الفهرس 
مستخلص الدراسةيوجد فقط 14 صفحة متاحة للعرض العام
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المستخلص
The current study aimed at examining the effect of nocturnal sleep deprivation (deep- light) on some cognitive functions of: declarative memory, Reaction time, and on the work of the brain during the process of retrieval for verbal task that has been learned, in a sample of 20 male students ,aged (13-19 years) , residents of the orphanage.
The researcher prepared lists of paired-associate words; To measure the retrieval of the declarative memory, and used a Reaction time task; to measure reaction time which include some cognitive processes include: attention and decision-making, and Single Photon Emission Computed Tomography (SPECT); to measure physiological activity that accompanies the process of retrieval.
The experimental design composed of four sleep statuses: A normal sleep, a Total sleep deprivation, a deep sleep deprivation, and a light sleep deprivation. The researcher has used Non-Parametric Statistics for the study.
The study found that there are statistically significant differences at the level of 0.01 for retrieval among the four statuses, in favor of normal sleep. The study also showed that there aren’t statistically significant differences in simple reaction time among sleep statuses. The results showed that there are statistically significant differences at the level of 0.005 at discrimination reaction time among sleep statuses, in favor of normal sleep, It showed , also , significant difference at the level of 0.0001 at multiple –choice reaction time among sleep statuses in favor of normal sleep. These results is evident that the more difficult the task, the more effect of sleep deprivation on task performance.
The study found differences in brain regions that are responsible for retrieval according to the type of sleep and the level of retrieval .The results showed, in the case of normal sleep, that Temporal Lobes - left and right - showed high activity during retrieval of verbal information. In cases of sleep deprivation, the results indicated the presence of high activity in the frontal and Parietal lobes - left and right - in the case of high retrieval, while these same areas showed low activity in the case of low retrieval, and the Temporal lobes didn’t show remarkable activity in the three statuses of deprivation, either performance is high or low, except in high performance in deprivation of light sleep. Better performance – also- associated with high activity in Thalamus.
This shows competence of temporal lobes on verbal information retrieval in the left and right sides in the case of normal sleep, but in cases of sleep deprivation frontal and parietal lobes -left and right – perform a compensatory process during retrieval to compensate lack of temporal lobe activity for individuals who have high intelligence . The association between better performance and the activity in Thalamus shows that Thalamus plays a critical role in the integration of sensory information which transfer to the cerebral cortex , that lead to recall of information.
The results also found that there were no statistically significant differences in brain activity between left and right sides of the brain in the four lobes, this shows the integration of the brain during retrieval of declarative memory.