Demonstration of short-term plasticity in the dorsolateral prefrontal cortex with theta burst stimulation: A TMS-EEG study

Abstract

2 Highlights• Effects of iTBS and cTBS were studied in the DLPFC using TMS-EEG• iTBS increased N120 amplitude, theta power and LICI of theta• cTBS decreased theta power alone . CC-BY 4.0 International license not peer-reviewed) is the author/funder. It is made available under a The copyright holder for this preprint (which was . http://dx.doi.org/10.1101/101097 doi: bioRxiv preprint first posted online 3 Abstract Objectives: To examine the effects of intermittent TBS (iTBS) and continuous TBS (cTBS) on cortical reactivity in the dorsolateral prefrontal cortex.Methods: 10 healthy participants were stimulated with either iTBS, cTBS or sham at F3 electrode. Single-and paired-pulse TMS and concurrent electroencephalography (EEG) were used to assess change in cortical reactivity and long-interval intracortical inhibition (LICI) via TMS-evoked potentials (TEPs) and TMS-evoked oscillations.Results: Significant increases in N120 amplitudes (p < 0.01) were observed following iTBS over prefrontal cortex. Changes in TMS-evoked theta oscillations and LICI of theta oscillations were also observed following iTBS (increase) and cTBS (decrease). Change in LICI of theta oscillations correlated with change in N120 amplitude following TBS (r = -0.670, p = 0.001). Conclusions:This study provides preliminary evidence that TBS produces direct changes in cortical reactivity in the prefrontal cortex. Combining TBS with TMS-EEG may be a useful approach to optimise stimulation paradigms prior to the conduct of clinical trials.

Influence of theta-burst transcranial magnetic stimulation over the dorsolateral prefrontal cortex on emotion processing in healthy volunteers

“…The stimulation intensity was set as 80% AMT, a value sufficiently strong to elicit an excitatory response (Bakker et al, 2015;Conte et al, 2014;Chung et al, 2017a;Chung et al, 2017b;Huang et al, 2005;Padberg & George, 2009). For the real iTBS, the coil was centred on F3 electrode at a 45°angle from the midline (Chung et al, 2017a;Fitzgerald et al, 2009), to elicit the strongest response (Thomson et al, 2013). For sham stimulation, the coil was oriented at 90°to the scalp so that the electromagnetic field was tangential to the head (Chung et al, 2017a).…”

“…For the real iTBS, the coil was centred on F3 electrode at a 45°angle from the midline (Chung et al, 2017a;Fitzgerald et al, 2009), to elicit the strongest response (Thomson et al, 2013). For sham stimulation, the coil was oriented at 90°to the scalp so that the electromagnetic field was tangential to the head (Chung et al, 2017a).…”

Default mode network alterations after intermittent theta burst stimulation in healthy subjects

“…Beyond local effects under the stimulation coil, plasticity changes in brain's altered functional connectivity away from the stimulation point, e.g. the DLPFC 13 , are likely relevant to the treatment of depression, which has been associated with aberrant brain functional connectivity 14 . The default-mode network (DMN), consisting of the medial prefrontal cortex, posterior cingulate cortex, and areas of posterior parietal cortex 15 .…”

Impact of different intensities of intermittent theta burst stimulation on the cortical properties during TMS‐EEG and working memory performance

“…Recent advances in technology have enabled the measurement of plastic neuronal changes following neuromodulatory paradigms using concurrent recording of electroencephalographic responses to TMS (TMS‐EEG) (Chung, Rogasch, Hoy, & Fitzgerald, ; Farzan et al, ; Hill, Rogasch, Fitzgerald, & Hoy, ). Each TMS pulse elicits a TMS‐evoked EEG response, and the change in the amplitude of TMS‐evoked potentials (TEPs) and the power of TMS‐evoked oscillations following TBS provide metric of plasticity in the prefrontal cortex (Chung et al, ). TEPs are composed of several components which are thought to represent excitatory and inhibitory postsynaptic potentials.…”

“…A negative trough at a latency of approximately 100 ms (N100) has been associated with inhibitory mechanisms in motor (Bonnard, Spieser, Meziane, de Graaf, & Pailhous, ; Premoli et al, ; Rogasch, Daskalakis, & Fitzgerald, ) and prefrontal cortex (Chung et al, ; Rogasch, Daskalakis, & Fitzgerald, ), and is considered to be the most robust TEP component with the best signal to noise ratio (SNR) (Noda et al, ). Modulation of this component has been observed following TBS over the prefrontal cortex (Chung et al, ) and cerebellum (Casula et al, ; Harrington & Hammond‐Tooke, ). Recent studies also suggest that a peak at a latency of 60 ms (P60) may be a correlate of neuronal excitability in motor cortex (Cash et al, ) and DLPFC (Hill, Rogasch, Fitzgerald, & Hoy, ).…”