.affiliation: Department of Psychiatry and Psychotherapy, Ludwig-Maximilians University, Munich, Germany. Electronic address: Alkomiet.Hasan@med.uni-muenchen.de.
authors.forename: Alkomiet
authors.initials: A
authors.lastname: Hasan
authors.affiliation: Department of Psychiatry and Psychotherapy, University of Goettingen, Goettingen, Germany.
authors.forename: Caroline
authors.initials: C
authors.lastname: Brinkmann
authors.affiliation: Department of Psychiatry and Psychotherapy, Ludwig-Maximilians University, Munich, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Strube
authors.affiliation: Department of Psychiatry and Psychotherapy, Ludwig-Maximilians University, Munich, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Palm
authors.affiliation: Department of Psychiatry and Psychotherapy, Ludwig-Maximilians University, Munich, Germany.
authors.forename: Berend
authors.initials: B
authors.lastname: Malchow
authors.affiliation: Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, UK.
authors.forename: John C
authors.initials: JC
authors.lastname: Rothwell
authors.affiliation: Department of Psychiatry and Psychotherapy, Ludwig-Maximilians University, Munich, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Falkai
authors.affiliation: Department of Psychiatry and Psychotherapy, University of Goettingen, Goettingen, Germany; Centre of Mental Health, Darmstadt-Dieburg Clinics, Darmstadt, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Wobrock
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D016022:Case-Control Studies; D019054:Evoked Potentials, Motor; D005260:Female; D006801:Humans; D017774:Long-Term Potentiation; D036881:Long-Term Synaptic Depression; D008297:Male; D009044:Motor Cortex / Q000503:physiopathology*; D009473:Neuronal Plasticity; D012559:Schizophrenia / Q000503:physiopathology*; D050781:Transcranial Magnetic Stimulation / Q000379:methods*; D055815:Young Adult
keywords: Calcium signaling; Cortical excitability; Neural plasticity; Schizophrenia; Theta-burst stimulation