Age-Related Subcortical Brain Morphology Changes Following Three Hours of Sleep Deprivation

Sleep deprivation (SD) disrupted subcortical regions involved in emotion and attention. However, the age-related changes on subcortical brain morphology in processing of emotion and attention following SD remains unclear. Eighty participants consisting of 43 young people and 37 old people were included in this study. The volumetric analysis and vertex-wise shape analysis were employed to assess age-dependent structural abnormalities after SD. By volumetric analysis, we found significant main effect of deprivation with local atrophy in right amygdala. Shape analysis also showed the significant main effect of age in all subcortical structures. Moreover, the significant correlations between volume changes of bilateral amygdala and left thalamus after SD and scales scores refer to emotion processing and attention were observed in old adults. These findings indicated that SD altered gray matter volume and surface morphology of subcortical regions in old adults and suggested disrupted subcortical regions were associated with emotion and attention in old adults.

A meta-analysis of deep brain structural shape and asymmetry abnormalities in 2,833 individuals with schizophrenia compared with 3,929 healthy volunteers via the ENIGMA Consortium

Schizophrenia is associated with widespread alterations in subcortical brain structure. While analytic methods have enabled more detailed morphometric characterization, findings are often equivocal. In this meta-analysis, we employed the harmonized ENIGMA shape analysis protocols to collaboratively investigate subcortical brain structure shape differences between individuals with schizophrenia and healthy control participants. The study analyzed data from 2,833 individuals with schizophrenia and 3,929 healthy control participants contributed by 21 worldwide research groups participating in the ENIGMA Schizophrenia Working Group. Harmonized shape analysis protocols were applied to each site's data independently for bilateral hippocampus, amygdala, caudate, accumbens, putamen, pallidum, and thalamus obtained from T1-weighted structural MRI scans. Mass univariate meta-analyses revealed more-concave-than-convex shape differences in the hippocampus, amygdala, accumbens, and thalamus in individuals with schizophrenia compared with control participants, more-convex-than-concave shape differences in the putamen and pallidum, and both concave and convex shape differences in the caudate. Patterns of exaggerated asymmetry were observed across the hippocampus, amygdala, and thalamus in individuals with schizophrenia compared to control participants, while diminished asymmetry encompassed ventral striatum and ventral and dorsal thalamus. Our analyses also revealed that higher chlorpromazine dose equivalents and increased positive symptom levels were associated with patterns of contiguous convex shape differences across multiple subcortical structures. Findings from our shape meta-analysis suggest that common neurobiological mechanisms may contribute to gray matter reduction across multiple subcortical regions, thus enhancing our understanding of the nature of network disorganization in schizophrenia.

Cannabis use in patients with early psychosis is associated with alterations in putamen and thalamic shape

Around half of patients with early psychosis have a history of cannabis use. We aimed to determine if there are neurobiological differences in these the subgroups of persons with psychosis with and without a history of cannabis use. We expected to see regional deflations in hippocampus as a neurotoxic effect and regional inflations in striatal regions implicated in addictive processes. Volumetric, T1w MRIs were acquired from people with a diagnosis psychosis with (PwP + C = 28) or without (PwP - C = 26) a history of cannabis use; and Controls with (C + C = 16) or without (C - C = 22) cannabis use. We undertook vertex-based shape analysis of the brainstem, amygdala, hippocampus, globus pallidus, nucleus accumbens, caudate, putamen, thalamus using FSL FIRST. Clusters were defined through Threshold Free Cluster Enhancement and Family Wise Error was set at p < .05. We adjusted analyses for age, sex, tobacco and alcohol use. The putamen (bilaterally) and the right thalamus showed regional enlargement in PwP + C versus PwP - C. There were no areas of regional deflation. There were no significant differences between C + C and C - C. Cannabis use in participants with psychosis is associated with morphological alterations in subcortical structures. Putamen and thalamic enlargement may be related to compulsivity in patients with a history of cannabis use.

APPROXIMATING PRINCIPAL GENETIC COMPONENTS OF SUBCORTICAL SHAPE

Optimal representations of the genetic structure underlying complex neuroimaging phenotypes lie at the heart of our quest to discover the genetic code of the brain. Here, we suggest a strategy for achieving such a representation by decomposing the genetic covariance matrix of complex phenotypes into maximally heritable and genetically independent components. We show that such a representation can be approximated well with eigenvectors of the genetic covariance based on a large family study. Using 520 twin pairs from the QTIM dataset, we estimate 500 principal genetic components of 54,000 vertex-wise shape features representing fourteen subcortical regions. We show that our features maintain their desired properties in practice. Further, the genetic components are found to be significantly associated with the CLU and PICALM genes in an unrelated Alzheimer's Disease (AD) dataset. The same genes are not significantly associated with other volume and shape measures in this dataset.

Modulative effects of COMT haplotype on age-related associations with brain morphology

Catechol-O-methyltransferase (COMT), located on chromosome 22q11.2, encodes an enzyme critical for dopamine flux in the prefrontal cortex. Genetic variants of COMT have been suggested to functionally manipulate prefrontal morphology and function in healthy adults. This study aims to investigate modulative roles of individuals COMT SNPs (rs737865, val158met, rs165599) and its haplotypes in age-related brain morphology using an Asian sample with 174 adults aged from 21 to 80 years. We showed an age-related decline in cortical thickness of the dorsal visual pathway, including the left dorsolateral prefrontal cortex, bilateral angular gyrus, right superior frontal cortex, and age-related shape compression in the basal ganglia as a function of the genotypes of the individual COMT SNPs, especially COMT val158met. Using haplotype trend regression analysis, COMT haplotype probabilities were estimated and further revealed an age-related decline in cortical thickness in the default mode network (DMN), including the posterior cingulate, precuneus, supramarginal and paracentral cortex, and the ventral visual system, including the occipital cortex and left inferior temporal cortex, as a function of the COMT haplotype. Our results provided new evidence on an antagonistic pleiotropic effect in COMT, suggesting that genetically programmed neural benefits in early life may have a potential bearing towards neural susceptibility in later life. Hum Brain Mapp 37:2068-2082, 2016. © 2016 Wiley Periodicals, Inc.

Subcortical regional morphology correlates with fluid and spatial intelligence

Neuroimaging studies have revealed associations between intelligence and brain morphology. However, researchers have focused primarily on the anatomical features of the cerebral cortex, whereas subcortical structures, such as the basal ganglia (BG), have often been neglected despite extensive functional evidence on their relation with higher-order cognition. Here we performed shape analyses to understand how individual differences in BG local morphology account for variability in cognitive performance. Structural MRI was acquired in 104 young adults (45 men, 59 women, mean age = 19.83, SD = 1.64), and the outer surface of striatal structures (caudate, nucleus accumbens, and putamen), globus pallidus, and thalamus was estimated for each subject and hemisphere. Further, nine cognitive tests were used to measure fluid (Gf), crystallized (Gc), and spatial intelligence (Gv). Latent scores for these factors were computed by means of confirmatory factor analysis and regressed vertex-wise against subcortical shape (local displacements of vertex position), controlling for age, sex, and adjusted for brain size. Significant results (FDR < 5%) were found for Gf and Gv, but not Gc, for the right striatal structures and thalamus. The main results show a relative enlargement of the rostral putamen, which is functionally connected to the right dorsolateral prefrontal cortex and other intelligence-related prefrontal areas.