Asymmetric short-term adaptation of the vertical vestibulo-ocular reflex in humans

We study here the effect of a short-term training paradigm on the gain and phase of the human translational VOR (the linear VOR: LVOR). Subjects were exposed to lateral sinusoidal translations on a sled, at 0.5 Hz, 0.3 g peak acceleration. With subjects tracking a remembered target at 1.2 m, the LVOR (slow-phase) under these conditions typically has a phase lead or lag, and a gain that falls short of compensatory. To induce short-term adaptation (training), we presented an earth-fixed visual scene at 1.2 m during sinusoidal translation ( × 1 viewing) for 20 minutes, so as to drive the LVOR toward compensatory phase and gain. We examined both the slow-phase and the saccadic responses to these stimuli. Testing after training showed changes in slow-component gain and phase which were mostly but not always in the compensatory direction. These changes were more consistent in naive subjects than in subjects who had previous LVOR experience. Changes in gain were seen with step as well as sinusoidal test stimuli; gain changes were not correlated with vergence changes. There was a strong correlation between gain changes and phase changes across subjects. Fast phases (catch-up saccades) formed a large component of the LVOR under our testing conditions (approximately 30% of the changes in gain but not in phase due to training.

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Short-term vestibulo-ocular reflex adaptation in humans

Experimental Brain Research ◽

10.1007/bf00227202 ◽

1994 ◽

Vol 100 (2) ◽

Cited By ~ 47

Author(s):

Mark Shelhamer ◽

Caroline Tiliket ◽

Dale Roberts ◽

PhillipD. Kramer ◽

DavidS. Zee

Keyword(s):

Short Term ◽

Ocular Reflex ◽

Vestibulo Ocular Reflex

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Short-term vestibular responses to repeated rotations

Journal of Vestibular Research ◽

10.3233/ves-2000-10103 ◽

2000 ◽

Vol 10 (1) ◽

pp. 17-23

Author(s):

Seung Cheol Ahn ◽

Chae Yong Lee ◽

Dong Wook Kim ◽

Moo Hoo Lee

Keyword(s):

Time Constant ◽

Phase Changes ◽

Short Term ◽

Mean Values ◽

Ocular Reflex ◽

Group I ◽

Vestibulo Ocular Reflex ◽

The Mean ◽

Group Ii ◽

Sinusoidal Rotations

To investigate the short-term vestibular habituation, we performed the 4 successive velocity step tests on 28 volunteers, the peak velocity of which was 100 deg/sec with acceleration and deceleration of 100 deg / sec 2 . As the repeated rotations might alter the vestibulo-ocular reflex (VOR), sinusoidal rotations at a frequency of 0.16 Hz were also given before and after the 4 successive velocity step tests to investigate the changes of gain and phase of VOR. The 28 volunteers were divided into two groups, group I and II, according to their responses to repeated rotations. In group I (25 subjects, mean age 23.7 year), the mean values of the slow cumulative eye position (SCEP), the time integral of eye velocity during nystagmus, was reduced after each trial of the 4-successive velocity step tests as follows; 403.4 ± 29 degree (1st trial), 346.2 ± 37 degree (2nd trial), 278.3 ± 33 degree (3rd trial) and 256.6 ± 36 degree (4th trial). The time constant of the nystagmus was also reduced as follows; 12.9 ± 0.78 second (1st trial), 12 ± 0.63 second (2nd trial), 9.7 ± 0.78 second (3rd trial) and 9.9 ± 0.54 second (4th trial). In group II (3 subjects, mean age 28.3 year), the mean values of SCEP gradually increased; 774.3 ± 135 degree (1st trial), 1127 ± 178 degree (2nd trial), 1096.3 ± 123.4 degree (3rd trial) and 1225.7 ± 199.7 degree (4th trial). The time constant of the nystagmus increased; 15.7 ± 2.7 second (1st trial), 22 ± 4.5 second (2nd trial), 22.3 ± 3.3 second (3rd trial) and 23.3 ± 5.7 second (4th trial). The gain of vestibulo-ocular reflex (VOR) induced by sinusoidal rotations at a frequency 0.16 Hz increased in both groups: 0.59 ± 0.03 to 0.78 ± 0.06 (group I) and 0.65 ± 0.07 to 1.15 ± 0.06 (group II). Phase changes were also observed. In group I, the phase was shifted from 0.6 ± 0.6 degree to − 0.40 ± 0.6 degree. In group II, the phase was shifted from 3.67 ± 1.86 degree to − 0.33 ± 0.33 degree. The repeated rotation did not induce a common nystagmic response in all subjects. Thus, person to person variations should be considered in short term vestibular habituation.

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