Repetitive paired associative stimulation (rPAS) repeatedly pairs electrical nerve stimulation (ENS) with transcranial magnetic stimulation (TMS) of the contralateral motor hand area (M1) at 5 Hz frequency. So far, there are only few studies concerning the effects of PAS on the modulation of EEG power. Hence, aim of the present study was to investigate rPAS long term after-effects on cortical excitability looking at EEG power spectra. In four experimental sessions, separated by 2 weeks interval, 12 awake subjects received rPAS of the right median nerve and left M1 at a fixed interval (ISI) of 25 ms (real condition), 5 Hz-TMS on left M1, 5 Hz-ENS, of the right median nerve, and rPAS with changing ISI (sham condition). We measured peak-to-peak MEP amplitude, evoked from the target muscle (right abductor pollicis brevis muscle) at rest and the absolute power (POW) in four frequency bands: α (8-12 Hz), β (13-30), θ (4-7) and δ (1-3), under rest conditions. All these parameters were evaluated in three detection blocks: baseline, immediately after and after 30' from the end of the conditioning protocol. Real rPAS induced a long-lasting homotopic cortical excitability modulation, as indexed by MEP amplitude increase, that was paralleled by a long-lasting reduction of α/β-POW and by a widespread θ-δ-POW modulation. rPAS applied over the sensory-motor cortex induced an LTP-like plasticity, as indexed by a robust reduction in the α/β POW positively correlated with the MEP amplitude increase. rPAS25ms may be a useful tool for motor neurorehabilitation promoting a sensory-motor coupling within β oscillations.

A Local Signature of LTP-Like Plasticity Induced by Repetitive Paired Associative Stimulation

Manganotti, Paolo;
2015

Abstract

Repetitive paired associative stimulation (rPAS) repeatedly pairs electrical nerve stimulation (ENS) with transcranial magnetic stimulation (TMS) of the contralateral motor hand area (M1) at 5 Hz frequency. So far, there are only few studies concerning the effects of PAS on the modulation of EEG power. Hence, aim of the present study was to investigate rPAS long term after-effects on cortical excitability looking at EEG power spectra. In four experimental sessions, separated by 2 weeks interval, 12 awake subjects received rPAS of the right median nerve and left M1 at a fixed interval (ISI) of 25 ms (real condition), 5 Hz-TMS on left M1, 5 Hz-ENS, of the right median nerve, and rPAS with changing ISI (sham condition). We measured peak-to-peak MEP amplitude, evoked from the target muscle (right abductor pollicis brevis muscle) at rest and the absolute power (POW) in four frequency bands: α (8-12 Hz), β (13-30), θ (4-7) and δ (1-3), under rest conditions. All these parameters were evaluated in three detection blocks: baseline, immediately after and after 30' from the end of the conditioning protocol. Real rPAS induced a long-lasting homotopic cortical excitability modulation, as indexed by MEP amplitude increase, that was paralleled by a long-lasting reduction of α/β-POW and by a widespread θ-δ-POW modulation. rPAS applied over the sensory-motor cortex induced an LTP-like plasticity, as indexed by a robust reduction in the α/β POW positively correlated with the MEP amplitude increase. rPAS25ms may be a useful tool for motor neurorehabilitation promoting a sensory-motor coupling within β oscillations.
14-set-2014
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https://link.springer.com/article/10.1007/s10548-014-0396-0
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11368/2979377
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