Effects of sleep deprivation on cognitive performance

It has been estimated that over 20% of adults suffer from some form of sleep deprivation.Insomnia and sleep deprivation are common symptoms of depression and can be an indication of other mental disorders. The consequences of not getting enough sleep could have dire results; not only to the health of the individual, but those around them as sleep deprivation increases the risk of human-error related accidents, especially with vigilance-based tasks involving technology.

The parietal lobes of the brain are largely involved in attention. Lesions to this region of the brain in humans result in difficulty or inability to attend to events that are contralateral to the lesioned hemisphere. Those with lesions to the posterior parietal lobe have little to no difficulty shifting attention to and from stimuli appearing in the space ipsilateral to the lesioned hemisphere. However, they do display a slowed response in shifting their focus of current attention to events and stimuli appearing contralateral to the lesioned hemisphere.

Studies involving single-unit recordings from the parietal lobes of monkeys have indicated that there are neurons solely involved in integrating visual spatial information with postural information. Without this apparent combining of spatial information, it would be difficult or impossible to locate objects in external space, as information provided solely by the retina is insufficient. The position of the eyes, head and body must also be taken into consideration.

In addition, studies involving transcranial magnetic stimulation application over the parietal lobes as well as positron emission tomography (PET) analysis of the parietal lobes suggest that this region is involved in conjunction searches, but not in single-feature searches. (See Visual search for supplementary information.)

...
Wikipedia