Task-and intensity-dependent modulation of arm-trunk neural interactions in the corticospinal pathway in humans

Atsushi Sasaki, Naotsugu Kaneko, Yohei Masugi, Tatsuya Kato, Matija Milosevic, Kimitaka Nakazawa

Research output: Contribution to journalArticlepeer-review

Abstract

Most human movements require coordinated activation of multiple muscles. Although many studies reported associations between arm, leg, and trunk muscles during functional tasks, their neural interaction mechanisms still remain unclear. Therefore, the aim of our study was to investigate arm-trunk or arm-leg neural interactions in the corticospinal tract during different arm muscle contractions. Specifically, we examined corticospinal excitability of the erector spinae (ES; trunk extensor), rectus abdominis (RA; trunk flexor), and tibialis anterior (TA; leg) muscles while participants exerted: (1) wrist flexion and (2) wrist extension isometric contraction at various contraction intensity levels ranging from rest to 50% of maximal voluntary contraction (MVC) effort. Corticospinal excitability was assessed using motor evoked potentials (MEPs) elicited through motor cortex transcranial magnetic stimulation (TMS). Results showed that ES MEPs were facilitated even at low contractions (>5% MVC) during wrist flexion and extension, while stronger contractions (>25% MVC) were required to facilitate RA MEPs. The extent of facilitation of ES MEPs depended on contraction intensity of wrist exten-sion, but not flexion. Moreover, TA MEPs were facilitated at low contractions (>5% MVC) during wrist flexion and extension, but contraction intensity dependence was only shown during stronger wrist extension contractions (>25% MVC). In conclusion, trunk extensor corticospinal excitability seems to depend on the task and the intensity of arm contraction, while this is not true for trunk flexor and leg muscles. Our study therefore demonstrated task-and intensity-dependent neural interactions of arm-trunk connections, which may underlie anatomic and/or functional substrates of these muscle pairs.

Original languageEnglish
Article numberENEURO.0111-21.2021
JournaleNeuro
Volume8
Issue number5
DOIs
Publication statusPublished - 2021 Sep 1

Keywords

  • Arm-trunk interaction
  • Corticospinal pathway
  • Motor evoked potential
  • Transcranial magnetic stimulation

ASJC Scopus subject areas

  • Neuroscience(all)

Fingerprint

Dive into the research topics of 'Task-and intensity-dependent modulation of arm-trunk neural interactions in the corticospinal pathway in humans'. Together they form a unique fingerprint.

Cite this