Biology subjects

Howell, B. R.

Publications and source records attributed to Howell, B. R..

3 recordsLinked to original sources

bioRxiv2026

Microbes on the Mind: Multi-modal Neuroimaging Reveals Gut-Brain Axes in Infants

The gut microbiome develops from birth and is associated with cognition and mental health, but its relationship with early brain maturation remains unclear. We studied 223 typically developing infants aged 0-3 years using multimodal MRI and paired fecal shotgun metagenomics. Microbiome-wide association analysis linked microbial features to cortical morphology, white-matter microstructure, and functional networks. Regularized canonical correlation analysis identified structural-metabolic and functional-taxonomic covariance patterns. Sparse partial least-squares analysis recapitulated both full-sample CCA patterns and their defining structural and functional phenotypes, providing cross-method corroboration. Longitudinal canonical-score slopes did not significantly covary, whereas earlier neuroimaging CCA1 scores predicted microbiome CCA1 scores 1-6 months later in bidirectional autoregressive cross-lag models. These observational results identify coordinated developmental patterns and temporal ordering without establishing causality.

developmental biology↗

bioRxiv2024

Brain Charts for the Rhesus Macaque Lifespan

Recent efforts to chart human brain growth across the lifespan using large-scale MRI data have provided reference standards for human brain development. However, similar models for nonhuman primate (NHP) growth are lacking. The rhesus macaque, a widely used NHP in translational neuroscience due to its similarities in brain anatomy, phylogenetics, cognitive, and social behaviors to humans, serves as an ideal NHP model. This study aimed to create normative growth charts for brain structure across the macaque lifespan, enhancing our understanding of neurodevelopment and aging, and facilitating cross-species translational research. Leveraging data from the PRIMatE Data Exchange (PRIME-DE) and other sources, we aggregated 1,522 MRI scans from 1,024 rhesus macaques. We mapped non-linear developmental trajectories for global and regional brain structural changes in volume, cortical thickness, and surface area over the lifespan. Our findings provided normative charts with centile scores for macaque brain structures and revealed key developmental milestones from prenatal stages to aging, highlighting both species-specific and comparable brain maturation patterns between macaques and humans. The charts offer a valuable resource for future NHP studies, particularly those with small sample sizes. Furthermore, the interactive open resource (https://interspeciesmap.childmind.org) supports cross-species comparisons to advance translational neuroscience research.

neuroscience↗

bioRxiv2019

Molecular and Behavioral Effects of Infant Maltreatment across Generations in Rhesus Monkeys

Childhood maltreatment is among the most robust risk factors for subsequent psychiatric and medical disorders, and data in humans and rodents suggest that effects of adverse childhood experiences may be transmitted across generations. Recent indications for biological processes underlying this transfer of experiential effects are intriguing; yet, their relevance in primates is inconclusive due to limitations of current studies. In this study, we bridge research in rodent models and humans with a natural non-human primate model on intergenerational effects of childhood maltreatment. Using a unique, well-controlled, randomized cross-fostering design in rhesus monkeys, we test the influence of ancestral maltreatment on molecular, neuroendocrine and behavioral outcomes in offspring, and show that childhood maltreatment results in transmission of information to the subsequent generation independent of behavioral transmission. We further demonstrate differences in the offspring longitudinal DNA methylation profile of the FKBP5 gene, an important regulator of the hypothalamus-pituitary-adrenal axis in offspring of the maltreatment lineage compared to the control lineage. Finally, we show that differences in FKBP5 methylation have functional effects on molecular, neuroendocrine and behavioral outcomes in offspring of the maltreatment ancestral line, even if the infants were never exposed to maltreatment nor interacted with their exposed ancestors. Although the molecular mechanism underlying our observations remains unknown, our data point to a potential germline-dependent effect. In summary, our data suggest that history of maltreatment in primates can induce molecular and behavioral changes in a subsequent generation independent of behavioral transmission that may influence risk for mental and physical diseases across generations.

neuroscience↗