Guidance of visual direction by topographical vibrotactile cues on the torso |
| |
Authors: | Francois Asseman Adolfo M Bronstein Michael A Gresty |
| |
Institution: | (1) Division of Neuroscience and Mental, Department of Clinical Neuroscience, Imperial College London, Charing Cross Campus, Fulham Palace Road, London, W6 8RF, UK |
| |
Abstract: | Vibration on localised areas of skin can be used to signal spatial orientation, multi-directional motion and also to guide
arm and hand movements. This study investigated the possibility that vibration at loci on the skin might also be used to cue
gaze direction. Eight subjects made eye or (head + eye) gaze saccades in the dark cued by vibration stimulation at discrete
loci spaced on a horizontal contour across the chest. Saccade and gaze amplitudes, latencies, and directions were analysed.
In the first experiment, performed without training, subjects could only use vibration cues to direct their gaze in cardinal
directions and gross quadrature. There was a high variability in the relationship between locus on the trunk and gaze direction
in space, both within and between subjects. Saccade latencies ranged from 377 to 433 ms and were related to the loci of vibration;
the further from the body midline the quicker the response. Since the association of skin loci with gaze direction did not
appear intuitive a sub-group of four subjects were retested after intensive training with feedback until they attained criterion
on midline ≡ 0° and 15 cm (to right/left of midline) ≡ 45° gaze shifts right and left. Training gave a moderate improvement
in directional specificity of gaze to a particular locus on the skin. Gaze direction was linearly rescaled with respect to
skin loci but variability and saccade latencies remained high. The uncertainty in the relationship between vibration locus
and gaze direction and the prolonged latencies of responses indicate circuitous neuronal processing. There appears to be no
pre-existing stimulus-response compatibility mapping between loci on the skin and gaze direction. Vibrotactile cues on the
skin of the trunk only serve a gross indication of visual direction in space. |
| |
Keywords: | Gaze Ocular Spatial orientation Somatosensory Vibrotactile-cueing Prostheses |
本文献已被 PubMed SpringerLink 等数据库收录! |
|