title: Brain maturation of the adolescent rat cortex and striatum: changes in volume and myelination.
abstract: Longitudinal studies on brain pathology and assessment of therapeutic strategies rely on a fully mature adult brain to exclude confounds of cerebral developmental changes. Thus, knowledge about onset of adulthood is indispensable for discrimination of developmental phase and adulthood. We have performed a high-resolution longitudinal MRI study at 11.7T of male Wistar rats between 21days and six months of age, characterizing cerebral volume changes and tissue-specific myelination as a function of age. Cortical thickness reaches final value at 1month, while volume increases of cortex, striatum and whole brain end only after two months. Myelin accretion is pronounced until the end of the third postnatal month. After this time, continuing myelination increases in cortex are still seen on histological analysis but are no longer reliably detectable with diffusion-weighted MRI due to parallel tissue restructuring processes. In conclusion, cerebral development continues over the first three months of age. This is of relevance for future studies on brain disease models which should not start before the end of month 3 to exclude serious confounds of continuing tissue development.
authors.affiliation: In-vivo-NMR Laboratory, Max Planck Institute for Neurological Research, Cologne, Germany.
authors.forename: Luam
authors.initials: L
authors.lastname: Mengler
authors.forename: Artem
authors.initials: A
authors.lastname: Khmelinskii
authors.forename: Michael
authors.initials: M
authors.lastname: Diedenhofen
authors.forename: Chrystelle
authors.initials: C
authors.lastname: Po
authors.forename: Marius
authors.initials: M
authors.lastname: Staring
authors.forename: Boudewijn P F
authors.initials: BP
authors.lastname: Lelieveldt
authors.forename: Mathias
authors.initials: M
authors.lastname: Hoehn
mesh_terms: D000375:Aging / Q000473:pathology* / Q000502:physiology; D000818:Animals; D002540:Cerebral Cortex / Q000033:anatomy & histology* / Q000502:physiology; D003342:Corpus Striatum / Q000033:anatomy & histology* / Q000502:physiology; D056324:Diffusion Tensor Imaging; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000502:physiology / Q000648:ultrastructure*; D009929:Organ Size; D051381:Rats; D017208:Rats, Wistar
keywords: Age-dependent T2 relaxation changes; Age-dependent diffusion changes; Brain development; Myelination maturation; Tissue restructuring during cerebral development; Volume changes of cerebral structures during development