Gray Matter Volume In Brain Areas Research Articles

Plasticity and Susceptibility of Brain Morphometry Alterations to Insufficient Sleep.

Background: Insufficient sleep is common in daily life and can lead to cognitive impairment. Sleep disturbance also exists in neuropsychiatric diseases. However, whether and how acute and chronic sleep loss affect brain morphology remain largely unknown.Methods: We used voxel-based morphology method to study the brain structural changes during sleep deprivation (SD) at six time points of rested wakefulness, 20, 24, 32, 36 h SD, and after one night sleep in 22 healthy subjects, and in 39 patients with chronic primary insomnia relative to 39 status-matched good sleepers. Attention network and spatial memory tests were performed at each SD time point in the SD Procedure. The longitudinal data were analyzed using one-way repeated measures ANOVA, and post-hoc analysis was used to determine the between-group differences.Results: Acute SD is associated with widespread gray matter volume (GMV) changes in the thalamus, cerebellum, insula and parietal cortex. Insomnia is associated with increased GMV in temporal cortex, insula and cerebellum. Acute SD is associated with brain atrophy and as SD hours prolong more areas show reduced GMV, and after one night sleep the brain atrophy is restored and replaced by increased GMV in brain areas. SD has accumulative negative effects on attention and working memory.Conclusions: Acute SD and insomnia exhibit distinct morphological changes of GMV. SD has accumulative negative effects on brain morphology and advanced cognitive function. The altered GMV may provide neurobiological basis for attention and memory impairments following sleep loss.Statement of significanceSleep is less frequently studied using imaging techniques than neurological and psychiatric disorders. Whether and how acute and chronic sleep loss affect brain morphology remain largely unknown. We used voxel-based morphology method to study brain structural changes in healthy subjects over multiple time points during sleep deprivation (SD) status and in patients with chronic insomnia. We found that prolonged acute SD together with one night sleep recovery exhibits accumulative atrophic effect and recovering plasticity on brain morphology, in line with behavioral changes on attentional tasks. Furthermore, acute SD and chronic insomnia exhibit distinct morphological changes of gray matter volume (GMV) but they also share overlapping GMV changes. The altered GMV may provide structural basis for attention and memory impairments following sleep loss.

Complexes of beta-amyloid peptides and of intracellular proteins in cerebrospinal fluid: New biomarkers of Alzheimer's disease?

Background: Insulin resistance, as seen in type 2 diabetes, has been shown to increase the risk of late onset Alzheimer’s Disease (AD) by as much as two-fold. In AD patients, characteristic findings are seen with structural magnetic resonance imaging (MRI) including global atrophy as well as regional reductions in gray matter volume (GMV) in the hippocampus, precuneus, posterior cingulate gyrus, parietotemporal, prefrontal, and orbitofrontal cortices. Additionally, negative correlations between peripheral insulin levels and regional GMV are seen in insulin resistant subjects in the middle temporal gyrus.The current study investigated whether elevated fasting glucose (FSG) levels were associated with lower GMV in brain areas that have been preferentially affected by AD. This association difference was further investigated between carrier and non-carrier (NC) groups of the apolipoprotein E (APOE) e4 allele, a genetic risk factor for late onset AD. Methods: Statistical Parametric Mapping (SPM), an automated brain imaging analysis computer package, was used to spatially normalize individual brains to a standard brain template, to obtain GMV maps from structural MRI, and to examine the correlations between higher FSG levels and lower structural MRI GMV measurements in 118 cognitively normal, non-diabetic individuals 6466 years of age (59e4 carriers and 59 NCs). A significance threshold of p 1⁄4 .005 was set for all imaging related analyses. Results: As predicted, significant correlations were seen between higher levels of FSG and lower GMV in AD-affected regions including the left inferior orbitofrontal cortex, parietal, and occipital lobes and the left and right frontal and temporal lobes. Negative correlations between FSG and regional GMV in the middle temporal gyri confirmed findings seen in insulin resistant subjects. Additionally, these associations in AD-related areas are seen in both carriers and NC. Conclusions: Higher FSG levels in cognitively normal, non-diabetic, older adults are associated with lower GMV in AD related brain areas, confirming that elevated FSG may be associated with AD risk, independent of APOEe4 status. Lastly, this study encourages the consideration of elevated FSG and other indicators of glucose control as targets for AD prevention trials, complementing the findings previously established with fluorodeoxyglucose positron emission tomography neuroimaging.