Time-frequency analysis of short-lasting modulation of EEG induced by intracortical and transcallosal paired TMS over motor areas

Abstract

Dynamic changes in spontaneous electroencephalogram (EEG) rhythms can be seen to occur with a high rate of variability. An innovative method to study brain function is by triggering oscillatory brain activity with transcranial magnetic stimulation (TMS). EEG-TMS coregistration was performed on five healthy subjects during a 1-day experimental session that involved four steps: baseline acquisition, unconditioned single-pulse TMS, intracortical inhibition (ICI, 3 ms) paired-pulse TMS, and transcallosal stimulation over left and right primary motor cortex (M1). A time-frequency analysis based on the wavelet method was used to characterize rapid modifications of oscillatory EEG rhythms induced by TMS. Single, paired, and transcallosal TMS applied on the sensorimotor areas induced rapid desynchronization over the frontal and central-parietal electrodes mainly in the alpha and beta bands, followed by a rebound of synchronization, and rapid synchronization of delta and theta activity. Wavelet analysis after a perturbation approach is a novel way to investigate modulation of oscillatory brain activity. The main findings are consistent with the concept that the human motor system may be based on networklike oscillatory cortical activity and might be modulated by single, paired, and transcallosal magnetic pulses applied to M1, suggesting a phenomenon of fast brain activity resetting and triggering of slow activity.

Characterization of Glutamatergic and GABAA-Mediated Neurotransmission in Motor and Dorsolateral Prefrontal Cortex Using Paired-Pulse TMS–EEG

“…Paus et al (2001) found no influence of SICI on TEPs however that study may have been underpowered as only five participants survived rejection. Manganotti et al (2012) explored the influence of SICI on TMS-EEG potentials on a broader time-scale of seconds rather than Figure 4 Facilitatory influence of ICF on TEPs with TMS over DLPFC. (a) Group averaged TEPs following TS (red; delivered at a time equal to 0 ms), ICF (CS.TS) (blue) and CS alone (dotted line; delivered at -10 ms, ie, 10 ms prior to TS).…”

“…Studies have explored the electrophysiological TMS-EEG correlates of SICI and ICF in M1 (Ferreri et al, 2011;Manganotti et al, 2012;Paus et al, 2001). One of these studies explored SICI and ICF at sufficiently high temporal resolution and with adequate power to identify changes in TEP components (Ferreri et al, 2011).…”

Exploring Cortical Plasticity and Oscillatory Brain Dynamics via Transcranial Magnetic Stimulation and Resting-State Electroencephalogram

“…The advantage of scalp EEG over functional neuroimaging is its high temporal resolution of less than a millisecond, which enables real-time brain behavioural analysis (17). Moreover, EEG can directly record brain electrical activity, it is relatively inexpensive, and is simple to record.…”

“…Moreover, EEG can directly record brain electrical activity, it is relatively inexpensive, and is simple to record. The EEG signal does not come from action potentials of the cortical neurons but from the electrical potentials of the pyramidal dendrites of the cortex (17). The electrical potentials are generated by the summed inhibitory and excitatory postsynaptic potentials from the pyramidal neurons of the cerebral cortex that produce electrical dipoles between the soma and the apical dendrites.…”

New Perspectives in Transcranial Magnetic Stimulation: Epilepsy, Consciousness and the Perturbational Approach

“…On a finer temporal scale, TMS-EEG may enable time-locking of TMS to a specific phase of an underlying EEG signal while testing the time course of EEG reactivity to the magnetic pulse [46,47,61,62]. Recently, time-frequency analysis has led to a better understanding of the effect of brain stimulation on brain oscillatory rhythms, with a rapid desynchronization of activity in the alpha and beta bands and a rapid synchronization of delta and theta activity [63].…”