Functional neural alterations in acute sleep deprivation: An activation likelihood estimation meta-analysis

1. BackgroundAdequate sleep during night is recommended about 7-9 hours by National Sleep Foundation. In modern life, however, many individuals complain from neuropsychological conditions due to sleep deprivation (SD) including cognitive and emotional impairments such as attention, memory, decision-making, and emotion dysregulation, which is particularly an important issue in some occupations. In addition, it has beendemonstrated that SD is an important comorbid condition in neuropsychiatric disorders e.g. schizophrenia, Alzheimers disease and anxiety disorder. Recently, numerous neuroimaging studies have been performed to find neural correlates of SD. These studies found functional alterations in various brain regions and their findings are inconsistent. Thus, we applied Activation estimation likelihood (ALE) meta-analysis to identify potential convergent regional findings across previous neuroimaging studies in SD. 2. MethodFollowing the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, we used PubMed to retrieve the task/resting-state functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) studies in acute SD (22-48 hours). Stereotactic data from the included studies were extracted from 31 studies, and subsequently tested for convergence using the ALE method. Theidentified regions were defined as seeds for further task-based and resting-state functional connectivity (FC) analyses. In addition, behavioral decoding analyses of the identified areas have been conducted using the BrainMap database. All analyses have been corrected for multiple comparisons using the cluster level familywise error (P < 0.05).3. Results ALE analyses indicated decreased activity in the right intraparietal sulcus (IPS) due to SD, which is mainly related to cognitive function such as visual perception, memory and reasoning. Task-based FC analyses of the IPS demonstrated co-activation with the left superior parietal lobule, IPS, Left and right lateral occipital cortex, left fusiform gyrus, and bilateral thalamus. Resting-state FC analyses reveled coactivation of the IPSwith cerebellum, bilateral Broadmann area 44, and left middle orbital gyrus. Conjunction of task-based and resting-state FC analyses depicted connectivity of this region and left Broadmann area 44, left lateral occipital cortex, left fusiform gyrus.4. Conclusions Our findings pointed to consistent reduced activity within the right IPS in acute SD, which is the main hub ofthe frontoparietal network. The functional characterization of the IPS using the BrainMap database suggested associated dysfunction of visual perception, memory and reasoning. Assessment of task-based and restingstate co-activation patterns indicated a joint network comprising the IPS, left Broadmann area 44, left lateral occipital cortex, left fusiform gyrus.