Intermittent theta-burst stimulation induces correlated changes in cortical and corticospinal excitability in healthy older subjects.

Intermittent theta-burst stimulation induces correlated changes in cortical and corticospinal excitability in healthy older subjects.

Clin Neurophysiol. 2017 Sep 28;128(12):2419-2427

Authors: Gedankien T, Fried PJ, Pascual-Leone A, Shafi MM

Abstract
OBJECTIVE: We studied the correlation between motor evoked potentials (MEPs) and early TMS-evoked EEG potentials (TEPs) from single-pulse TMS before and after intermittent Theta Burst Stimulation (iTBS) to the left primary motor cortex (M1) in 17 healthy older participants.
METHODS: TMS was targeted to the hand region of M1 using a MRI-guided navigated brain stimulation system and a figure-of-eight biphasic coil. MEPs were recorded from the right first dorsal interosseous muscle using surface EMG. TEPs were extracted from a 61-channel EEG recording. Participants received 90 single TMS pulses at 120% of resting motor threshold before and after iTBS.
RESULTS: Across all participants, the change in N15-P30 TEP and MEP amplitudes were significantly correlated (r=0.69; p<0.01). Average TEP responses did not change significantly after iTBS, whereas MEP amplitudes showed a significant increase.
CONCLUSIONS: Changes in corticospinal reactivity and cortical reactivity induced by iTBS are related. However, the effect of iTBS on TEPs, unlike MEPs, is not straightforward.
SIGNIFICANCE: Our findings help elucidate the relationship between changes in cortical and corticospinal excitability in healthy older individuals. Going forward, TEPs may be used to evaluate the effects of theta-burst stimulation in non-motor brain regions.

PMID: 29096215 [PubMed - as supplied by publisher]

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