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Biomedical subjects

W B Kulecz

Publications and source records attributed to W B Kulecz.

8 recordsLinked to original sources
PubMed1987

The role of saccular afferents in vertical optokinetic nystagmus in primates. A study in relation to optokinetic nystagmus in microgravity.

After bilateral sacculectomies, the squirrel monkey's vertical optokinetic nystagmus showed a gain increase of slow-phase down-nystagmus and a gain decrease of the slow-phase up-nystagmus. The nystagmus beating field of the former shifted upward but that of the latter did not change clearly. These results are in general agreement with the findings in man during the recent shuttle flight and indicate the functional linkage of saccular afferents to the vertical optokinetic nystagmus.

Afferent Pathways↗
PubMed1987

Role of otolith endorgans in the genesis of vestibular-visual conflict sickness (pitch) in the squirrel monkey (first report).

This experiment was designed to clarify each vestibular submodality's role in the genesis of vestibular-visual conflict sickness in pitch. We wanted to determine whether the ablation of the macula utriculi and macula sacculi, totally or separately, unilaterally and bilaterally, preserving the semicircular canals intact, could eliminate the conflict emesis in the squirrel monkey model. Observations were carried out over 5 months. In susceptible animals, the difference in conflict sickness scores between the pre- and the postutriculosacculectomy conditions was statistically significant. However, in less susceptible animals, the scores were low from the beginning and the differences were not statistically significant. Unilateral sacculectomy was performed at the smallest otolith endorgan lesion. The conflict sickness scores declined significantly and no emesis occurred. However, at 4.5 months after the operation, animals regained their preoperative scores; thus indicating that the afferents from the remaining endorgans were sufficient to provoke the sickness. This result indicated that functional neural adaptation took place within the equilibrium system. The trial repetition in normal animals and stapedectomized controls did not produce any clear score change.

Animals↗
PubMed1986

Vestibular-visual conflict in pitch and yaw planes in the squirrel monkey.

Direction conflicting vestibular and visual (optokinetic) stimuli either in the pitch or yaw plane were given to squirrel monkey subjects. The conflict sickness symptom score in the pitch plane was significantly higher than that in the yaw plane for the initial exposure session (p less than 0.01). A significant score difference was also encountered when the exposure sessions were repeated (p less than 0.05).

Animals↗
PubMedDate not supplied

The squirrel monkey stabilimetry.

In order to characterize postural ataxia associated with peripheral vestibular lesions, we have developed a T-perch recording system suitable for squirrel monkeys (tree-living primates). This system includes strain gauges for detecting movement of the vertical shaft in the directions of anterior-posterior and left-right. Simultaneously we recorded electroencephalogram (EEG), vertical eye movement, electrocardiogram (ECG) and respiration (by pneumography). Representative Dynographic records (obtained during sleep) after unilateral and bilateral (two-staged) labyrinthectomy showed the frequent occurrence of phasic body movements: slow deviations to the lesion side and the frontward and subsequent quick rightings which occurred almost synchronously with the sleep becoming shallow (judged by EEG).

Animals↗
PubMedDate not supplied

Vestibular-visual conflict sickness in the squirrel monkey.

When combined vestibular and visual (optokinetic) stimuli were given to squirrel monkeys in a direction and phase mismatching sinusoidal mode (in yaw plane), five of six monkeys exhibited actual emesis during three repeated exposures on separate trial days. Two animals vomited on two trial days and three animals, on one day. The incidence took place in 38.9% of the total trial days. When the identical vestibular and visual stimuli were given individually, the effect was negligible, thus confirming each stimulus magnitude was not stressful enough to produce emesis when used separately.

Animals↗
PubMedDate not supplied

Change in susceptibility to vestibular-visual conflict sickness in monkeys by repeated exposure.

Squirrel monkeys, susceptible to the vestibular-visual conflict sickness in pitch (with frank vomiting), were subjected to repeated exposure to pitch conflict in various modes and in a randomly mixed order (30 min daily, for 10 consecutive days). Immediately after the training, a significant decline in susceptibility was found, represented by reduced vomiting rates, reduced sickness scores, reduced salivation and improved regularity of vertical oculomotor responses. Susceptibility at the pre-training level returned when the test was repeated 10 days later. Temporary suppression of pitch conflict sickness susceptibility indicates the possibility of training crew members prior to their space flight missions to control the space motion sickness, particularly vomiting.

Animals↗
PubMedDate not supplied

Asymmetry of vertical optokinetic after-nystagmus in squirrel monkeys.

Asymmetry of vertical optokinetic after-nystagmus (OKAN) was studied in 6 squirrel monkeys. The slow-phase eye velocity (SPEV) of upward OKAN first-phase (OKAN-I) increased with increasing stimulus velocity, whereas the SPEV of downward OKAN-I diminished. The time constant of OKAN-I was shortened with the increase in stimulus speed in both directions. With a downward stimulus, the short stimulus duration failed to produce OKAN second-phase (OKAN-II) (upward slow-phase); however, with an increase in stimulus duration, the percentage appearance increased. There was no change in percentage appearance, regardless of the duration of upward stimulus. The asymmetry of OKAN-I and that of OKAN-II differed to a certain degree.

Animals↗