PubMed Health⌕ Search

Biomedical subjects

U Eyyunni

Publications and source records attributed to U Eyyunni.

4 recordsLinked to original sources
PubMedDate not supplied

Experimental motion sickness induced in squirrel monkeys by continuous off-axis horizontal rotation.

Under a variety of experimental conditions, nonrestrained adult male squirrel monkeys were subjected to continuous rotation in the horizontal plane at 33 rpm. Severity of motion-induced sickness was quantified by measuring latencies of three responses associated with sickness. Per- and postrotational nystagmus was recorded from a subsample of monkeys with permanent recording electrodes implanted in the bony orbits. Incidence of sickness depended on the time limits of stimulation imposed, and it occurred in a maximum of about 90 per cent of test sessions if rotation was continued for two hours. When subjected to ten once-per-day rotation sessions, only a few monkeys showed evidence of developing transient habituation of onset of motion sickness. Mean frequency of emetic episodes, however, declined over the latter half of the rotation series. Restricting visual cues by blindfolding the monkeys prevented most subjects from vomiting.

Animals↗
PubMedDate not supplied

Behavioral conditioning and experimental motion-induced sickness.

Adult male squirrel monkeys were the subjects of experiments conducted to determine whether or not repeated exposures to sickness-inducing horizontal rotation would result in behavioral conditioning of emetic responses. The development of conditioned food aversion and feeding suppression as a consequence of pre- and postrotation eating was quantified. It was concluded that neither instrumental conditioning nor classical conditioning were valid alternative hypotheses for the occurrence of repeated vomiting episodes over a period of ten daily exposures to motion. Conditioned aversion to fresh banana and feeding suppression developed gradually if rotation, which induced multiple bouts of vomiting, was sustained for 1- or 2-hour sessions. If spinning was terminated immediately after the first emetic response, no aversion or suppression emerged. The occurrence of food aversion, by itself, is questioned as a valid index of the presence of subjective concomitants of motion sickness in animals.

Animals↗