Cerebellum-mediated trainability of eye and head movements for dynamic gazing

PLoS One. 2019 Nov 4;14(11):e0224458. doi: 10.1371/journal.pone.0224458. eCollection 2019.

Abstract

Objective: To investigate whether gaze stabilization exercises (GSEs) improve eye and head movements and whether low-frequency cerebellar repetitive transcranial magnetic stimulation (rTMS) inhibits GSE trainability.

Methods: 25 healthy adults (real rTMS, n = 12; sham rTMS, n = 13) were recruited. Real or sham rTMS was performed for 15 min (1 Hz, 900 stimulations). The center of the butterfly coil was set 1 cm below the inion in the real rTMS. Following stimulation, 10 trials of 1 min of a GSE were conducted at 1 min intervals. In the GSE, the subjects were instructed to stand upright and horizontally rotate their heads according to a beeping sound corresponding to 2 Hz and with a gaze point ahead of them. Electrooculograms were used to estimate the horizontal gaze direction of the right eye, and gyroscopic measurements were performed to estimate the horizontal head angular velocity during the GSE trials. The percentage change from the first trial of motion range of the eye and head was calculated for each measurement. The percent change of the eye/head range ratio was calculated to assess the synchronous changes of the eye and head movements as the exercise increased.

Results: Bayesian two-way analysis of variance showed that cerebellar rTMS affected the eye motion range and eye/head range ratio. A post hoc comparison (Bayesian t-test) showed evidence that the eye motion range and eye/head range ratio were reduced in the fifth, sixth, and seventh trials compared with the first trial sham stimulation condition.

Conclusions: GSEs can modulate eye movements with respect to head movements, and the cerebellum may be associated with eye-head coordination trainability for dynamic gazing during head movements.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bayes Theorem
  • Cerebellum / physiology*
  • Electrooculography
  • Female
  • Fixation, Ocular / physiology*
  • Head Movements / physiology*
  • Healthy Volunteers
  • Humans
  • Male
  • Transcranial Magnetic Stimulation
  • Young Adult

Grant support

This work was supported by JSPS KAKENHI Grant Number JP17K01541 and partially supported by the Japan Agency for Medical Research and Development (AMED) under Grant Number JP19dm0307007. Tokuyukai Medical Corporation provided support in the form of salaries for authors N.Y. and S.N., but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.