Differential gating of slow postsynaptic and high-frequency spike-like components in human somatosensory evoked potentials under isometric motor interference.

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  • Additional Information
    • Source:
      Publisher: Elsevier/North-Holland Biomedical Press Country of Publication: Netherlands NLM ID: 0045503 Publication Model: Print Cited Medium: Print ISSN: 0006-8993 (Print) Linking ISSN: 00068993 NLM ISO Abbreviation: Brain Res Subsets: MEDLINE
    • Publication Information:
      Original Publication: Amsterdam Elsevier/North-Holland Biomedical Press.
    • Subject Terms:
      Evoked Potentials, Somatosensory/*physiology ; Excitatory Postsynaptic Potentials/*physiology ; Exercise/*physiology; Action Potentials/physiology ; Adult ; Electrophysiology ; Female ; Forearm/innervation ; Humans ; Male ; Median Nerve/physiology ; Recruitment, Neurophysiological/physiology ; Signal Transduction/physiology ; Somatosensory Cortex/physiology
    • Abstract:
      Human cortical somatosensory evoked potentials (SEP) can be modified by concomitant motor tasks ('gating'), through peripheral occlusion and/or central mechanisms. The present study aimed (1) at refining earlier results concerning motor-gating of the primary cortical EPSP-related N20 response after electric median nerve stimulation, and (2) at providing first data on motor-gating of the 600 Hz SEP wavelet burst which occurs superimposed onto N20 and primarily reflects repetitive cerebral population spikes. In 12 healthy subjects median nerve SEP were elicited, using electrical stimuli with intensities below, at and above motor threshold, under either rest or an isometric fist clenching task. Amplitude and latency modifications were analysed for the peripheral compound action potential (CAP), low-frequency SEP components (N20, P25, N35 and P70) and the high-frequency burst. While the peripheral CAP remained unchanged, isometric motor innervation significantly attenuated N20, P25 and P70 amplitudes and shortened peak latencies progressively for all components after N20. In contrast, the high-frequency 600 Hz burst was modulated neither in amplitude nor in latency. Regular amplitude recruitment occurred for all components independent from the motor task, excluding channel saturation as an explanation for gating. We suggest that SEP gating under isometric motor innervation is a central process which selectively operates on specific SEP components and could partly reflect an "efference copy" mechanism.
    • Publication Date:
      Date Created: 20011204 Date Completed: 20020219 Latest Revision: 20190614
    • Publication Date:
      20221213
    • Accession Number:
      10.1016/s0006-8993(01)03157-2
    • Accession Number:
      11730706