Brain-robot interface driven plasticity: Distributed modulation of corticospinal excitability.
Brain-robot interfaces (BRI) are studied as novel interventions to facilitate functional restoration in patients with severe and persistent motor deficits following stroke. They bridge the impaired connection in the sensorimotor loop by providing brain-state dependent proprioceptive feedback with orthotic devices attached to the hand or arm of the patients. The underlying neurophysiology of this BRI neuromodulation is still largely unknown. We investigated changes of corticospinal excitability with transcranial magnetic stimulation in thirteen right-handed healthy subjects who performed 40min of kinesthetic motor imagery receiving proprioceptive feedback with a robotic orthosis attached to the left hand contingent to event-related desynchronization of the right sensorimotor cortex in the β-band (16-22Hz). Neural correlates of this BRI intervention were probed by acquiring the stimulus-response curve (SRC) of both motor evoked potential (MEP) peak-to-peak amplitudes and areas under the curve. In addition, a motor mapping was obtained. The specificity of the effects was studied by comparing two neighboring hand muscles, one BRI-trained and one control muscle. Robust changes of MEP amplitude but not MEP area occurred following the BRI intervention, but only in the BRI-trained muscle. The steep part of the SRC showed an MEP increase, while the plateau of the SRC showed an MEP decrease. MEP mapping revealed a distributed pattern with a decrease of excitability in the hand area of the primary motor cortex, which controlled the BRI, but an increase of excitability in the surrounding somatosensory and premotor cortex. In conclusion, the BRI intervention induced a complex pattern of modulated corticospinal excitability, which may boost subsequent motor learning during physiotherapy.
Division of Functional and Restorative Neurosurgery & Division of Translational Neurosurgery, Department of Neurosurgery, Eberhard Karls University Tuebingen, Germany; Neuroprosthetics Research Group, Werner Reichardt Centre for Integrative Neuroscience, Eberhard Karls University Tuebingen, Germany.
Dominic
D
Kraus
Division of Functional and Restorative Neurosurgery & Division of Translational Neurosurgery, Department of Neurosurgery, Eberhard Karls University Tuebingen, Germany; Neuroprosthetics Research Group, Werner Reichardt Centre for Integrative Neuroscience, Eberhard Karls University Tuebingen, Germany.
Georgios
G
Naros
Division of Functional and Restorative Neurosurgery & Division of Translational Neurosurgery, Department of Neurosurgery, Eberhard Karls University Tuebingen, Germany; Neuroprosthetics Research Group, Werner Reichardt Centre for Integrative Neuroscience, Eberhard Karls University Tuebingen, Germany.
Robert
R
Bauer
Division of Functional and Restorative Neurosurgery & Division of Translational Neurosurgery, Department of Neurosurgery, Eberhard Karls University Tuebingen, Germany; Neuroprosthetics Research Group, Werner Reichardt Centre for Integrative Neuroscience, Eberhard Karls University Tuebingen, Germany.
Maria Teresa
MT
Leão
Department of Neurology and Stroke, and Hertie Institute for Clinical Brain Research, Eberhard Karls University Tuebingen, Germany.
Ulf
U
Ziemann
Division of Functional and Restorative Neurosurgery & Division of Translational Neurosurgery, Department of Neurosurgery, Eberhard Karls University Tuebingen, Germany; Neuroprosthetics Research Group, Werner Reichardt Centre for Integrative Neuroscience, Eberhard Karls University Tuebingen, Germany. Electronic address: alireza.gharabaghi@uni-tuebingen.de.
Alireza
A
Gharabaghi
D000328:Adult; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D062207:Brain-Computer Interfaces; D004569:Electroencephalography; D058407:Electroencephalography Phase Synchronization / Q000502:physiology; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology; D056228:Feedback, Sensory / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D009473:Neuronal Plasticity / Q000502:physiology*; D011712:Pyramidal Tracts / Q000502:physiology*; D012371:Robotics / Q000379:methods; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult
Brain–computer interface; Brain–machine interface; Brain–robot interface; Corticospinal excitability; EEG; Event-related desynchronization; Plastic reorganization; Stimulus–response curve