Human cortical theta reactivity to high‐frequency repetitive transcranial magnetic stimulation

Abstract

Electroencephalography (EEG) can directly monitor the temporal progression of cortical changes induced by repetitive Transcranial Magnetic Stimulation (rTMS) and facilitate the understanding of cortical and subcortical influences in the genesis of oscillations. In this combined rTMS/EEG study, we aimed to investigate changes in oscillatory activity after high-frequency ($11 Hz) rTMS relative to the number of applied pulses. Twenty intermittent trains of 20 or 60 rTMS pulses were delivered over the human primary motor cortex at rest and tuned to individual mu frequency. The regional and interregional oscillatory neural activity after stimulation were evaluated using event-related power (ERPow) and event-related coherence (ERCoh) transformations. The most prominent changes for ERPow were observed in the theta band (4-7 Hz), as an increase in ERPow up to 20 s following 60 rTMS pulses, whereas ERPow increases were smaller in mu (10-12 Hz) and beta (13-30 Hz). ERCoh revealed that rTMS 60 modulated the connectivity in the theta band for up to 20 s. The topography of mu and theta changes were not identical; mu was more focal and theta was more global. Our data suggested the presence of independent cortical theta and mu generators with different reactivity to rTMS but could not rule out possible thalamocortical contributions in generating theta and mu over the motor network. Hum Brain Mapp 33:2224-2237, in Wiley Online Library (wileyonlinelibrary.com). V C 2011 Wiley Periodicals, Inc. r Cortical Theta Reactivity to rTMS r r 2225 r r Noh and Fuggetta r r 2228 r r Cortical Theta Reactivity to rTMS r r 2229 r r Noh and Fuggetta r r 2230 r r Cortical Theta Reactivity to rTMS r r 2235 r r Noh and Fuggetta r r 2236 r

Long Lasting Modulation of Cortical Oscillations after Continuous Theta Burst Transcranial Magnetic Stimulation

“…This supported our previous study that showed a higher cortical oscillations of θ (4–7 Hz) compared to µ (10–12 Hz) and β (13–30 Hz) up to 20 seconds after intermittent trains of 60 pulses of high frequency magnetic stimulation (∼ 11 Hz) to the primary motor cortex at rest [26]. We proposed that the increase in θ power modulation may be due to the independent theta generators that are not confined to the hippocampus but also present near the brain surface as demonstrated by animal studies [40], [41], and human intracranial EEG recordings [41]–[44].…”

Inhibiting corticospinal excitability by entraining ongoing mu-alpha rhythm in motor cortex

“…This was not the case for local alpha power at the source level where we found the alpha and beta power increase only in rhythmic rTMS. Our findings are in line with previous studies where participants received conventional stimulation intensities of rTMS (80-100% of resting motor threshold) applied over the left M1 at rest [22,23].…”

Can noninvasive brain stimulation enhance cognition in neuropsychiatric disorders?

“…This work served as a demonstration of the effect of rTMS on regional and interregional synaptic transmission via the induction of cortical oscillations. More recent work by Azila Noh and Fugetta demonstrated broader effects of high frequency rTMS (11 Hz) on theta, mu, and beta frequency bands. Sokhadze et al (2009) further applied these techniques to demonstrate the potential therapeutic benefit of rTMS in autism to provide a means of altering neuronal plasticity through a presumed mechanism of enhanced cortical gamma oscillations.…”