Repetitive transcranial magnetic stimulation (rTMS) is increasingly being used to promote cortical reorganization, under the assumption that it can induce long-term potentiation (LTP) of neural responses. This assumption is supported by several lines of indirect evidence. For example, rTMS of motor cortex can induce a potentiation of muscle motor evoked potentials that outlasts the stimulation by several minutes. In animal models, a direct demonstration of LTP is typically obtained by high-frequency electrical stimulation coupled with local field recordings of population responses. In this study, we exploited a new approach based on combined rTMS/high-density electroencephalography (hd-EEG) to obtain direct, noninvasive evidence for LTP in humans. Cortical responses to single TMS pulses were measured with hd-EEG before and after applying rTMS to motor cortex (5 Hz, 1500 pulses). The results demonstrate that, after rTMS, EEG responses at latencies of 15-55 ms were significantly potentiated. A topographic analysis revealed that this potentiation was significant at EEG electrodes located bilaterally over premotor cortex. Thus, these findings provide a direct demonstration in humans of LTP induced by rTMS.
A direct demonstration of cortical LTP in humans : A combined TMS/EEG study / S. Esser, R. Huber, M. Massimini, M. Peterson, F. Ferrarelli, G. Tononi. - In: BRAIN RESEARCH BULLETIN. - ISSN 0361-9230. - 69:1(2006 Mar 15), pp. 86-94.
A direct demonstration of cortical LTP in humans : A combined TMS/EEG study
M. Massimini;
2006
Abstract
Repetitive transcranial magnetic stimulation (rTMS) is increasingly being used to promote cortical reorganization, under the assumption that it can induce long-term potentiation (LTP) of neural responses. This assumption is supported by several lines of indirect evidence. For example, rTMS of motor cortex can induce a potentiation of muscle motor evoked potentials that outlasts the stimulation by several minutes. In animal models, a direct demonstration of LTP is typically obtained by high-frequency electrical stimulation coupled with local field recordings of population responses. In this study, we exploited a new approach based on combined rTMS/high-density electroencephalography (hd-EEG) to obtain direct, noninvasive evidence for LTP in humans. Cortical responses to single TMS pulses were measured with hd-EEG before and after applying rTMS to motor cortex (5 Hz, 1500 pulses). The results demonstrate that, after rTMS, EEG responses at latencies of 15-55 ms were significantly potentiated. A topographic analysis revealed that this potentiation was significant at EEG electrodes located bilaterally over premotor cortex. Thus, these findings provide a direct demonstration in humans of LTP induced by rTMS.Pubblicazioni consigliate
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