The variegation of human brain vulnerability to rare genetic disorders and convergence with behaviorally defined disorders

BACKGROUND: Diverse gene dosage disorders (GDDs) increase risk for psychiatric impairment, but characterization of GDD effects on the human brain has so far been piecemeal with few simultaneous analyses of multiple brain features across different GDDs. METHODS: Here, through multimodal neuroimaging of 3 aneuploidy syndromes [XXY (total n = 191, 92 controls), XYY (total n=81, 47 controls) , trisomy 21 (total n=69, 41 controls)], we systematically map the effects of supernumerary X, Y and chromosome 21 dosage across a breadth of 15 different macrostructural, microstructural, and functional imaging derived phenotypes (IDPs). RESULTS: We reveal considerable diversity in cortical changes across GDDs and IDPs. This variegation of IDP change underlines the limitations of studying GDD effects unimodally. Integration across all IDP change maps reveals highly distinct architectures of cortical change in each GDD along with partial coalescence onto a common spatial axis of cortical vulnerability that is evident in all three GDDs. This common axis shows strong alignment with shared cortical changes in behaviorally defined psychiatric disorders and is enriched for specific molecular and cellular signatures. CONCLUSION: Use of multimodal neuroimaging data in three aneuploidies indicates that different GDDs impose unique fingerprints of change in the human brain that differ widely depending on the imaging modality being considered. Embedded in this variegation is a spatial axis of shared multimodal change that aligns with shared brain changes across psychiatric disorders and therefore represents a major high-priority target for future translational research in neuroscience

Putative dendritic correlates of chronic traumatic encephalopathy: A preliminary quantitative Golgi exploration

Chronic traumatic encephalopathy (CTE) is a neurodegenerative disorder that is associated with repetitive head impacts. Neuropathologically, it is defined by the presence of perivascular hyperphosphorylated tau aggregates in cortical tissue (McKee et al., 2016, Acta Neuropathologica, 131, 75-86). Although many pathological and assumed clinical correlates of CTE have been well characterized, its effects on cortical dendritic arbors are still unknown. Here, we quantified dendrites and dendritic spines of supragranular pyramidal neurons in tissue from human frontal and occipital lobes, in 11 cases with (Mage = 79 ± 7 years) and 5 cases without (Mage = 76 ± 11 years) CTE. Tissue was stained with a modified rapid Golgi technique. Dendritic systems of 20 neurons per region in each brain (N = 640 neurons) were quantified using computer-assisted morphometry. One key finding was that CTE neurons exhibited increased variability and distributional changes across six of the eight dendritic system measures, presumably due to ongoing degeneration and compensatory reorganization of dendritic systems. However, despite heightened variation among CTE neurons, CTE cases exhibited lower mean values than Control cases in seven of the eight dendritic system measures. These dendritic alterations may represent a new pathological marker of CTE, and further examination of dendritic changes could contribute to both mechanistic and functional understandings of the disease