Optokinetic Rotation Research Articles

Prolonged Static Whole-Body Roll-Tilt and Optokinetic Stimulation Significantly Bias the Subjective Postural Vertical in Healthy Human Subjects.

Background: Prolonged static whole-body roll-tilt has been shown to bias estimates of the direction of gravity when assessed by static paradigms such as the subjective visual vertical and the subjective haptic vertical.Objective: We hypothesized that these shifts are paradigm-independent and thus predicted a post-tilt bias as well for self-adjustments along perceived vertical (subjective postural vertical, SPV). Likewise, rotatory optokinetic stimuli, which have been shown to shift the SPV when presented at the time of adjustments, may have an lasting effect on the SPV, predicting a shift in the perceived direction of gravity in the direction of the optokinetic rotatory stimulation.Methods: Self-adjustments along perceived vertical by use of a motorized turntable were recorded at baseline and after 5 min of static whole-body roll-tilt (orientation = ±90°, adaptation period) in 10 healthy human subjects. During adaptation subjects were either in darkness (no OKN stimulation) or were presented a full-field rotatory optokinetic stimulus (velocity = ±60°/s). Statistical analysis of adjustment errors for the different conditions was performed using a generalized linear model.Results: After 5 min of static whole-body roll-tilt in darkness, we observed significant (p < 0.001) shifts in the SPV averaging −2.8° (adaptation position: −90°) and 3.1° (+90°), respectively. Adding an optokinetic rotatory stimulus resulted in an additional, significant shift of SPV adjustments toward the direction of the previously presented optokinetic rotation (optokinetic clockwise rotation: 1.4°, p = 0.034; optokinetic counter-clockwise rotation: −1.3°, p = 0.037). Trial-to-trial variability of turntable adjustments was not significantly affected by adaptation.Conclusions: Prolonged static roll-tilt results in a significant post-tilt bias of the perceived direction of gravity when assessed by the SPV, confirming previous findings from other vision-dependent and vision-independent paradigms. This finding emphasizes the impact of recent whole-body roll orientations relative to gravity. Such adaptational shifts in verticality estimates may be explained in the context of Bayesian optimal observer theory with a bias of prior knowledge (i.e., expectation biased by experience). Our findings also have clinical implications, as the observed post-tilt bias may contribute to postural instability when standing up in the morning with an increasing risk for falls and fall-related injuries in humans with preexisting balance disorders.

Contributions of optostatic and optokinetic cues to the perception of vertical.

While it has been well established that optostatic and optokinetic cues contribute to the perception of vertical, it is unclear how the brain processes their combined presence with the nonvisual vestibular cues. Using a psychometric approach, we examined the percept of vertical in human participants (n = 17) with their body and head upright, presented with a visual frame tilted at one of eight orientations (between ±45°, steps of 11.25°) or no frame, surrounded by an optokinetic roll-stimulus (velocity = ±30°/s or stationary). Both cues demonstrate relatively independent biases on vertical perception, with a sinusoidal modulation by frame orientation of ~4° and a general shift of ~1-2° in the rotation direction of the optic flow. Variability was unaffected by frame orientation but was higher with than without optokinetic rotation. An optimal-observer model in which vestibular, optostatic, and optokinetic cues provide independent sources to vertical perception was unable to explain these data. In contrast, a model in which the optokinetic signal biases the internal representation of gravity, which is then optimally integrated with the optostatic cue, provided a good account, at the individual participant level. We conclude that optostatic and optokinetic cues interact differently with vestibular cues in the neural computations for vertical perception.NEW & NOTEWORTHY Static and dynamic visual cues are known to bias the percept of vertical, but how they interact with vestibular cues remains to be established. Guided by an optimal-observer model, the present results suggest that optokinetic information is combined with vestibular information into a single, vestibular-optokinetic estimate, which is integrated with an optostatically derived estimate of vertical.

Effects of retention intervals on the magnitude of optokinetic rotation-induced taste aversions.

This study investigated the effects of different retention intervals on the magnitude of optokinetic rotation-induced conditioned taste aversions in humans. Two experiments were conducted. In Exp. 1, 20 subjects were divided into two groups, a CS-UCS group in which drinking soybean milk was paired with optokinetic rotation-induced gastric illness and a CS-Only group in which drinking soybean milk was not paired with optokinetic rotation. Analysis indicated that two days after pairing soybean milk drinking with optokinetic rotation, the subjects in the CS-UCS group had significantly reduced palatability ratings of soybean milk and lower consumption of soybean milk than those in the CS-Only group. In Exp. 2, 40 subjects were divided into four CS-UCS groups with 1-day, 3-day, 5 day, and 10-day retention intervals between the session of pairing soybean milk with optokinetic rotation and the session of retasting soybean milk. Analysis yielded no significant differences among four groups on palatability of soybean milk and consumption of soybean milk in the retasting session. It is concluded that optokinetic rotation is an effective unconditioned stimulus for conditioned taste aversions formation and that the aversion has a retention period of at least 10 days.

