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Date of Award

1-1978

Degree Type

Thesis

Degree Name

Doctor of Philosophy (PhD)

Department

Psychology

Supervisor

Dr. W. Heron

Abstract

It is known that human subjects deprived of meaningful visual, auditory and somatosensory stimulation (sensory deprivation), spend a larger portion of their time asleep (increased Stage I & II) than when in a normal environment. Furthermore, that phase of sleep which is characterized by the presence of rapid eye movements (REM sleep) is altered under these conditions, with REM density (number of rapid eye movements per minute) being greatly increased. However, little progress was being made toward understanding the conditions needed to obtain these effects, or the neural mechanism underlying them. Therefore, the effects of sensory deprivation on sleep of adult cat were studied, since if the results from the human experiments could be duplicated, various experimental, manipulations could be performed to elucidate the mechanisms.

It was found that adult cat responded to sensory deprivation in a manner analagous to human subjects since both REM density and the amount of time spent in the light phases of sleep increased during deprivation. The increase in REM density was not due to a change in the frequency with which the neural generator of REMs initiated eye movements since PGO wave density remained constant across conditions. Rather, it appeared to be due to the fact that the proportion of large amplitude, high velocity REMs increased during deprivation concomitantly with the change in REM density. In agreement with this, a positive correlation between REM density and average EOG amplitude was found under normal conditions and during sensory deprivation. The increase in sleep time during deprivation was found to be most similar to that described by others following sensory deafferentation. Thus, neither the proportion of deep SWS nor REM sleep was altered, while that of light SWS was greatly increased. The minimum condition needed to obtain these effects was found to be the lid suture procedure used to prevent vision during deprivation. Thus, lid suture alone and lid suture coupled with total light deprivation had equivalent effects while light deprivation alone caused only marginal changes. These results were contrasted to the human experiments where large sleep effects were obtained by requiring the subject to wear a translucent mask.

Finally, a preliminary account of the effects of sensory deprivation on other regulatory mechanisms was given. It was found that for some animals, food consumption and body weight increased and body core temperature decreased during deprivation.

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