Anticipatory modulation of neck muscle reflex responses induced by mechanical perturbations of the human forehead

Rieko Kuramochi, Toshitaka Kimura, Kimitaka Nakazawa, Masami Akai, Suguru Torii, Shuji Suzuki

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

The aim of this study was to test whether anticipation of upcoming head blow stimuli, which elicit reflex responses in the neck muscle, makes the reflex responses greater or not. In nine healthy subjects the reflex responses were elicited in the sternocleidomastoid (SCM) muscle in the eyes-open (EO) and eyes-closed (EC) conditions, which corresponded to the predictable and unpredictable conditions, respectively. The subjects were instructed not to resist the perturbations after the impact. The results demonstrated that the reflex response of the SCM muscle was significantly smaller in the predictable EO condition than in the unpredictable EC condition (P < 0.05), although no significant differences were observed in either the background EMG activities or the head accelerations. Further, this effect of anticipation was observed only in the later reflex EMG component, which most probably mediated the stretch reflex pathway. In contrast, no significant difference was observed in the early component, which was presumed to be the vestibular-collic reflex. The reduced stretch reflex response was suggested to be functionally relevant to the task requirement, i.e., to let the neck extension movement occur, and not to resist after the impact of the head blow. It was concluded that the anticipation has an effect on reducing the stretch reflex responses in the neck muscle, but does not have any effect on the presumed vestibular-collic reflex under the present experimental paradigm. It is suggested that the gain of the stretch reflex pathway is modulated by anticipatory information of upcoming mechanical event.

Original languageEnglish
Pages (from-to)206-210
Number of pages5
JournalNeuroscience Letters
Volume366
Issue number2
DOIs
Publication statusPublished - 2004 Aug 12

Keywords

  • Anticipatory modulation
  • Human
  • Neck muscle
  • Stretch reflex
  • Vestibular-collic reflex

ASJC Scopus subject areas

  • Neuroscience(all)

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