Affiliations: [a] Department of Psychology and the Neuroscience Research Centre, University of Otago, New Zealand | [b] Department of Pharmacology, School of Medical Sciences, University of Otago Medical School, Dunedin, New Zealand
Note: [*] Reprint address: Dr. C.L. Darlington, University of Otago, Department of Paychology, Dunedin, New Zealand. Tel.: +64 3479 7630; Fax: +64 3479 8335; E-mail: cynthia@psy.otago.ac.nz
Abstract: Previous studies have shown that experience with optokinetic stimulation can alter a subject's sensitivity to illusions such as circularvection (CV). The aim of the present experiment was to compare optokinetic nystagmus (OKN), optokinetic afternystagmus (OKAN), and sensitivity to CV between 2 groups of sportspeople: 1) squash players (n=16), who regularly experience vigorous optokinetic stimulation while engaging in their sporting activity, and 2) weightlifters (n=16), whose sport does not involve the same degree of optokinetic stimulation as squash, but who nevertheless have to achieve a high degree of physical skill. OKN, OKAN (frequency, slow phase velocity, and timeconstant), and latency to CV (Stage 2 and Stage 3) were measured using electro-oculographic recording inside an optokinetic drum. Contrary to predictions,there were no significant differences in OKN, OKAN, or latency to CV between the 2 groups. These results suggest that 1) the practice effects that alter the sensitivity to CV may decay relatively quickly, and 2) differences in recreational sporting activities between subjects may not be a significant confounding factor in visual-vestibular interaction experiments.
