Year: 1969
Type: article
Abstract: A slow rotation room in a laboratory environment provides an excellent instrument for the study of motion sickness because the experimenter can control not only the stressful Coriolis accelerations, but also other important procedural and environmental variables.By exploiting this control, combined with the judicious selection of experimental subiects, i t was possible to confirm many previous findings and demonstrate that manifestations of disturbances i n the vestibular system fa1 I into two distinct categories.In the first category are reflex phenomena evoked by Coriolis accelerations when the head i s rotated out of the plane of the room's rotation, and revealed through systems which, under natural stimulus conditions, have functional articulations with vestibular receiving areas.Included here are a characteristic sensation of tumbling or rotation, the Coriolis oculogyral illusion, nystagmus, dizziness, and neuromuscular incoordination.The symptomatology i n the second category comprises an epiphenomenon superimposed on any manifestation of the first, when the unusual vestibular activity, presumably through facilitory-inhibitory processes, irradiates to cells or cel I assemblies not normally stimulated.These epiphenomena1 responses are absurd i n terms o f the needs of the organism, and there i s no evidence that their homeostatic mechanisms make any contribution toward restoring a homeostatic state in the vestibular system.The sites o f origin of these responses are not vestibular receiving areas under normal circumstances, and the Iinkage with the vestibular system must be facultative.The relations between manifestations i n the two categories suggest that the initial linkage, with certain sites a t least, may be neuronal, but that chemical stimuli must be implicated to account for 1) long latencies between stimulus and response, and 2) the long perseveration of the manifestations after the stressful accelerations have ceased.Selected experimental findings are used i n defining the characteristics of manifestations i n the two categories and i n demonstrating the nature of the facultative linkage between the otherwise independent systems underlying manifestations i n the two categories.It w i l l be shown that the experimenter, by manipulating mainly vestibular homeostatic mechanisms, can prevent the appearance of manifestations in the second category, control their severity when evoked, and lose control only when these symptoms are relatively severe or perseverate long after the stressful accelerations have ceased.Practical and theoretical implications are discussed, including the concept of "functional vestibular reserve." I I
Source: PubMed
Author: A Graybiel
Institution: Naval Aerospace Medical Institute
Language: English
Subfield: Neurology
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W1785120808