Susceptibility to motion sickness induced by optokinetic rotation and self-rotation by walking around a vertical pole.

31 subjects viewed an optokinetic rotating drum for 12 min. in one session and self-rotated by walking quickly around a vertical pole with eyes closed while alternately flexing and extending the neck in another session. The self-rotation session contained 6 trials (3 clockwise and 3 counterclockwise rotations). Each trial contained 20 cycles of self-rotations. Self-reported ratings of nausea and symptoms of motion sickness were obtained for each session. The subjects developed symptoms of nausea, sweating, dizziness, headache, drowsiness, and changes in salivation in both drum rotation and self-rotation sessions. However, the subjects reported higher ratings of nausea in the session of optokinetic rotation than in the session of self-rotation around a vertical pole. These results indicated that both optokinetic rotation and self-rotation with eyes closed while alternately flexing and extending the neck are effective means of inducing nausea and motion sickness.

Adaptation to optokinetic rotation-induced motion sickness without experiencing nausea.

17 subjects highly susceptible to motion sickness were divided into Nausea and No-nausea groups depending upon whether the subjects experienced nausea during adaptation to nauseagenic rotation. Eight subjects in the Nausea group viewed an optokinetic rotation drum for repeated sessions of 16 min., with an interval of two days between every two sessions. During each session the subjects continuously viewed the rotating drum 16 min. even if they experienced nausea. nine subjects in the No-nausea group likewise viewed an optokinetic rotation drum for at most 16 min. but immediately stopped viewing the rotating drum whenever they experienced nausea during the session. The criteria for full adaptation were that the subject reported no feelings of stomach discomfort and nausea during a 16-min session. The mean number of sessions to reach full adaptation was 3.9 (SD = 0.6) with a range 3 to 5 sessions for the subjects in the Nausea group and 3.2 (SD = 0.8) with a range 2 to 4 for the subjects in the No-nausea group. It was concluded that subjects can adapt to a nauseagenic optokinetic rotation by repeated exposure without experiencing nausea and vomiting during adaptation.

P6 acupressure reduces nausea and gastric tachyarrhythmia provoked by optokinetic rotation

P6 acupressure reduces nausea and gastric tachyarrhythmia provoked by optokinetic rotation

Nausea and gastric tachyarrhythmia induced by optokinetic rotation correlate to past history of motion sickness: T.S. Hoffman, S. Hu, K.M. Glaser, T.M. Stanton. Department of Psychology, Humboldt State University, Arcata, CA

Nausea and gastric tachyarrhythmia induced by optokinetic rotation correlate to past history of motion sickness: T.S. Hoffman, S. Hu, K.M. Glaser, T.M. Stanton. Department of Psychology, Humboldt State University, Arcata, CA

ネコ水平眼運動系におけるａｓｃｅｎｄｉｎｇ ｔｒａｃｔ ｏｆ Ｄｅｉｔｅｒｓ’の関与について

There are two distinct excitatory projections to the medial rectus (MR) motoneuron pool from the posterior brain stem in the cat. First, abducens internuclear neurons send their axons into the contralateral medial longitudinal fasciculus to terminate upon MR motoneurons. Secondly, the ascending tract of Deiters' (ATD) also terminates upon MR motoneurons.We studied the effects of a unilateral ATD lesion on the horizontal eye movements evoked by optokinetic and vestivular stimuli. ENGs were recorded prior to and after the lesion was induced in the fully alert cat. The eye velocity on the side of the lesion during the slow and fast phases was compared with that of the intact side. The lesion to the ATD was confirmed histologically and physiologically.The lesion of the right ATD resulted in the following: (1) During clockwise OKN stimulation (optokinetic rotation to the right), the slow phase eye velocity on the side of the lesion was slower than that of the intact side, while the fast phase eye velocity was not affected. (2) During counterclockwise stimulation, neither the slow nor fast phase eye velocity of either side was affected. (3) During caloric stimulation, slow and fast phase eye velocity was not changed. On the basis of these data, we concluded that ATD was one of the final pathways mediating the visual signals responsible for OKN.