summary

         The ability of the brain to function following sleep deprivation appears to vary with the task at hand, and in some cases the brain attempts to compensate for the adverse effects caused by lack of sleep, according to a study published in the February 10 issue of Nature. A team of researchers from the UCSD School of Medicine and the Veterans Affairs Healthcare System, San Diego used functional magnetic resonance imaging (FMRI) technology to monitor activity in the brain of sleep-deprived subjects performing simple verbal learning tasks. The temporal lobe, a brain region involved in language processing, was activated during verbal learning in rested subjects but not in sleep deprived subjects. The parietal lobes, not actived in rested subjects during the verbal exersice, was more active when the subjects were deprived of sleep. Although subject's memory performance was less efficient with sleep deprivation, greater activity in the parietal region associated with better memory. This study and another study published by Gillin's team in the Disember 1999 NeuroReport indicate that the brain is extremely dinamic in its effort to function when deprived of sleep, though consequence for the subject is deminished ability to perform basic cognitive tasks. It is also apparent that the effect of sleep loss are different depending on the cognitive task the brain is asked to perform. In the earlier study, the team studied sleep-deprived subjects performing and arithmetic task involving subtraction. In the study, they observed that the brain region activated in rested subjects doing the arithmetic problems were not active in the sleep-deprived subjects. Not other region of the brain became activated when subjects performed arithmetic when sleep-deprived.