Presentation on theme: "Sleep Deprivation Effects on Memory and Anxiety in Mice Eyitemi Opuogen Department of Biology, York College of Pennsylvania Sleep is imperative for a person’s."— Presentation transcript:
Sleep Deprivation Effects on Memory and Anxiety in Mice Eyitemi Opuogen Department of Biology, York College of Pennsylvania Sleep is imperative for a person’s health and wellbeing, but millions of people never get enough sleep (Sleep Health). Lack of sleep can lead to metabolic disorders, immune dysfunctions and chronic disease (Scully 2013). Sleep has an abundance of functions, but its role in memories can be extremely important (Diekelmann and Born, 2010). Research shows that a single night of sleep deprivation can obstruct the normal link of learning capabilities. It also shows that learning improvement is dependent on the first night of sleep, and that later sleep cannot replace the first night requirement (Stickgold et al., 2000). Anxiety and memory go hand in hand and there are theories that suggest that anxiety happens when the information perceived by an animal and information already saved in memory becomes mismatched (Beuzen and Belzung, 1995). There is conflicting research that shows that the more anxious a subject is, the better they are able to memorize (Haynes & Gormly, 1977). INTRODUCTION METHODS Sleep Deprivation Each mouse was placed on a 3 cm rubber stopper platform inside a 30-gallon (114-liters) glass tank. Tank was filled with water up to 1 cm beneath the surface of the stopper. The mice were sleep deprived for a total of 24 hours. Barnes Maze The mice were placed in a small white chamber in the middle of the and after 10 seconds, the chamber was removed. The mice were given 3 minutes to find the hiding box. If the mice did not find the hiding box, it was placed the hole. Water Tank Stress Control Similar to the sleep-deprived group. The 6 mice were also placed in a tank with platforms and water surrounding except the platforms were 12 cm, which allowed sleep. The mice were kept in the tank for 24 hours. The Elevated Zero Maze (EZM) The mice explored the maze for 5 minutes while their behavior was recorded. The total amount of time spent on the outside arms was recorded along with the number of times the mouse entered the open arms. RESULTS No significant change was seen between the number of total errors in all 18 mice as individuals (Figure 1, p= 0.5775) but in comparing the 3 groups there was a difference in errors (p < 0.0001). In comparing the sleep-deprived group to both overall control and water tank stress control there was a significant difference in time to target hole. There showed no significant variation between overall times in all 18 mice (Figure 2, p = 0.5124) and between the 3 different groups (P = 0.5112). The EZM revealed there were no significant differences in the total amount of time the mice were on the open arms (Figure 3, p=0.4494). The maze also didn’t show any differences in number of entries onto the open arms of the maze (Figure 4, p=0.4095). HYPOTHESIS Sleep deprivation has no significant effect on learning, memory, and anxiety. QUESTIONS Does sleep have an effect on learning and memory ? Can lack of sleep cause a high level of anxiety? ACKNOWLEDGEMENTS I would like to thank Dr. Bradley Rehnberg for help and support throughout my research. I would also like to thank Dr. Bridgette Hagerty for her statistical help with my results, Joan Carpenter for all of her help during my experiment with supplies, Melonie Hayes and Murielle Ahawo for helping with care and testing of my mice, and the York College Biology Department for this opportunity. CONCLUSION Although the mice did show signs of learning, the main result of this study showed that sleep deprived mice did not show a significant difference in their ability to learn and memorize, and showed no significant change in anxiety levels due to lack of sleep. The results of this study are somewhat similar to results in other previous studies that showed a significant impairment of reference memory, but no effect on working memory. It suggests that the sleep-deprived animal is only able to hold newly learned memory for a short amount of time after sleep deprivation memory (Youngblood et al.,1997). Because the mice were subjected to the single platform technique, they were unable to move at all. It was proposed that because there is no movement in the mice, they use their time off of the platform to increase in activity (Van Hulzen and Coenen, 1981). This explains why in both the Barnes Maze and Elevated Zero Maze, the sleep-deprived mice were more active than the two other groups. Lack of significant data could also be due to the fact that 24 hours without sleep is not enough to affect memory or anxiety levels. In most other studies the mice were sleep deprived for up to 72 hours. 18 Female Mice Sleep Deprived n=6 Water Tank Stress Control n=6 Control n=6 Barnes Maze Elevated Zero Maze LITERATURE CITED Diekelmann, S. and Born, J. The memory function of sleep.Nat. Rev.Neurosci., 2010, 11: 114– 126. Beuzen, A., C. Belzung, C. (1995). Link between emotional memory and anxiety state: A study by principal component analysis. Physiol Behav, 58 (1995), pp. 111–118 Scully, T. (2013). Sleep. Nature, 497(7450), S1. doi:10.1038/497S1a Sleep Health. Available from: http://sleepfoundation.org/. Retrieved November 30, 2014 Stickgold, R., James, L., & Hobson,J.A. (2000). Visual discrimination learning requires sleep after training. Nature Neuroscience, 3, 1237 – 1238 Haynes, J., & Gormly, J. (1977). Anxiety and memory. Bulletin of the Psychonomic Society, 9(3), 191-192. Youngblood, B.D.,Zhou, J., Smagin, G.N., Ryan, D.H., Harris, R.B.. Sleep deprivation by the flower pot technique and spatial reference memory Physiol Behav, 61 (1997), pp. 249–256 Van Hulzen ZJM, Coenen AML (1981) Paradoxical sleep deprivation and locomotor activity in rats. Physiol Behav 27:741–744 Figure 1: Number of total times mice tried to enter wrong hole (n=6). On trial day 1 the mice were subjected to the maze twice. Each day after the first trial the mice were trained on the maze once. Trial 5 was one week after trial 4 to test for memory. Two-Way ANOVA test was used to analyze the data and are presented as mean ± SEM. Figure 2: Number of total amount of time it took the mice to get to the target hole (n=6). On trial day 1 the mice were subjected to the maze twice. Each day after the first trial the mice were trained on the maze once. Trial 5 was one week after trial 4 to test for memory. Two- Way ANOVA test was used to analyze the data and are presented as mean ± SEM. For mice that never entered the target hole, 180 seconds (3 minutes) were recorded as total time. Figure 3: Total time mice were on the open arms of the Zero Plus Maze (n=6). One-Way ANOVA test was used to analyze total time on open arms. Data are presented as mean ± SEM. Figure 4: Total number of times mice entered the open arms of Zero Plus Maze (n=6). One-Way ANOVA test was used to analyze total amount of times the mice entered the open arms. Data are presented as mean ± SEM.