Neuroanatomy of the fragile X knockout mouse brain studied using in vivo high resolution magnetic resonance imaging.

Magnetic resonance imaging (MRI) of the brain of fragile X patients, the most frequent form of inherited mental retardation, has revealed abnormalities in the size of specific brain structures, including the cerebellar vermis, the hippocampus, and the ventricular system. We intended to quantify the differences observed in the patient studies in the fragile X knockout mouse model, which is a good model for the disease, paralleling the human disorder in having cognitive deficits, macro-orchidism, and immature dendritic spines. Therefore we set up MRI of the mouse brain which allowed us to measure the size of the brain structures reported to be abnormal in human fragile X patients in the mouse model. We did not find evidence for size alterations in various brain regions of the fragile X mouse model, but the method described may find a wide application in the study of mutant mouse models with neurological involvement.