• Top page
  • Timetable
  • Per session
  • Per presentation
  • How to
  • Meeting Planner



Sensorimotor Control

開催日 2014/9/11
時間 18:00 - 19:00
会場 Room H(304)
Chairperson(s) 花川 隆 / Takashi Hanakawa (国立精神・神経医療研究センター脳病態統合イメージングセンター 先進脳画像研究部 / Department of Advanced Neuroimaging, Integrative Brain Imaging Center, National Center of Neurology and Psychiatry, Japan)
高草木 薫 / Kaoru Takakusaki (旭川医科大学医学部 脳機能医工学研究センター / Asahikawa Medical University, The Center for Brain Function and Medical Engineering, Japan)

Spinal interneuronal organization involved in the control of postural muscle tone in the cat

  • O1-H-6-3
  • 高草木 薫 / Kaoru Takakusaki:1 千葉 龍介 / Ryousuke Chiba:1 野津 司 / Tsukasa Nozu:2 奥村 利勝 / Toshikatsu Okumura:3 
  • 1:旭川医科大学・脳機能医工学研究センター / Res Ctr for Brain Funct. & Med. Eng., Asahikawa Med. Univ., Asahikawa, Japan 2:旭川医科大学・地域連携医療・教育学講座 / Dept Regional Med and Edu, Asahikawa Med Univ, Asahikawa, Japan 3:旭川医科大学・総合診療部 / Dept Gen Med, Asahikawa Med Univ, Asahikawa, Japan 

In the decerebrate cat preparation, microinjection of carbachol into the pontine reticular formation (PRF) induced muscular atonia by modulating the activities of reticulospinal neurons in the medullary reticular formation (MRF). The present study was designed to understand spinal interneuronal mechanisms involved in the control of postural muscle tone. For this purpose, extracellular activities of 105 interneurons were recorded from the lower lumbar segments (L6-L7) of acute decerebrate cats (n=28). Interneurons were divided into 3 types following inputs from the inhibitory region of the MRF and from peripheral sensory afferents. Type I cells (n=39) received excitation from the MRF and inhibition from volleys in flexion reflex afferents (FRA). They were located in the ventromedial part of the grey matter (lamina VII and VIII of the Rexed). Type II cells (n=38) received inhibition from the MRF. Type III cells (n=28) did not receive input from the MRF. Type II and III cells were located in the intermediate region (lamina IV-VII) and dorsal horn (lamina III) and exclusively received excitation from FRA. Firing rates of these groups of cells were further examined before and after injections carbachol into the PRF. In the state of decerebrate rigidity, Type I cells were silent or had low firing rates (2.0 ± 2.7 Hz; n=18). However, spontaneous firing was observed in Type II cells (38 ± 11.5 Hz; n=13) and Type III cells (21.4 ± 10.0 Hz; n=7). During carbachol-induced atonia, firing rates of the Type I cells was increased to 33 ± 11.7 Hz, while those of the Type II and III cells were reduced to 7.1 ± 5.2 Hz and 10.1 ± 5.8 Hz, respectively. These findings suggest the presence of functional topographical organization of spinal interneurons with respect to the control of postural muscle tone. Interneurons in the ventromedial grey matter (Type I cells) may be involved in muscular atonia, while those in dorsal horn and intermediate region (Type II and III cells) may contribute to maintenance of muscle tone.

Copyright © Neuroscience2014. All Right Reserved.