1. Gamma-transcranial alternating current stimulation and theta-burst stimulation: inter-subject variability and the role of BDNF
- Author
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Francesco Asci, Simona Petrucci, Valentina D'Onofrio, Antonio Suppa, Alfredo Berardelli, Andrea Guerra, Monia Ginevrino, and Alessandro Zampogna
- Subjects
Adult ,Male ,tACS ,Genotype ,CTBS ,chemical and pharmacologic phenomena ,Stimulation ,Inter-subject variability ,Transcranial Direct Current Stimulation ,Polymorphism, Single Nucleotide ,050105 experimental psychology ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,stomatognathic system ,Neurotrophic factors ,BDNF ,gamma ,plasticity ,theta-burst stimulation ,Physiology (medical) ,Neuromodulation ,Neuroplasticity ,Gamma Rhythm ,Humans ,Medicine ,0501 psychology and cognitive sciences ,Theta Rhythm ,Transcranial alternating current stimulation ,Neuronal Plasticity ,business.industry ,Brain-Derived Neurotrophic Factor ,05 social sciences ,Motor Cortex ,Evoked Potentials, Motor ,Sensory Systems ,stomatognathic diseases ,medicine.anatomical_structure ,Neurology ,Facilitation ,Female ,Neurology (clinical) ,Primary motor cortex ,business ,Neuroscience ,030217 neurology & neurosurgery - Abstract
Objective The main limitation of neuromodulation techniques is inter-subject variability. Combining theta-burst stimulation (TBS) with gamma-transcranial alternating current stimulation (γ-tACS) allows to shape cortical plasticity. However, it is unknown whether γ-tACS modifies TBS-induced response variability. In this study, we measured the inter-subject variability of TBS-γ tACS and controlled the effect of the Brain-Derived Neurotrophic Factor (BDNF) Val66Met polymorphism. Methods Intermittent TBS (iTBS)-sham tACS, iTBS-γ tACS, continuous TBS (cTBS)-sham tACS, and cTBS-γ tACS were applied in randomised sessions. Inter-subject variability was measured using grand average and clustering methods. TBS-γ tACS effects on motor evoked potentials (MEP) were compared between Val/Val and Met carriers. Results We found that γ-tACS boosted iTBS-induced MEP facilitation and cancelled cTBS-induced MEP depression. Grand average analysis showed that γ-tACS prominently increased the percentage of iTBS responders and cTBS non-responders. The clustering method demonstrated that TBS-γ tACS response varied between subjects, a phenomenon unrelated to the BDNF genotype. Conclusions Enhancing γ oscillations through tACS boosts iTBS-induced LTP-like plasticity and suppresses cTBS-induced LTD-like plasticity of the primary motor cortex in a reliable manner. The BDNF Val66Met polymorphism does not influence these effects. Significance Since γ-tACS significantly increases the number of iTBS responders, it may be used in clinical settings.
- Published
- 2020