title: Brain State-Dependent Transcranial Magnetic Closed-Loop Stimulation Controlled by Sensorimotor Desynchronization Induces Robust Increase of Corticospinal Excitability.
abstract: Desynchronization of sensorimotor rhythmic activity increases instantaneous corticospinal excitability, as indexed by amplitudes of motor-evoked potentials (MEP) elicited by transcranial magnetic stimulation (TMS). The accumulative effect of cortical stimulation in conjunction with sensorimotor desynchronization is, however, unclear.
  
  
  
  The aim of this study was to investigate the effects of repetitive pairing event-related desynchronization (ERD) with TMS of the precentral gyrus on corticospinal excitability.
  
  
  
  Closed-loop single-pulse TMS was controlled by beta-band (16-22 Hz) ERD during motor-imagery of finger extension and applied within a brain-computer interface environment in eleven healthy subjects. The same number and pattern of stimuli were applied in a control group of eleven subjects during rest, i.e. independent of ERD. To probe for plasticity resistant to depotentiation, stimulation protocols were followed by a depotentiation task.
  
  
  
  Brain state-dependent application of approximately 300 TMS pulses during beta-ERD resulted in a significant increase of corticospinal excitability. By contrast, the identical stimulation pattern applied independent of beta-ERD in the control experiment resulted in a decrease of corticospinal excitability. These effects persisted beyond the period of stimulation and the depotentiation task.
  
  
  
  These results could be instrumental in developing new therapeutic approaches such as the application of closed-loop stimulation in the context of neurorehabilitation.
authors.affiliation: Division of Functional and Restorative Neurosurgery, and Centre for Integrative Neuroscience, Eberhard Karls University, Tuebingen, Germany.
authors.forename: Dominic
authors.initials: D
authors.lastname: Kraus
authors.affiliation: Division of Functional and Restorative Neurosurgery, and Centre for Integrative Neuroscience, Eberhard Karls University, Tuebingen, Germany.
authors.forename: Georgios
authors.initials: G
authors.lastname: Naros
authors.affiliation: Division of Functional and Restorative Neurosurgery, and Centre for Integrative Neuroscience, Eberhard Karls University, Tuebingen, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Bauer
authors.affiliation: Division of Functional and Restorative Neurosurgery, and Centre for Integrative Neuroscience, Eberhard Karls University, Tuebingen, Germany.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Khademi
authors.affiliation: Division of Functional and Restorative Neurosurgery, and Centre for Integrative Neuroscience, Eberhard Karls University, Tuebingen, Germany.
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Leão
authors.affiliation: Department of Neurology and Stroke, and Hertie Institute for Clinical Brain Research, Eberhard Karls University, Tuebingen, Germany.
authors.forename: Ulf
authors.initials: U
authors.lastname: Ziemann
authors.affiliation: Division of Functional and Restorative Neurosurgery, and Centre for Integrative Neuroscience, Eberhard Karls University, Tuebingen, Germany. Electronic address: alireza.gharabaghi@uni-tuebingen.de.
authors.forename: Alireza
authors.initials: A
authors.lastname: Gharabaghi
mesh_terms: D000328:Adult; D062207:Brain-Computer Interfaces; D004569:Electroencephalography / Q000379:methods; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D005385:Fingers; D006801:Humans; D036881:Long-Term Synaptic Depression; D008297:Male; D009044:Motor Cortex / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology; D010507:Periodicity; D011712:Pyramidal Tracts / Q000502:physiology*; D066191:Sensorimotor Cortex / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation / Q000379:methods*; D055815:Young Adult
keywords: Beta-band; Brain state-dependent stimulation; Brain–computer interface; Closed-loop stimulation; Event-related desynchronization; Motor cortex plasticity; Sensorimotor rhythm