Enhancement of Slow Wave Sleep after Learning Procedure Even in Immobilization Stress Condition

Abstract

Introduction: One of the important roles of sleep is memory consolidation which acquire by increasing REM and NREM sleep after learning procedure. Stress as a physiological and adaptive response to environmental stimuli could alter the sleep-wake cycle in humans and rodents.Here we examined the contribution of a model of immobilization stress on sleep and learning interplay.

Methods: Twenty-one male Wistar rats were designed in three groups, one exposed to immobilization in stony and uncomfortable place stress and the other entered to spatial learning protocol and in the third group the learning task was performed after stress con-dition. The SWS sleep was measure through EEG and EMG recording, 2 hours before and 2 hours after stress or learning condition or both of them for three consecutive days. The data was analyzed with semi-automatic sleep scoring method developed in MATLAB.

Results: The results indicated that immobilization stress could decrease the SWS sleep but the task performance with Barnes maze increase the SWS sleep as was anticipated. In the third group in spite of exposure to stress the learning procedure had its own effect and enhanced the SWS sleep.

Conclusion: This study indicated that although the immobilization stress decrease the SWS sleep in animals but learning protocols by enhancement of SWS sleep could over-come to the stress effect on SWS.

ACKNOWLEDGMENTS
We kindly acknowledge the guidance and advice from Professor Dr Sahraie the head of Neuroscience research center of Baqiyatallah University of Medical Sciences, and also thanks to financial support of Research Assistance office of faculty of medicine of Baqiyatallah University of Medical Sciences
CONFLICT OF INTEREST
There is no conflict of interest for the present study.
AUTHORS CONTRIBUTION
Mehdi Geraily Afra1,Collected the data.
Farideh Bahrami*, Supervised the research and wrote the paper.
Hedayat Sahraei, Advised and support the research.
Zahra Bahari, Statistically analyzed the data.
Ali Gharib, Analysed the sleep signals in MATLAB.
Hassan Ghoshooni, Edited the paper.
ETHICAL STATEMENT
this study were approved by bioethics committee of the animal house in Baqiyatallah University of Medical Science and have followed the NIH guidelines for use and care of Animals (Approval code: IR .bmsu.Rec1396.451).