The cerebellum is a large hindbrain structure that is increasingly recognized for its contribution to diverse domains of cognitive and affective processing in human health and disease. Although several of these domains are sex biased, our fundamental understanding of cerebellar sex differences-including their spatial distribution, potential biological determinants, and independence from brain volume variation-lags far behind that for the cerebrum. Here, we harness automated neuroimaging methods for cerebellar morphometrics in 417 individuals to (1) localize normative male-female differences in raw cerebellar volume, (2) compare these to sex chromosome effects estimated across five rare sex (X/Y) chromosome aneuploidy (SCA) syndromes, and (3) clarify brain size-independent effects of sex and SCA on cerebellar anatomy using a generalizable allometric approach that considers scaling relationships between regional cerebellar volume and brain volume in health. The integration of these approaches shows that (1) sex and SCA effects on raw cerebellar volume are large and distributed, but regionally heterogeneous, (2) human cerebellar volume scales with brain volume in a highly nonlinear and regionally heterogeneous fashion that departs from documented patterns of cerebellar scaling in phylogeny, and (3) cerebellar organization is modified in a brain size-independent manner by sex (relative expansion of total cerebellum, flocculus, and Crus II-lobule VIIIB volumes in males) and SCA (contraction of total cerebellar, lobule IV, and Crus I volumes with additional X-or Y-chromosomes; X-specific contraction of Crus II-lobule VIIIB). Our methods and results clarify the shifts in human cerebellar organization that accompany interwoven variations in sex, sex chromosome complement, and brain size.
Objective: The number of children and adolescents (hereafter referred to as ''children'') who have been prescribed secondgeneration antipsychotics (SGAs) has increased over the last decade, but little is known about monitoring practices in pediatric patients who are vulnerable to adverse effects. We examined factors associated with psychiatrists' self-reported monitoring of children who were prescribed SGAs. Methods: A survey was mailed to a national, randomly selected sample of 1600 child and adolescent psychiatrists from the American Medical Association mailing list. Using logistic regression, we tested whether psychiatrist characteristics, attitudes, and practice characteristics were associated with monitoring (baseline and/or periodic) the following: Patient history, height and weight, blood pressure, waist circumference, lipid and glucose levels, and electrocardiogram. Results: Among the analytic sample of 308, at least two thirds reported monitoring patient history, height and weight, blood pressure, and fasting plasma lipids and glucose; 23% reported monitoring waist circumference; and 12% reported conducting an electrocardiogram. More than one third stated that they routinely monitored thyroid levels and more than half reported monitoring complete blood count and electrolytes/blood urea nitrogen. Psychiatrists reporting that they were able to measure vital signs on site were more likely to measure height and weight. Those who reported feeling comfortable conducting a physical examination were more likely to measure blood pressure. Those answering that the risk of metabolic syndrome was low were less likely to measure blood pressure and waist circumference. Being board certified and able to measure vital signs on site were associated with more monitoring of glucose and lipid levels. Conversely, years in practice and feeling that patients were nonadherent with blood work were associated with less monitoring of glucose and lipid levels. Conclusions: In this sample, inconsistent monitoring patterns of children prescribed SGAs were found. Efforts to communicate guidelines' evidence base and improve office capacity to measure and track adverse effects are needed to increase appropriate adverse effect monitoring in children who have been prescribed SGAs.
Gyrification is a fundamental property of the human cortex that is increasingly studied by basic and clinical neuroscience. However, it remains unclear if and how the global architecture of cortical folding varies with 3 interwoven sources of anatomical variation: brain size, sex, and sex chromosome dosage (SCD). Here, for 375 individuals spanning 7 karyotype groups (XX, XY, XXX, XYY, XXY, XXYY, XXXXY), we use structural neuroimaging to measure a global sulcation index (SI, total sulcal/cortical hull area) and both determinants of sulcal area: total sulcal length and mean sulcal depth. We detail large and patterned effects of sex and SCD across all folding metrics, but show that these effects are in fact largely consistent with the normative scaling of cortical folding in health: larger human brains have disproportionately high SI due to a relative expansion of sulcal area versus hull area, which arises because disproportionate sulcal lengthening overcomes a lack of proportionate sulcal deepening. Accounting for these normative allometries reveals 1) brain size-independent sulcal lengthening in males versus females, and 2) insensitivity of overall folding architecture to SCD. Our methodology and findings provide a novel context for future studies of human cortical folding in health and disease.
BackgroundXYY syndrome is a sex chromosome aneuploidy that occurs in ~ 1/850 male births and is associated with increased risk for neurodevelopmental difficulties. However, the profile of neurodevelopmental impairments, including symptoms of autism spectrum disorder (ASD) in XYY remains poorly understood. This gap in knowledge has persisted in part due to lack of access to patient cohorts with dense and homogeneous phenotypic data.MethodsWe evaluated a single-center cohort of 64 individuals with XYY aged 5–25 years, using a standardized battery of cognitive and behavioral assessments spanning developmental milestones, IQ, adaptive behavior, academic achievement, behavioral problems, and gold-standard diagnostic instruments for ASD. Our goals were to (i) detail the neurodevelopmental profile of XYY with a focus on ASD diagnostic rates and symptom profiles, (ii) screen phenotypes for potential ascertainment bias effects by contrasting pre- vs. postnatally diagnosed XYY subgroups, and (iii) define major modules of phenotypic variation using graph-theoretical analysis.ResultsAlthough there was marked inter-individual variability, the average profile was characterized by some degree of developmental delay, and decreased IQ and adaptive behavior. Impairments were most pronounced for language and socio-communicative functioning. The rate of ASD was 14%, and these individuals exhibited autism symptom profiles resembling those observed in ASD without XYY. Most neurodevelopmental dimensions showed milder impairment among pre- vs. postnatally diagnosed individuals, with clinically meaningful differences in verbal IQ. Feature network analysis revealed three reliably separable modules comprising (i) cognition and academic achievement, (ii) broad domain psychopathology and adaptive behavior, and (iii) ASD-related features.ConclusionsBy adding granularity to our understanding of neurodevelopmental difficulties in XYY, these findings assist targeted clinical assessment of newly identified cases, motivate greater provision of specialized multidisciplinary support, and inform future efforts to integrate behavioral phenotypes in XYY with neurobiology.Trial registrationsClinicalTrials.gov NCT00001246, “89-M-0006: Brain Imaging of Childhood Onset Psychiatric Disorders, Endocrine Disorders and Healthy Controls.”
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