Acute TMS/fMRI response explains offline TMS network effects – An interleaved TMS-fMRI study

Tik, Martin; Woletz, Michael; Schuler, Anna‐Lisa; Vasileiadi, Maria; Cash, Robin; Zalesky, Andrew; Lamm, Claus; Windischberger, Christian

doi:10.1016/j.neuroimage.2022.119833

Cited by 26 publications

(18 citation statements)

References 59 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Interestingly, three of five measures (Exc_ind, sample entropy and alpha power) showed a larger E/I increase in the regions contralateral to the iTBS target, than in the left M1. This is in line with recent TMS-fMRI findings (Tik et al 2023) and might reflect some compensatory mechanisms.…”

Section: Discussionsupporting

confidence: 93%

“…Secondly, when exploring non-eloquent cortices, concurrent neuroimaging measurements are necessary to measure the response to stimuli. Simultaneous TMS-Electroencephalography (TMS-EEG) (Giambattistelli et al 2014; Tremblay et al 2019), TMS-functional magnetic resonance imaging (TMS-fMRI) (Tik et al 2023; Mizutani-Tiebel et al 2022) and TMS-functional near-infrared spectroscopy (TMS-fNIRS) (Cai et al 2022) are among the most common options (Bergmann et al 2016), but the data acquisition process is long and difficult. Neuroimaging signals are affected by artifacts, and there is uncertainty on the extent to which neuroimaging metrics align with the classical definition of cortical excitability (Cai et al 2022; Conde et al 2019).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Assessing cortical excitability with electroencephalography: a pilot study with EEG-iTBS

Pellegrino,

Schuler,

Cai

et al. 2023

Preprint

View full text Add to dashboard Cite

Cortical excitability measures neural reactivity to stimuli, usually delivered via Transcranial Magnetic Stimulation (TMS). Excitation/inhibition balance (E/I) is the ongoing equilibrium between excitatory and inhibitory activity of neural circuits. According to some studies, E/I could be estimated in-vivo and non-invasively through the modeling of electroencephalography (EEG) signals. Several measures have been proposed (phase consistency in the gamma band, sample entropy, exponent of the power spectral density 1/f curve, E/I index extracted from detrend fluctuation analysis, and alpha power). It remains to be investigated to what extent they scale with excitability and how they relate to each other. Intermittent theta burst stimulation (iTBS) of the primary motor cortex (M1) is a non-invasive neuromodulation technique allowing controlled and focal enhancement of cortical excitability and E/I of the stimulated hemisphere. M1 excitability and several E/I estimates extracted from resting state EEG recordings were assessed before and after iTBS in a cohort of healthy subjects. Enhancement of M1 excitability, as measured through motor-evoked potentials (MEPs), and phase consistency of the cortex in high gamma band correlated with each other. Other measures of E/I showed some expected results, but no correlation with TMS excitability measures or consistency with each other. EEG E/I estimates offer an intriguing opportunity to map cortical excitability non-invasively, with high spatio-temporal resolution and with a stimulus independent approach. While different EEG E/I estimates may reflect the activity of diverse excitatory-inhibitory circuits, spatial phase synchrony in the gamma band is the measure that best captures excitability changes in the primary motor cortex.

show abstract

Section: Discussionsupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Assessing cortical excitability with electroencephalography: a pilot study with EEG-iTBS

Pellegrino,

Schuler,

Cai

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…Due to the flexibility of our mTMS power electronics and coil design algorithms, we open a possibility for future designs with critical improvements in stimulus focality, which can elucidate better the underlying physiological and anatomical processes on the orientation sensitivity of the rat brain motor representations. This setup can be utilized to create and test a wide range of protocols to study whole-brain and network effects of neuromodulation (Bergmann et al, 2021; Mengotti et al, 2022; Tik et al, 2023; Yang et al, 2021) and treatments for neurological disorders (Dawson et al, 2018; Seewoo et al, 2018; Siddiqi et al, 2022).…”

Section: Discussionmentioning

confidence: 99%

“…EEG has high temporal resolution but offers limited spatial specificity, especially with rodents, and while PET provides higher spatial specificity than EEG, it requires radioactive tracers, hindering large-population studies. In turn, modern ultra-high-field MRI scanners offer superior spatial resolution compared to PET and EEG, enabling non-invasive network-level investigations of healthy and diseased brains (Bergmann et al, 2021; Gordon et al, 2023; Siebner et al, 2009; Tik et al, 2023).…”

