Three-dimensional high-resolution diffusion tensor imaging and tractography of the developing rabbit brain.

Area of Science:

• Neuroscience
• Biomedical Imaging

Background:

• Diffusion tensor imaging (DTI) is sensitive to structural organization in brain white matter.
• Diffusion anisotropy, a measure of structural ordering, changes during neural development and in disease states.

Purpose of the Study:

• To investigate developmental changes in regional diffusion anisotropy and white matter fiber tract development using high-resolution DTI.
• To assess the utility of ex vivo DTI tractography in neuroscience research.

Main Methods:

• High-resolution DTI was performed on fixed rabbit brains at various postnatal ages using a 4.7-tesla Bruker Biospec Avance scanner.
• Trace apparent diffusion coefficient, fractional diffusion anisotropy maps, and fiber tracts were generated and compared across ages.
• Regional DTI tractography focused on the internal capsule and callosal commissure.

Main Results:

• The rabbit brain exhibited high anisotropy at birth, with increasing white matter anisotropy correlating with age.
• Maturation led to refinement in the regional tract architecture of the internal capsule.
• Brains with callosal commissure deficiencies displayed distinct fiber architecture compared to age-matched controls.
• Reproducibly coherent fiber tracts corresponding to known corticospinal and corticobulbar anatomy were identified in the internal capsule.

Conclusions:

• Ex vivo DTI tractography is a powerful tool for neuroscience, capable of revealing developmental effects like fiber tract pruning.
• This technique may identify important targets for in vivo human studies.
• DTI provides detailed insights into white matter development and structural connectivity.