Poster No:
1761
Submission Type:
Late-Breaking Abstract Submission
Authors:
Maggie Baird1, Marc Seal2, Richard Beare2, Jacqueline Anderson3, Joseph Yang4
Institutions:
1The University of Melbourne, Melbourne, Victoria, 2Murdoch Children's Research Institute, Melbourne, VIC, 3The University of Melbourne, Melbourne, VIC, 4Neuroscience Advanced Clinical Imaging Service (NACIS), Melbourne, Australia
First Author:
Maggie Baird
The University of Melbourne
Melbourne, Victoria
Co-Author(s):
Marc Seal
Murdoch Children's Research Institute
Melbourne, VIC
Richard Beare
Murdoch Children's Research Institute
Melbourne, VIC
Joseph Yang
Neuroscience Advanced Clinical Imaging Service (NACIS)
Melbourne, Australia
Late Breaking Reviewer(s):
Jean Chen
Rotman Research Institute, Baycrest
Toronto, Ontario
Rosanna Olsen
Rotman Research Institute, Baycrest Academy for Research and Education
Toronto, Ontario
Introduction:
Evidence points to the vulnerability of the thalamus in mild traumatic brain injury (mTBI), due to its anatomical position at the brains' centre of mass and abundant cortical connectivity profile. Our previous work has shown increased volume in the bilateral medial and right intralaminar thalamus (Baird et al., 2024). Here, we extend this work within the same cohort of participants by investigating the structural connectivity profiles of thalamic subnuclei.
Methods:
39 mTBI patients and 29 trauma control (TC) patients aged 18 – 60 were recruited as inpatients in Melbourne, Australia. Participants were classified into the mTBI group if they fulfilled the World Health Organisation criteria for definition of mTBI, and into the TC group if they sustained a traumatic injury in the absence of a head strike. Participants completed an MRI neuroimaging protocol including both sMRI (MPRAGE) and multishell dMRI sequences at 6 – 10 weeks (m = 57 days, sd = 11) following injury. Lateralised thalamic segmentations were derived using a Bayesian joint sMRI and dMRI algorithm, and subnuclei were summed to create 6 subregions. Nodes of the structural connectivity network were defined using a custom parcellation scheme created by combining thalamic subregions with Destrieux parcellations, yielding 179 regions of interest in total. Structural connectome reconstruction was performed using the recommended pipeline for multi-shell, multi-tissue constrained spherical deconvolution. Structural connectivity matrices were generated by mapping streamline reconstruction onto the 179 parcels, and adjacency matrices were subsequently thresholded using consistency-based thresholding. The weight of the connections between nodes (nodal strength) was calculated. A series of Bayesian linear models were fitted, with age and sex as covariates.
Results:
Results from the Bayesian linear models provided evidence of no group difference in strength for 7 of 12 thalamic subregions (BF10 <1/3), and inconclusive evidence for or against the null hypothesis in 4 thalamic subregions (BF10 1/3 – 1). There was anecdotal evidence to support decreased left lateral (dorsal tier) strength in the mTBI group compared to TCs (BF10 = 1.430).
Conclusions:
These findings show that at approximately 2-months following an mTBI event, thalamic nodal strength is normal, aside from anecdotal evidence suggesting decreased left lateral (dorsal tier) strength in the mTBI group. This suggests that while this cohort show increased thalamic subregion grey matter volume, this structural abnormality does not relate to changes in connectivity strength at the macroscopic level. Future work should complement these collective findings by investigating the microstructural features of thalamic white matter tracts.
Neuroanatomy, Physiology, Metabolism and Neurotransmission:
Subcortical Structures 1
White Matter Anatomy, Fiber Pathways and Connectivity 2
Keywords:
Thalamus
Tractography
White Matter
Other - Concussion
1|2Indicates the priority used for review
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Healthy subjects only or patients (note that patient studies may also involve healthy subjects):
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Was this research conducted in the United States?
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Were any human subjects research approved by the relevant Institutional Review Board or ethics panel?
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Were any animal research approved by the relevant IACUC or other animal research panel?
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Please indicate which methods were used in your research:
Structural MRI
Diffusion MRI
For human MRI, what field strength scanner do you use?
3.0T
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FSL
Free Surfer
Provide references using APA citation style.
Baird, M. E., Beare, R., Seal, M. L., Yang, J. Y. M., & Anderson, J. F. (2024). Mild traumatic brain injury is associated with increased thalamic subregion volume in the subacute period following injury. Journal of Neuroscience Research, 102(12).
No