Please use this identifier to cite or link to this item: http://hdl.handle.net/1946/12001
Sleep is a behavioral state exhibited by nearly all species and widely considered to be instrumental in health and cognitive function. Yet, the function of sleep remains obscure and its particular effects on various physiological functions, behavior, neurogenesis and development remains to be determined. The aim of this study is to investigate how sleep deprivation affects learning and memory in the zebrafish (Danio rerio) but zebrafish has in recent years been shown to be an excellent animal model for behavioral neuroscience.
Material and methods:
24 Zebrafish of wild type (AB) were exposed to a conditioned avoidance task in which they were trained to avoid a mild electric stimulus associated with either red or green colored and equally large halves of the conditioning chamber. The fish were then divided in two groups recorded in either sleep-promoting environment with lights-off from 22:00 to 8:00 (naive group) or in wake-promoting environment with no lights-off period (light group). The morning after naive and light groups were re-introduced into the conditioning chamber for a retention test.
Time spent in safe half of the conditioning chamber was significantly longer after training compared to before training for both groups (p<0.005) but no significant difference was found in time spent in safe half for neither group in pre-training and post-sleep (p>0.05) nor post-training and post-sleep (p>0.05). No significant differences (p>0.05) were found between groups in any of the measurements for time spent in safe half of the conditioning chamber. Significant differences were neither found in average swimming velocity overnight nor sleep percentage (p>0.05) between the two groups.
These results suggest that this particular conditioning avoidance task does not contribute to long-term memory in the zebrafish and therefore the effects of sleep deprivation cannot be evaluated. The data also shows that sleep deprivation with light does not contribute to the same loss of sleep in the zebrafish as other research suggests. Therefore both the conditioning avoidance task and sleep deprivation should be revised and restructured.