bioRxiv Science⌕ Search

bioRxiv · 10.1101/2024.06.03.597265

Mild traumatic brain injury is associated with increased thalamic subregion volume in the subacute period following injury

Abstract

Structural vulnerability of the thalamus remains under investigated in mild traumatic brain injury (mTBI), and few studies have addressed its constituent nuclei using robust segmentation methods. This study aimed to investigate thalamic subnuclei volume in the subacute period following mTBI. Trauma control (TC) and mTBI patients aged 18 - 60 years old completed an MRI neuroimaging protocol including both high resolution structural (T1w) and diffusion weighted sequences at 6 - 11 weeks following injury (mean: 57 days; sd 11). Each thalamus was segmented into its constituent subnuclei, which were grouped into eight lateralised subregions. Volumes of the subregions were calculated. Neurite Orientation Dispersion and Density (NODDI) maps with parameters optimised for grey matter were computed for the same subregions. Group differences in subregion volumes and NODDI parameters were investigated using Bayesian linear modelling, with age, sex, and intracranial volume included as covariates. Comparisons of mTBI (n = 39) and TC (n = 28) groups revealed evidence of relatively increased grey matter volume in the mTBI group for the bilateral medial and right intralaminar subregions (BF10 > 3). Of the subregions which showed volume differences, there was no evidence for differences in NODDI metrics between groups. This study demonstrates that in the subacute period following mTBI, there is evidence of increased volume in specific thalamic subregions. Putative mechanisms underpinning the increased volume observed here are disordered remyelination, or myelin debris yet to be cleared. Significance statementDespite the prevalence of continued cognitive, somatic, and vestibular symptoms in the subacute period (6 - 12 weeks) following an mTBI, a clear neuropathophysiological profile is yet to be determined. One key vulnerable structure in mTBI could be the thalamus, a subcortical grey matter structure which comprises numerous subregions. The present study investigated whether changes in thalamic subregion volume are evident in the subacute period. For the first time, we show that at approximately 8 weeks following injury, mTBI is associated with increased volume in specific thalamus subregions. This provides an important avenue for continued investigation into the clinical significance of these findings.

Source connections

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Baird, M. E., Beare, R. E., Seal, M. L., Yang, J. Y.-M., Anderson, J. F.. 2024-06-04. Mild traumatic brain injury is associated with increased thalamic subregion volume in the subacute period following injury. https://doi.org/10.1101/2024.06.03.597265

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

Rab10 and Arhgef7 interact to promote axon extension by linking vesicle supply and exocytosis

The formation of functional neural circuits begins with the extension of a single axon by immature neurons. Axon elongation requires an expansion of the plasma membrane that depends on the polarization of vesicle trafficking and exocytosis. It is not completely understood how the increased transport of vesicles into the growing axon is linked to their subsequent insertion into the plasma membrane. An analysis of early stages of neuronal differentiation indicates that an asymmetry in neurite length precedes axon specification and the accumulation of PPVs in the nascent axon. We show that increasing the transport of vesicles in unpolarized neurons is sufficient to promote the extension of additional axons. This effect indicates that an increased supply of vesicles stimulates their subsequent insertion into the membrane to allow neurite growth. The link between vesicle transport and exocytosis is mediated by the interaction of Rab10 with Arhgef7. Rab10 stimulates Arhgef7 activity on PPVs as a GEF for Cdc42b to promote axon extension through exocyst-dependent exocytosis, suggesting that their interaction links the increased supply of PPVs to their exocytosis.

neuroscience↗

Subcellular Spatial Profiling Unveils Links Between Neuritic Plaques with Selective Tau Vulnerability in Alzheimer's Disease

Alzheimer's disease (AD) features widespread extracellular amyloid-{beta} plaques but selective intraneuronal tau accumulation in cortical layers II/III and V, while layer IV remains relatively resistant. Here, we combined subcellular spatial transcriptomics with co-registered A{beta} and pTau immunohistochemistry to determine why neurons exposed to comparable plaque-associated pathology differ in somatic pTau accumulation. Plaque-associated neuritic stress occurred similarly across layers, but layer IV neurons showed attenuated pTau accumulation and reduced somatic expression of a shared neurite-soma stress program involving DCTN1, CALM3, NORAD, and PIN1. Trajectory analysis within layers identified tau-vulnerable and resistant neuronal states implicating calcium signaling, retrograde transport, and lysosomal function. Notably, astrocytic APOE-neuronal LRP1 co-expression increased significantly along the pTau-vulnerable trajectory, and APOE {epsilon}4 was associated with stronger coupling of local plaque pathology to pTau-associated molecular programs. These findings reveal neuronal programs and neuron-glia interactions underlying selective tau vulnerability and resistance in AD, highlighting potential tau-targeting therapeutics.

neuroscience↗

Widespread oscillatory suppression in autism persists in the absence of psychotropic medication.

Purpose: Investigate the neural oscillatory activity associated with autism spectrum disorder (ASD) using electroencephalographic (EEG) recordings in children and adolescents. Compare the corresponding oscillatory power between ASD patients taking psychotropic medication with a drug-naive group. Methods: ASD diagnosis was done using DSM-IV and CARS (Childhood Autism Rating Scale). EEG recordings employed 22 scalp electrodes (10/20 system). ASD vs. neurotypical groups were matched for sex and age (5 females; average age: ~10 years old). We analyzed the resting state (eyes open) EEG power spectrum during ~2-minute recordings. The multitaper FFT method was used to estimate spectral power for the delta, theta, alpha, beta and gamma frequency bands. We pooled together data from several electrodes to compute comprehensive power spectra and assess the oscillatory behavior of macro brain regions. Results: We observed widespread (~4Hz - 20Hz) oscillatory suppression comprising the theta, alpha and beta frequency bands. The most widespread and robust ASD-associated power suppression was in the high theta and alpha bands. Delta and gamma bands showed no significant power change for any of the brain regions studied. Results from a subgroup of patients (N = 9) who never used psychotropics confirmed these findings, indicating that they are not an artifact of medication. Conclusion: Suppression in theta, alpha and beta oscillations may offer insights into the neurophysiological underpinnings of autism and could be used as an accessible and comprehensive tool in ASD diagnosis, regardless of the patients being or not on medication.

neuroscience↗