Motor deficits and neurofibromatosis type 1 (NF1)-associated MRI impairments in a mouse model of NF1.

Neurofibromatosis type 1 (NF1) is a genetic disorder characterized inter alia by cognitive and motor dysfunction and appearance of high-signal foci on T2-weighted images in the brain. Nf1(+/-) mice are useful models for studying aspects of NF1, including cognitive deficits. Here we assessed their motor performance and used quantitative transverse T2 relaxation MRI to identify structural abnormalities in their brains. Nf1(+/-) mice exhibited both enhanced and reduced T2 signals in distinct brain regions compared to wild-type mice, and their motor performance was impaired. As in NF1 patients, enhanced T2 signals in Nf1(+/-) mice were observed in the thalamus and basal ganglia. Reduced T2 signals were seen in motor-associated regions along the motor pathway, predominantly in the white matter of the cerebral peduncle and the optic tract. Correlation analysis between T2 signals and motor performance suggested that the motor deficits are associated with impairments in the cerebral peduncle and the amygdala.