Possible Mechanisms Underlying the Therapeutic Effects of Transcranial Magnetic Stimulation

Abstract

Transcranial magnetic stimulation (TMS) is an effective method used to diagnose and treat many neurological disorders. Although repetitive TMS (rTMS) has been used to treat a variety of serious pathological conditions including stroke, depression, Parkinson’s disease, epilepsy, pain, and migraines, the pathophysiological mechanisms underlying the effects of long-term TMS remain unclear. In the present review, the effects of rTMS on neurotransmitters and synaptic plasticity are described, including the classic interpretations of TMS effects on synaptic plasticity via long-term potentiation and long-term depression. We also discuss the effects of rTMS on the genetic apparatus of neurons, glial cells, and the prevention of neuronal death. The neurotrophic effects of rTMS on dendritic growth and sprouting and neurotrophic factors are described, including change in brain-derived neurotrophic factor concentration under the influence of rTMS. Also, non-classical effects of TMS related to biophysical effects of magnetic fields are described, including the quantum effects, the magnetic spin effects, genetic magnetoreception, the macromolecular effects of TMS, and the electromagnetic theory of consciousness. Finally, we discuss possible interpretations of TMS effects according to dynamical systems theory. Evidence suggests that a rTMS-induced magnetic field should be considered a separate physical factor that can be impactful at the subatomic level and that rTMS is capable of significantly altering the reactivity of molecules (radicals). It is thought that these factors underlie the therapeutic benefits of therapy with TMS. Future research on these mechanisms will be instrumental to the development of more powerful and reliable TMS treatment protocols.

Repetitive transcranial magnetic stimulation of the dorsolateral prefrontal cortex enhances working memory

“…Immediate neural effects include acute and transient changes in the electrical state of the stimulated neurons (Chervyakov et al 2015). In addition, repetitive TMS causes slow and long-lasting neuroplastic changes of the stimulated area following multiple TMS treatment sessions.…”

Transcranial magnetic stimulation for treatment of major depression during pregnancy: a review

“…17 TMS is based on the general principle that stimulation or inhibition of a cortical target could modulate the brain circuits that mediate functions related to the pathophysiology of depression 17 with effects on neurotransmitters and synaptic plasticity (via long-term potentiation and long-term depression); the genetic apparatus of neurons, glial cells, and the prevention of neuronal death; dendritic growth and sprouting; and neurotrophic factors. 18 The evidence suggests that best response is achieved when the intervention is performed for acute episodes and in people less than 65 years old for whom treatment with antidepressants has failed or only achieved a partial response. 19 …”

The application of high-frequency and iTBS transcranial magnetic stimulation for the treatment of spasticity in the patients presenting with secondary progressive multiple sclerosis

“…Предполагается, что эффекты рТМС связаны в первую очередь с процес-сами долговременной депрессии и потенциации [13][14][15][16][17][18]. Также рассматривается возможность влия-ния самого магнитного поля на моторную кору че-рез различные механизмы [19]. Кроме того, в ряде работ показано, что возбуждающее воздействие на моторную кору режима iTBS межимпульсным ин-тервалом в 200 мс связано с торможением гамма-аминомасляной кислоты (ГАМК) [20,21].…”