Sleep deprivation biases the neural mechanisms underlying economic preferences.

A single night of sleep deprivation (SD) evoked a strategy shift during risky decision making such that healthy human volunteers moved from defending against losses to seeking increased gains. This change in economic preferences was correlated with the magnitude of an SD-driven increase in ventromedial prefrontal activation as well as by an SD-driven decrease in anterior insula activation during decision making. Analogous changes were observed during receipt of reward outcomes: elevated activation to gains in ventromedial prefrontal cortex and ventral striatum, but attenuated anterior insula activation following losses.

Sleep deprivation and interference by emotional distracters.

Study Objectives: We determined if sleep deprivation would amplify the effect of negative emotional distracters on working memory.

Design: A crossover design involving 2 functional neuroimaging scans conducted at least one week apart. One scan followed a normal night of sleep and the other followed 24 h of sleep deprivation.

Hippocampal region-specific contributions to memory performance in normal elderly.

To investigate the relationship between regional hippocampal volume and memory in healthy elderly, 147 community-based volunteers, aged 55-83years, were evaluated using magnetic resonance imaging, the Groton Maze Learning Test, Visual Reproduction and the Rey Auditory Verbal Learning Test. Hippocampal volumes were determined by interactive volumetry. We found greater age-related reduction in the volume of the hippocampal head relative to the tail.

Donepezil improves episodic memory in young individuals vulnerable to the effects of sleep deprivation.

Study Objectives: We investigated if donepezil, a long-acting orally administered cholinesterase inhibitor, would reduce episodic memory deficits associated with 24 h of sleep deprivation.

Design: Double-blind, placebo-controlled, crossover study involving 7 laboratory visits over 2 months. Participants underwent 4 functional MRI scans; 2 sessions (donepezil or placebo) followed a normal night's sleep, and 2 sessions followed a night of sleep deprivation.

Cognitive function and brain structure correlations in healthy elderly East Asians.

We investigated the effect of age and health variables known to modulate cognitive aging on several measures of cognitive performance and brain volume in a cohort of healthy, non-demented persons of Chinese descent aged between 55 and 86 years. 248 subjects contributed combined neuropsychological, MR imaging, health and socio-demographic information. Speed of processing showed the largest age-related decline.

Cholinergic augmentation modulates visual task performance in sleep-deprived young adults.

Using 24 h of total sleep deprivation to perturb normal cognitive function, we conducted a double-blind, placebo-controlled crossover study to evaluate the effect of the acetylcholinesterase inhibitor, donepezil, on behavioral performance and task-related brain activation in 28 healthy, young, adult volunteers. The behavioral tasks involved the parametric manipulation of visual short-term memory load and perceptual load in separate experiments indirectly evaluating attention. Sleep deprivation significantly reduced posterior cortical activation (intraparietal sulcus and extrastriate cortex) at all levels of visual memory as well as perceptual load.

Functional neuroimaging of sleep deprived healthy volunteers and persons with sleep disorders: a brief review.

Sleep loss can severely impact on the integrity of cognitive functions. This review highlights the recent functional neuroimaging studies on the brain's response while performing cognitive tasks when deprived of sleep. Among sleep-deprived healthy volunteers, reduced attention, accompanied by lowered parieto-occipital activation, may underlie performance decrements seen in other "higher cognitive domains".

Functional neuroimaging insights into how sleep and sleep deprivation affect memory and cognition.

Purpose Of Review: The review summarizes current knowledge about what fMRI has revealed regarding the neurobehavioral correlates of sleep deprivation and sleep-dependent memory consolidation.

Recent Findings: Functional imaging studies of sleep deprivation have characterized its effects on a number of cognitive domains, the best studied of these being working memory. There is a growing appreciation that it is important to consider interindividual differences in vulnerability to sleep deprivation, task and task difficulty when interpreting imaging results.

Functional imaging of working memory following normal sleep and after 24 and 35 h of sleep deprivation: Correlations of fronto-parietal activation with performance.

Working memory was evaluated after normal sleep, and at 24 and 35 h of sleep deprivation (SD) in 26 healthy young adults to examine the neural correlates of inter-individual differences in performance. The extent of performance decline was not significantly different between the two SD test periods although there was greater variability in performance at SD35. In both SD sessions, there was reduced task-related activation (relative to normal sleep) in both superior parietal regions and the left thalamus.