The neuroanatomical correlates of training-related perceptuo-reflex uncoupling in dancers.
Bottom Line: Adaptation to repeated whole-body rotations, for example, ballet training, is known to reduce vestibular responses.Voxel-based morphometry showed a selective gray matter (GM) reduction in dancers' vestibular cerebellum correlating with ballet experience.Dancers' vestibular cerebellar GM density reduction was related to shorter perceptual responses (i.e. positively correlated) but longer VOR duration (negatively correlated).
Affiliation: Neuro-Otology Unit, Division of Brain Sciences, Imperial College London, London W6 8RP, UK.Show MeSH
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Mentions: For each individual, we obtained simultaneous measures of the eye movement and perceptual responses to an angular velocity step (Okada et al. 1999; Fig. 1A). These behavioral data were then subsequently used to explore relationships with the brain structure. Whole-body rotations in the dark called “velocity steps” are frequently used in the clinical assessment of vestibular function (Fig. 1A). A velocity step consists of a rapid change in angular velocity. In our experiment, we used a standard clinical velocity step that involves rotating the subject from rest, that is, starting from a “constant” 0°/s and going to a “constant” 90°/s over 0.5 s. This velocity step evokes both reflexive eye movements (VOR) and a perception of self-rotation. The slow-phase eye velocity and perception of self-rotation responses are maximal at the onset of the velocity step and then subsequently decay in an exponential fashion, such that both responses are typically zero after 60 s. Since after 60 s of continued constant angular velocity (90°/s) rotation, there is no longer any vestibular activation (i.e. there is no VOR response and subjects feel that they are no longer turning), a second velocity step can be obtained by rapidly stopping the subject (from 90°/s to 0°/s over 0.5 s). This “stopping response” velocity step evokes perceptual and VOR responses that are identical in magnitude to those induced by the starting response, but are now oppositely directed. A minimum 60-s interval was used between the velocity steps. If nystagmus or turning of the wheel was observed after 60 s, then the recording was continued until the responses had dissipated before the next velocity step was applied.Figure 1.
Affiliation: Neuro-Otology Unit, Division of Brain Sciences, Imperial College London, London W6 8RP, UK.