JN Fuel your research with LabChart
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
 QUICK SEARCH:   [advanced]


     


J Neurophysiol (March 28, 2007). doi:10.1152/jn.01321.2006
This Article
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
97/6/4341    most recent
01321.2006v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Seemungal, B. M
Right arrow Articles by Bronstein, A. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Seemungal, B. M
Right arrow Articles by Bronstein, A. M.
Submitted on December 16, 2006
Accepted on March 15, 2007

VESTIBULAR PERCEPTION AND NAVIGATION IN THE CONGENITALLY BLIND

Barry M Seemungal1, Stefan Glasauer2, Michael Gresty3, and Adolfo M. Bronstein4*

1 Imperial College, London, London, United Kingdom
2 Ludwig-Maximilians Univ, Germany
3 Imperial College, London
4 Imperial College, London, United States

* To whom correspondence should be addressed. E-mail: a.bronstein{at}imperial.ac.uk.

Vestibular input is required for accurate locomotion in the dark yet blind subjects’ vestibular function is unexplored. Such investigation may also identify visually-dependent aspects of vestibular function. We assessed vestibular function perceptually in six congenitally blind (and twelve sighted) subjects. Cupula deflection by a transient angular, horizontal acceleration generates a related vestibular nerve signal that declines exponentially with time constant {approx}4-7s which is prolonged to 15s in the evoked vestibular-ocular reflex by the brainstem ‘velocity storage’. We measured perceptual velocity storage in blind subjects following velocity steps (overall perceptual vestibular time constant, Experiment 1) and found it to be significantly shorter (5.34s; range 2.39--8.58s) than in control sighted subjects (15.8s; P<0.001). Vestibular navigation was assessed by subjects steering a motorised Barany-chair in response to imposed angular displacements in a path-reversal task, ‘Go-Back-to-Start’ (GBS:Experiment 2); and a path-completion task, ‘Complete-the-Circle’ (CTC:Experiment 3). GBS performances (comparing response vs stimulus displacement regression slopes and r2) were equal between groups (P>0.05) but the Blind showed worse CTC performance (P<0.05). Two blind individuals showed ultrashort perceptual time constants, high lifetime physical activity scores and superior CTC performances; we speculate that these factors may be inter-related. In summary, the vestibular velocity storage as measured perceptually, is visually dependent. Early blindness does not affect path reversal performance but is associated with worse path completion, a task requiring an absolute spatial strategy. Although congenitally blind subjects are overall less able to utilize spatial mechanisms during vestibular navigation, prior extensive physical spatial activity may enhance vestibular navigation.







HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Visit Other APS Journals Online
Copyright © 2007 by the The American Physiological Society.