As direct evaluation of a mouse model of human neurodevelopment, adolescent and young adult mice and humans underwent MR diffusion tensor imaging to quantify age-related differences in microstructural integrity of brain white matter fibers. Fractional anisotropy (FA) was greater in older than younger mice and humans. Despite the cross-species commonality, the underlying developmental mechanism differed: whereas evidence for greater axonal extension contributed to higher FA in older mice, evidence for continuing myelination contributed to higher FA in human adolescent development. These differences occurred in the context of species distinctions in overall brain growth: whereas the continued growth of the brain and skull in the murine model can accommodate volume expansion into adulthood, human white matter volume and myelination continue growth into adulthood within a fixed intracranial volume. Appreciation of the similarities and differences in developmental mechanism can enhance the utility of animal models of brain white matter structure, function, and response to exogenous manipulation.
Keyphrases
- white matter
- multiple sclerosis
- young adults
- endothelial cells
- high fat diet induced
- depressive symptoms
- mouse model
- induced pluripotent stem cells
- mental health
- pluripotent stem cells
- middle aged
- type diabetes
- spinal cord injury
- early life
- insulin resistance
- magnetic resonance
- skeletal muscle
- metabolic syndrome
- subarachnoid hemorrhage