Neurobiological After-Effects of Non-Invasive Brain Stimulation

TITLE
Neurobiological After-Effects of Non-Invasive Brain Stimulation

AUTHORS
Cirillo G; Di Pino G; Capone F; Ranieri F; Florio L; Todisco V; Tedeschi G; Funke K; Di Lazzaro V. Institution Cirillo, G. I Division of Neurology, Department of Medical, Surgical, Neurological, Metabolic and Aging Sciences, Second University of Naples, Piazza Miraglia 2, 80138, Naples, Italy. Di Pino, G. Research Unit of Neurophysiology and Neuroengineering of Human-Technology Interaction, Department of Medicine, Universita Campus Bio-Medico di Roma, via Alvaro del Portillo 21, 00128, Rome, Italy; Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, Universita Campus Bio-Medico di Roma, via Alvaro del Portillo 21, 00128, Rome, Italy; Fondazione Alberto Sordi – Research Institute for Ageing, Via Alvaro del Portillo 5, 00128, Rome, Italy. Capone, F. Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, Universita Campus Bio-Medico di Roma, via Alvaro del Portillo 21, 00128, Rome, Italy; Fondazione Alberto Sordi – Research Institute for Ageing, Via Alvaro del Portillo 5, 00128, Rome, Italy. Ranieri, F. Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, Universita Campus Bio-Medico di Roma, via Alvaro del Portillo 21, 00128, Rome, Italy; Fondazione Alberto Sordi – Research Institute for Ageing, Via Alvaro del Portillo 5, 00128, Rome, Italy. Florio, L. Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, Universita Campus Bio-Medico di Roma, via Alvaro del Portillo 21, 00128, Rome, Italy; Fondazione Alberto Sordi – Research Institute for Ageing, Via Alvaro del Portillo 5, 00128, Rome, Italy. Todisco, V. I Division of Neurology, Department of Medical, Surgical, Neurological, Metabolic and Aging Sciences, Second University of Naples, Piazza Miraglia 2, 80138, Naples, Italy. Tedeschi, G. I Division of Neurology, Department of Medical, Surgical, Neurological, Metabolic and Aging Sciences, Second University of Naples, Piazza Miraglia 2, 80138, Naples, Italy. Funke, K. Department of Neurophysiology, Medical Faculty, Ruhr-University Bochum, Universitaetsstrasse 150, 44801, Bochum, Germany. Di Lazzaro, V. Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, Universita Campus Bio-Medico di Roma, via Alvaro del Portillo 21, 00128, Rome, Italy; Fondazione Alberto Sordi – Research Institute for Ageing, Via Alvaro del Portillo 5, 00128, Rome, Italy.

SOURCE
Brain Stimulation. 10(1):1-18, 2017 Jan – Feb.

BACKGROUND
In recent years, many studies have evaluated the effects of noninvasive brain stimulation (NIBS) techniques for the treatment of several neurological and psychiatric disorders. Positive results led to approval of NIBS for some of these conditions by the Food and Drug Administration in the USA. The therapeutic effects of NIBS have been related to bi-directional changes in cortical excitability with the direction of change depending on the choice of stimulation protocol. Although after-effects are mostly short lived, complex neurobiological mechanisms related to changes in synaptic excitability bear the potential to further induce therapy-relevant lasting changes.

OBJECTIVE
To review recent neurobiological findings obtained from in vitro and in vivo studies that highlight molecular and cellular mechanisms of short- and long-term changes of synaptic plasticity after NIBS.

FINDINGS
Long-term potentiation (LTP) and depression (LTD) phenomena by itself are insufficient in explaining the early and long term changes taking place after short episodes of NIBS. Preliminary experimental studies indicate a complex scenario potentially relevant to the therapeutic effects of NIBS, including gene activation/regulation, de novo protein expression, morphological changes, changes in intrinsic firing properties and modified network properties resulting from changed inhibition, homeostatic processes and glial function.

CONCLUSIONS
This review brings into focus the neurobiological mechanisms underlying long-term after-effects of repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) recently obtained from in vitro and in vivo studies, both in animals and humans.

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