***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background Elucidating the neurobiological effects of sleep and waking remains an important goal of the neurosciences . Recently , animal studies indicated that sleep is important for cell membrane and myelin maintenance in the brain and that these structures are particularly susceptible to insufficient sleep . Here , we tested the hypothesis that a day of waking and sleep deprivation would be associated with changes in diffusion tensor imaging ( DTI ) indices of white matter microstructure sensitive to axonal membrane and myelin alterations . Methods Twenty-one healthy adult males underwent DTI in the morning [ 7:30AM ; time point (TP)1 ] , after 14 hours of waking ( TP2 ) , and then after another 9 hours of waking ( TP3 ) . Whole brain voxel-wise analysis was performed with tract based spatial statistics . Results A day of waking was associated with widespread increases in white matter fractional anisotropy , which were mainly driven by radial diffusivity reductions , and sleep deprivation was associated with widespread fractional anisotropy decreases , which were mainly explained by reductions in axial diffusivity . In addition , larger decreases in axial diffusivity after sleep deprivation were associated with greater sleepiness . All DTI changes remained significant after adjusting for hydration measures . Conclusions This is the first DTI study of sleep deprivation in humans . Although previous studies have observed localized changes in DTI indices of cerebral microstructure over the course of a few hours , further studies are needed to confirm widespread DTI changes within hours of waking and to clarify whether such changes in white matter microstructure serve as neurobiological substrates of sleepiness Diffusion-weighted MRI ( DW-MRI ) has become a popular imaging modality for probing the microstructural properties of white matter and comparing them between population s in vivo . However , the contrast in DW-MRI arises from the microscopic r and om motion of water molecules in brain tissues , which makes it particularly sensitive to macroscopic head motion . Although this has been known since the introduction of DW-MRI , most studies that use this modality for group comparisons do not report measures of head motion for each group and rely on registration -based correction methods that can not eliminate the full effects of head motion on the DW-MRI contrast . In this work we use data from children with autism and typically developing children to investigate the effects of head motion on differences in anisotropy and diffusivity measures between groups . We show that group differences in head motion can induce group differences in DW-MRI measures , and that this is the case even when comparing groups that include control subjects only , where no anisotropy or diffusivity differences are expected . We also show that such effects can be more prominent in some white-matter pathways than others , and that they can be ameliorated by including motion as a nuisance regressor in the analyses . Our results demonstrate the importance of taking head motion into account in any population study where one group might exhibit more head motion than the other Few studies have used diffusion tensor imaging ( DTI ) to investigate the micro-structural alterations of WM in patients with restrictive eating disorders ( rED ) , and longitudinal data are lacking . Twelve patients with rED were scanned at diagnosis and after one year of family-based treatment , and compared to twenty-four healthy controls ( HCs ) through DTI analysis . A tract-based spatial statistics procedure was used to investigate diffusivity parameters : fractional anisotropy ( FA ) and mean , radial and axial diffusivities ( MD , RD and AD , respectively ) . Reduced FA and increased RD were found in patients at baseline in the corpus callosum , corona radiata and posterior thalamic radiation compared with controls . However , no differences were found between follow-up patients and controls , suggesting a partial normalization of the diffusivity parameters . In patients , trends for a negative correlation were found between the baseline FA of the right anterior corona radiata and the Eating Disorder Examination Question naire total score , while a positive trend was found between the baseline FA in the splenium of corpus callosum and the weight loss occurred between maximal documented weight and time of admission . A positive trend for correlation was also found between baseline FA in the right anterior corona radiata and the decrease in the Obsessive-Compulsive Inventory Revised total score over time . Our results suggest that the integrity of the limbic – thalamo – cortical projections and the reward-related circuitry are important for cognitive control processes and reward responsiveness in regulating eating behavior BACKGROUND Anorexia nervosa is characterized by extreme low body weight and alterations in affective processing . The subcallosal cingulate regulates affect through wide-spread white matter connections and is implicated in the pathophysiology of anorexia nervosa . OBJECTIVES We examined whether those with treatment refractory anorexia nervosa undergoing deep brain stimulation ( DBS ) of the subcallosal white matter ( SCC ) show : ( 1 ) altered anatomical SCC connectivity compared to healthy controls , ( 2 ) white matter microstructural changes , and ( 3 ) microstructural changes associated with clinical ly-measured affect . METHODS Diffusion magnetic resonance imaging ( dMRI ) and deterministic multi-tensor tractography were used to compare anatomical connectivity and microstructure in SCC-associated white matter tracts . Eight women with treatment-refractory anorexia nervosa were compared to 8 age- and sex-matched healthy controls . Anorexia nervosa patients also completed affect-related clinical assessment s presurgically and 12 months post-surgery . RESULTS ( 1 ) Higher ( e.g. , left parieto-occipital cortices ) and lower ( e.g. , thalamus ) connectivity in those with anorexia nervosa compared to controls . ( 2 ) Decreases in fractional anisotropy , and alterations in axial and radial diffusivities , in the left fornix crus , anterior limb of the internal capsule ( ALIC ) , right anterior cingulum and left inferior fronto-occipital fasciculus . ( 3 ) Correlations between dMRI metrics and clinical assessment s , such as low pre-surgical left fornix and right ALIC fractional anisotropy being related to post-DBS improvements in quality -of-life and depressive symptoms , respectively . CONCLUSIONS We identified widely-distributed differences in SCC connectivity in anorexia nervosa patients consistent with heterogenous clinical disruptions , although these results should be considered with caution given the low number of subjects . Future studies should further explore the use of affect-related connectivity and behavioral assessment s to assist with DBS target selection and treatment outcome The objective was to examine whether cerebral volumes are reduced , and in what regions , in adolescents with anorexia nervosa and to study changes after nutritional recovery . Twelve anorexia nervosa ( DSM-IV ) patients aged 11 - 17 consecutively admitted to an Eating Disorders Unit were assessed by means of  psychopathological scales  , neuropsychological battery and voxel-based morphometric ( VBM ) magnetic resonance imaging at admission and after 7 months ' follow-up . Nine control subjects of similar age , gender and estimated intelligence level were also studied . The two groups showed differences in gray matter ( F=22.2 ; p<0.001 ) and cerebrospinal fluid ( CSF ) ( F=21.2 ; p<0.001 ) but not in white matter volumes . In anorexic patients , gray matter volume correlated negatively with the copy time from the Rey Complex Figure Test . In the regional VBM study several temporal and parietal gray matter regions were reduced . During follow-up there was a greater global increase in gray matter ( F=10.7 ; p=0.004 ) and decrease in CSF ( F=22.1 ; p=0.001 ) in anorexic patients . The increase in gray matter correlated with a decrease in cortisol ( Spearman correlation=-0.73 ; p=0.017 ) . At follow-up there were no differences in global gray matter ( F=2.1 ; p=0.165 ) , white matter ( F=0.02 , p=0.965 ) or CSF ( F=1.8 ; p=0.113 ) volumes between both groups . There were still some smaller areas , in the right temporal and both supplementary motor area , showing differences between them in the regional VBM study . In conclusion , in adolescent anorexic patients  gray matter is more affected than white matter and mainly involves the posterior regions of the brain . Overall gray matter alterations are reversible after nutritional recovery 
    Output:
    
It was less clear whether white matter alterations persist after recovery from anorexia nervosa .
Conclusion White matter microstructure appears to be affected in anorexia nervosa , and these alterations may play a role in the pathophysiology of this eating disorder .
Although we found white matter alterations in bulimia nervosa that were similar to those in anorexia nervosa , white matter changes in bulimia nervosa remain poorly investigated , and these findings were less conclusive .