A comparison of sensorimotor adaptation in the visual and in the auditory modality.

Gerd Schmitz,Otmar Bock

doi:10.1371/journal.pone.0107834

Gerd Schmitz, Otmar Bock

Open Access

https://doi.org/10.1371/journal.pone.0107834

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Abstract

We compared sensorimotor adaptation in the visual and the auditory modality. Subjects pointed to visual targets while receiving direct spatial information about fingertip position in the visual modality, or they pointed to visual targets while receiving indirect information about fingertip position in the visual modality, or they pointed to auditory targets while receiving indirect information about fingertip position in the auditory modality. Feedback was laterally shifted to induce adaptation, and aftereffects were tested with both target modalities and both hands. We found that aftereffects of adaptation were smaller when tested with the non-adapted hand, i.e., intermanual transfer was incomplete. Furthermore, aftereffects were smaller when tested in the non-adapted target modality, i.e., intermodal transfer was incomplete. Aftereffects were smaller following adaptation with indirect rather than direct feedback, but they were not smaller following adaptation with auditory rather than visual targets. From this we conclude that the magnitude of adaptive recalibration rather depends on the method of feedback delivery (indirect versus direct) than on the modality of feedback (visual versus auditory).

Highlights

Visuo-motor adaptation is typically examined by asking subjects to point with their hand at visual targets while visual feedback of the hand is distorted
The present work compares the adaptation of pointing movements in the visual and in the auditory modality
Data from the baseline phase confirm that our auditory paradigm was effective: subjects pointed with auditory feedback to auditory targets as accurately as they did with visual feedback to visual targets

Summary

Introduction

Visuo-motor adaptation is typically examined by asking subjects to point with their hand at visual targets while visual feedback of the hand is distorted. Upon removal of the distortion aftereffects emerge They are typically measured during movements with undistorted or even without feedback, and are interpreted as recalibration of sensorimotor transformation rules, unbiased by strategic adjustments [1]. We have recently observed that aftereffects are smaller when they are assessed with auditory rather than with visual targets [7], and proposed two interpretations for this finding: aftereffects either are smaller in the auditory than in the visual modality, or they are smaller in an unpracticed than in the previously practiced modality. The present work overcomes this problem by exposing some subjects to a visuo-motor and others to an audio-motor distortion, and testing for aftereffects in all subjects both with visual and with auditory targets, in counterbalanced order

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