Andrea Guerra1, Antonio Suppa2, Matteo Bologna2, Valentina D'Onofrio1, Edoardo Bianchini1, Peter Brown3, Vincenzo Di Lazzaro4, Alfredo Berardelli5. 1. Department of Human Neuroscience, Sapienza University of Rome, Viale dell'Università 30, 00185, Rome, Italy. 2. Department of Human Neuroscience, Sapienza University of Rome, Viale dell'Università 30, 00185, Rome, Italy; IRCCS Neuromed Institute, Via Atinense 18, 86077, Pozzilli, IS, Italy. 3. Medical Research Council Brain Network Dynamics Unit and Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, OX3 9DU, United Kingdom. 4. Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, University Campus Bio-Medico, via Álvaro del Portillo 21, 00128, Rome, Italy. 5. Department of Human Neuroscience, Sapienza University of Rome, Viale dell'Università 30, 00185, Rome, Italy; IRCCS Neuromed Institute, Via Atinense 18, 86077, Pozzilli, IS, Italy. Electronic address: alfredo.berardelli@uniroma1.it.
Abstract
BACKGROUND: Transcranial Alternating Current Stimulation (tACS) consists in delivering electric current to the brain using an oscillatory pattern that may entrain the rhythmic activity of cortical neurons. When delivered at gamma frequency, tACS modulates motor performance and GABA-A-ergic interneuron activity. OBJECTIVE: Since interneuronal discharges play a crucial role in brain plasticity phenomena, here we co-stimulated the primary motor cortex (M1) in healthy subjects by means of tACS during intermittent theta-burst stimulation (iTBS), a transcranial magnetic stimulation paradigm known to induce long-term potentiation (LTP)-like plasticity. METHODS: We measured and compared motor evoked potentials before and after gamma, beta and sham tACS-iTBS. While we delivered gamma-tACS, we also measured short-interval intracortical inhibition (SICI) to detect any changes in GABA-A-ergic neurotransmission. RESULTS: Gamma, but not beta and sham tACS, significantly boosted and prolonged the iTBS-induced after-effects. Interestingly, the extent of the gamma tACS-iTBS after-effects correlated directly with SICI changes. CONCLUSIONS: Overall, our findings point to a link between gamma oscillations, interneuronal GABA-A-ergic activity and LTP-like plasticity in the human M1. Gamma tACS-iTBS co-stimulation might represent a new strategy to enhance and prolong responses to plasticity-inducing protocols, thereby lending itself to future applications in the neurorehabilitation setting.
BACKGROUND: Transcranial Alternating Current Stimulation (tACS) consists in delivering electric current to the brain using an oscillatory pattern that may entrain the rhythmic activity of cortical neurons. When delivered at gamma frequency, tACS modulates motor performance and GABA-A-ergic interneuron activity. OBJECTIVE: Since interneuronal discharges play a crucial role in brain plasticity phenomena, here we co-stimulated the primary motor cortex (M1) in healthy subjects by means of tACS during intermittent theta-burst stimulation (iTBS), a transcranial magnetic stimulation paradigm known to induce long-term potentiation (LTP)-like plasticity. METHODS: We measured and compared motor evoked potentials before and after gamma, beta and sham tACS-iTBS. While we delivered gamma-tACS, we also measured short-interval intracortical inhibition (SICI) to detect any changes in GABA-A-ergic neurotransmission. RESULTS: Gamma, but not beta and sham tACS, significantly boosted and prolonged the iTBS-induced after-effects. Interestingly, the extent of the gamma tACS-iTBS after-effects correlated directly with SICI changes. CONCLUSIONS: Overall, our findings point to a link between gamma oscillations, interneuronal GABA-A-ergic activity and LTP-like plasticity in the human M1. Gamma tACS-iTBS co-stimulation might represent a new strategy to enhance and prolong responses to plasticity-inducing protocols, thereby lending itself to future applications in the neurorehabilitation setting.
Authors: Alfredo Berardelli; Giovanni Abbruzzese; Robert Chen; Michael Orth; Michael C Ridding; Cathy Stinear; Antonio Suppa; Carlo Trompetto; Philip D Thompson Journal: Brain Stimul Date: 2008-07-01 Impact factor: 8.955
Authors: Simone Rossi; Andrea Antal; Sven Bestmann; Marom Bikson; Carmen Brewer; Jürgen Brockmöller; Linda L Carpenter; Massimo Cincotta; Robert Chen; Jeff D Daskalakis; Vincenzo Di Lazzaro; Michael D Fox; Mark S George; Donald Gilbert; Vasilios K Kimiskidis; Giacomo Koch; Risto J Ilmoniemi; Jean Pascal Lefaucheur; Letizia Leocani; Sarah H Lisanby; Carlo Miniussi; Frank Padberg; Alvaro Pascual-Leone; Walter Paulus; Angel V Peterchev; Angelo Quartarone; Alexander Rotenberg; John Rothwell; Paolo M Rossini; Emiliano Santarnecchi; Mouhsin M Shafi; Hartwig R Siebner; Yoshikatzu Ugawa; Eric M Wassermann; Abraham Zangen; Ulf Ziemann; Mark Hallett Journal: Clin Neurophysiol Date: 2020-10-24 Impact factor: 4.861