Long-range neural activity evoked by premotor cortex stimulation: a TMS/EEG co-registration study

Abstract

The premotor cortex is one of the fundamental structures composing the neural networks of the human brain. It is implicated in many behaviors and cognitive tasks, ranging from movement to attention and eye-related activity. Therefore, neural circuits that are related to premotor cortex have been studied to clarify their connectivity and/or role in different tasks. In the present work, we aimed to investigate the propagation of the neural activity evoked in the dorsal premotor cortex using transcranial magnetic stimulation/electroencephalography (TMS/EEG). Toward this end, interest was focused on the neural dynamics elicited in long-ranging temporal and spatial networks. Twelve healthy volunteers underwent a single-pulse TMS protocol in a resting condition with eyes closed, and the evoked activity, measured by EEG, was compared to a sham condition in a time window ranging from 45 ms to about 200 ms after TMS. Spatial and temporal investigations were carried out with sLORETA. TMS was found to induce propagation of neural activity mainly in the contralateral sensorimotor and frontal cortices, at about 130 ms after delivery of the stimulus. Different types of analyses showed propagated activity also in posterior, mainly visual, regions, in a time window between 70 and 130 ms. Finally, a likely “rebounding” activation of the sensorimotor and frontal regions, was observed in various time ranges. Taken together, the present findings further characterize the neural circuits that are driven by dorsal premotor cortex activation in healthy humans.

Phase-Amplitude Coupling of Neural Oscillations can be Effectively Probed with Concurrent TMS-EEG

“…Alongside the described local effects of sTMS and rTMS, we found that TMS can enhance population-level measures of phase-amplitude coupling over various other cortical sites. In line with this finding, propagation of neural activation related to either sTMS or rTMS has been shown in a number of previous studies [13,14,[49][50][51][52][53][54]. In particular, should follow the brain's intrinsic organizational structure, which is characterized by frequency-specific functional networks [55].…”

Daily iTBS worsens hand motor training — A combined TMS, fMRI and mirror training study

“…Both dPMCs are involved in motor learning in healthy subjects and stroke patients (Stagg and Johansen-Berg, 2013;Stefan et al, 2008;Stinear et al, 2009;Wang et al, 2014;Zanon et al, 2013). We are already aware of the involvement of the underlying network in hand motor training in a mirror (mirror training, MT): In an fMRI study we found higher effective connectivity between both dPMCs with the supplementary motor area (SMA) and M1 left when the right hand was trained in a mirror (Hamzei et al, 2012b).…”

Maturation changes the excitability and effective connectivity of the frontal lobe: A developmental TMS–EEG study

“…In healthy adults, TMS of the frontal cortex elicits a waveform showing several TEP components and lasting at least up to 300 ms (Massimini et al, ; Rogasch et al, ; Rogasch, Daskalakis, & Fitzgerald, ). Both the dorsolateral frontal cortex (Cash et al, ; Fitzgerald et al, ; Kähkönen et al, ; Lioumis, Kicic, Savolainen, Mäkelä, & Kähkönen, ; Rogasch et al, ) and superior frontal cortex or premotor area (Casarotto et al, ; Ferrarelli et al, ; Massimini et al, ; Zanon, Battaglini, Jarmolowska, Pizzolato, & Busan, ) have been targeted. Despite this methodological difference, a sequence containing deflections (named after their latency and polarity; N = negative, P = positive) at around 30 ms (P30), 40–50 ms (N45), 60 ms (P60), 100–120 ms (N100), and 160–190 ms (P180) is frequently reported in response to frontal cortex stimulation (Kähkönen, Komssi, Wilenius, & Ilmoniemi, ; Lioumis et al, ; Noda et al, ; Rogasch et al, ).…”