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Updated: Jul 8, 2026
Advanced Diffusion Imaging in The Hippocampus of Rats with Mild Traumatic Brain Injury
Published on: August 14, 2019
Early postnatal development of rat brain: in vivo diffusion tensor imaging
K H Bockhorst1, P A Narayana, R Liu
1University of Texas at Houston, Houston, Texas 77030, USA.
Insights
This study tracked brain development in rats using diffusion tensor imaging (DTI). It reveals how white matter structures mature, providing a baseline for understanding injury effects on neurodevelopment.
Area of Science:
- Neuroscience
- Developmental Biology
- Medical Imaging
Background:
- Perinatal hypoxia causes neurodevelopmental deficits, impacting neuronal migration.
- Understanding normal brain development is crucial before studying injury effects.
Purpose of the Study:
- To establish normal developmental trajectories of brain structures in Wistar rats.
- To characterize changes in diffusion tensor imaging (DTI) metrics during early brain development.
Main Methods:
- Longitudinal in vivo diffusion tensor imaging (DTI) from postnatal day 0 to 56.
- Analysis of DTI metrics (MD, FA, axial/radial diffusivity) in gray and white matter structures.
- Correlation of DTI changes with known developmental processes like myelination.
Main Results:
- Fractional anisotropy (FA) in the cortical plate and corpus callosum decreased initially, then increased in the corpus callosum.
- Gray matter structures showed minimal DTI metric changes, while white matter structures exhibited significant temporal alterations.
- Specific diffusivity changes (lambdat, lambdal) were linked to FA modifications in developing white matter.
Conclusions:
- DTI metrics reveal distinct developmental patterns in rat gray and white matter.
- These findings provide a normative dataset for assessing the impact of perinatal injury on brain development.
- Temporal DTI changes reflect underlying processes of axonal pruning and myelination.
Abstract:
Perinatal hypoxia is a major cause of neurodevelopmental deficits. Neuronal migration patterns are particularly sensitive to perinatal hypoxia/ischemia and are associated with the clinical deficits. The rat model of hypoxia/ischemia at P7 mimics that of perinatal injury in humans. Before assessing the effects of postnatal injury on brain development, it is essential to determine the normal developmental trajectories of various brain structures in individual animals. In vivo longitudinal diffusion tensor imaging (DTI) was performed from postnatal day 0 (P0) to P56 on Wistar rats. The DTI metrics, mean diffusivity (MD), fractional anisotropy (FA), axial (lambdal) and radial (lambdat) diffusivities, were determined for four gray matter and eight white matter structures. The FA of the cortical plate and the body of corpus callosum decreased significantly during the first 3 weeks after birth. The decrease in the cortical plate's FA value was associated mainly with an increase in lambdat. The initial decrease in FA of corpus callosum was associated with a significant decrease in lambdal. The FA of corpus callosum increased during the rest of the observational period, which was mainly associated with a decrease in lambdat. The FA of gray matter structures, hippocampus, caudate putamen, and cortical mantle did not show significant changes between P0 and P56. In contrast, the majority of white matter structures showed significant changes between P0 and P56. These temporal changes in the DTI metrics were related to the neuronal and axonal pruning and myelination that are known to occur in the developing brain.