Section: Introductionmentioning

confidence: 99%

A multi-channel TMS system enabling accurate stimulus orientation control during concurrent ultra-high-field MRI for preclinical applications

Souza,

Sinisalo,

Korhonen

et al. 2023

Preprint

View full text Add to dashboard Cite

Background: Monitoring cortical responses to neuromodulation protocols on preclinical models can elucidate fundamental mechanisms of brain function. Concurrent brain stimulation and imaging is challenging, usually compromising spatiotemporal resolution, accuracy, and versatility. Objective: We aimed to (1) develop and characterize a multi-channel transcranial magnetic stimulation (TMS) system with electronic control of neuromodulation parameters in a magnetic resonance imaging (MRI) environment, (2) characterize the interplay between the mTMS system and the MRI recordings, and (3) verify how different TMS pulse orientations evoke distinct muscle responses in an anesthetized rat. Methods: The multi-channel TMS system was designed using materials and electromagnetic safety mechanisms for compatibility with a 9.4-T scanner for small-animal MRI. To deliver the stimulation, we created a 2-coil transducer enabling electronic control of the induced electric field orientation in the rat's brain. The MRI compatibility was verified with a radiofrequency transceiver coil measuring MRI signals and the presence of imaging artifacts due to the stimulation pulses. We also investigated the effect of the multi-channel TMS pulse orientation on the motor responses of an anesthetized rat. Results: We showed that the stimulation pulses do not affect the anatomical imaging quality, and imaging signals are disrupted only if recorded before 10 ms after pulse delivery. Without physically rotating the coils, we demonstrated that the rat's motor responses considerably depended on the E-field orientation.

show abstract

“…Functional magnetic resonance imaging (fMRI) has also been used to document the acute impact of TMS on brain networks, 14 which has shown that rTMS‐induced functional changes tend to spread distally across and within networks 15,16 . Recently, a concurrent interleaved TMS/fMRI study was conducted with state‐of‐the‐science purpose‐designed MRI head coils to delineate networks and downstream regions activated by DLPFC‐TMS, and it was found that regions of increased acute signal activation during TMS resemble a resting‐state brain network 17 . These studies provided important progress highlighting the importance of wider network‐level consequences of TMS after site stimulation.…”

Section: Introductionmentioning

confidence: 99%

The acute effects of repetitive transcranial magnetic stimulation on laminar diffusion anisotropy of neocortical gray matter

Zhang

Liu

Zhao

et al. 2023

MedComm

View full text Add to dashboard Cite

Repetitive transcranial magnetic stimulation (rTMS) is increasingly used to treat neuropsychiatric disorders. Inhibitory and excitatory regimens have been both adopted but the exact mechanism of action remains unclear, and investigating their differential effects on laminar diffusion profiles of neocortex may add important evidence. Twenty healthy participants were randomly assigned to receive a low‐frequency/inhibitory or high‐frequency/excitatory rTMS targeting the left dorsolateral prefrontal cortex (DLPFC). With the brand‐new submillimeter diffusion tensor imaging of whole brain and specialized surface‐based laminar analysis, fractional anisotropy (FA) and mean diffusion (MD) profiles of cortical layers at different cortical depths were characterized before/after rTMS. Inhibitory and excitatory rTMS both showed impacts on diffusion metrics of somatosensory, limbic, and sensory regions, but different patterns of changes were observed—increased FA with inhibitory rTMS, whereas decreased FA with excitatory rTMS. More importantly, laminar analysis indicated laminar specificity of changes in somatosensory regions during different rTMS patterns—inhibitory rTMS affected the superficial layers contralateral to the DLPFC, while excitatory rTMS led to changes in the intermediate/deep layers bilateral to the DLPFC. These findings provide novel insights into acute neurobiological effects on diffusion profiles of rTMS that may add critical evidence relevant to different protocols of rTMS on neocortex.

show abstract

Acute TMS/fMRI response explains offline TMS network effects – An interleaved TMS-fMRI study

Cited by 26 publications

References 59 publications

Assessing cortical excitability with electroencephalography: a pilot study with EEG-iTBS

Assessing cortical excitability with electroencephalography: a pilot study with EEG-iTBS

A multi-channel TMS system enabling accurate stimulus orientation control during concurrent ultra-high-field MRI for preclinical applications

The acute effects of repetitive transcranial magnetic stimulation on laminar diffusion anisotropy of neocortical gray matter

Contact Info

Product

Resources

About