MRI description of cerebral atrophy in mouse lemur primates.

We assessed cerebral atrophy in mouse lemur primates (Microcebus murinus) by estimating CSF volume in their brains from 4.7 Tesla T2-weighted magnetic resonance images. Thirty animals aged from 1 to 10.3 years were imaged, 14 of them were followed for up to 2 years. Seven of these animals were examined for neuropathology. In 12 out of 17 animals older than 3.5 years, CSF volumes were increased. A subgroup of six animals had severe atrophy of the temporal lobe. Another subgroup of five animals displayed diffuse atrophy in addition to the temporal atrophy. One animal had a dilation of the external part of the temporal horn of the lateral ventricle in addition to the temporal atrophy. The three animals with diffuse atrophy that could be studied for neuropathology had diffuse cerebral amyloid deposits detected by immunocytochemistry. The other animals did not display amyloid deposits. Relations between the different types of atrophy as well as their causes will have to be assessed in future studies.