Biology subjects

Rasmussen, J. M.

Publications and source records attributed to Rasmussen, J. M..

3 recordsLinked to original sources

bioRxiv2025

MRI-Based Structural Development of the Human Newborn Hypothalamus

BackgroundPreclinical evidence suggests that intrauterine exposures can impact hypothalamic structure at birth and future disease risk, yet early human data are limited. MethodsHypothalamic volumes were measured from 699 T1-weighted MRI scans from 631 newborns (54% female; 27-45 weeks postmenstrual age/PMA) in the Developing Human Connectome Project. Linear mixed-effects models tested associations with prenatal exposures: gestational age (GA) at birth, PMA at scan, sex, maternal body mass index (BMI), and smoking. Findings were partially replicated in the Adolescent Brain and Child Development (ABCD) Study (release 5.1) data (16,934 observations from 11,207 participants). ResultsAbsolute hypothalamus volume increased with PMA (+5.5%/week, t=39.9, p<10-{superscript 1}), but not after adjusting for brain volume (t=1.2, p=0.24). Males showed larger absolute (+3.3%, t=3.2, p=0.002) but smaller relative hypothalamus volume (t=-2.8, p=0.005). Lower GA was linked to larger relative hypothalamus volume (t=-6.5, p<10-), with evidence for sex moderation (t=-2.4, p=0.019). Smoking during pregnancy was associated with smaller hypothalamus volume in newborns (t=-2.05, p=0.04; dose dependence: t=-2.9, p<0.01). Smoking remained associated with reduced hypothalamus volume in adolescents (t=-2.8, p=0.005). ConclusionsThe findings suggest that the hypothalamus is a crucial and underexplored target of perinatal influences for understanding the origins of long-term health and disease. Impact- This study highlights the hypothalamus as a critical and underexplored target for understanding how prenatal exposures in human newborns could influence long-term health and disease. - Gestational age (GA) at birth, postmenstrual age at scan, and smoking during pregnancy are associated with hypothalamic volume in newborns. - The effects of GA on adjusted hypothalamic volume appear to be transient, while the effects of smoking seem to last throughout adolescence. - Our findings suggested sex-specific effects on the associations between volume and age measures across development.

neuroscience↗

bioRxiv2025

A combined neuroanatomy, ex vivo imaging and immunohistochemistry defined MRI mask for the human paraventricular nucleus of the thalamus

The paraventricular nucleus of the thalamus (PVT) is an evolutionarily conserved midline thalamic structure known to contribute to arousal, interoceptive states, and motivated behaviors. Yet, a consensus anatomical definition of the human PVT across tissue-based and MRI-based approaches remains elusive, thereby limiting reliable translation between its cellular characteristics and in vivo functional connectivity. To address this challenge, we describe a histologically-informed PVT segmentation compatible with standard 3T MR imaging pipelines. We performed postmortem anatomical MRI scans on an intact whole brain and an excised thalamic block, manually segmented the PVT at high resolution using ex vivo calretinin staining and neuroanatomical landmarks, registered the resulting image-label pair to a commonly used MRI template space (Montreal Neurological Institutes MNI152), and performed a comparative reanalysis using this newly defined mask. This tissue-grounded PVT mask largely overlaps spatially with existing MRI-based PVT masks, with the exception of additional voxels posteriorly. Importantly, the functional connectivity patterns of this tissue-grounded mask are highly consistent with those previously reported. Collectively, this multimodal definition of the human PVT balances tissue-based ground truth with in vivo MRI features, providing a valuable resource for advancing translation between cellular level features identified by histology and in vivo functional connectivity at the meso/macro scale in the understudied human PVT. Key PointsO_LIAddresses conflict between histological and MRI-based borders of the human PVT. C_LIO_LIHistologically-defined PVT boundaries indicate additional posterior tail to the human PVT as compared to existing human MRI atlases. C_LIO_LIProvided MRI mask demonstrates functional connectivity patterns consistent with prior human and rodent studies. C_LI

neuroscience↗

bioRxiv2023

Associations between maternal pre-pregnancy BMI and infant striatal mean diffusivity

Background/ObjectivesIt is well-established that parental obesity is a strong risk factor for associates with offspring obesity. Further, a converging body of evidence now suggests that maternal weight profiles may affect the developing offspring brain in a manner that confers future obesity risk. Here, we investigated how pre-pregnancy maternal weight status influences the reward-related striatal areas of the offspring brain during in utero development. MethodsWe used diffusion tensor imaging to quantify the microstructure of the striatal brain regions of interest in neonates (N = 116 mean gestational weeks at birth 39.88, SD = 1.14; and at scan 43.56, SD = 1.05). Linear regression was used to test the associations between maternal pre-pregnancy body mass index and infant striatal mean diffusivity. ResultsA strong positive association was found between the maternal pre-pregnancy body mass index and newborn left caudate nucleus mean diffusivity. Results remained unchanged after the adjustment for covariates. ConclusionsIn utero exposure to maternal adiposity might have a growth impairing impact on the mean diffusivity of infant left caudate nucleus. Considering the involvement of caudate nucleus in regulating eating behaviour and food-related reward processing later in life, this finding calls for further investigations to define the prognostic relevance of early life caudate development and weight trajectories of the offspring.

neuroscience↗