Neuroanatomy of cerebellum and olfactory bulb in a substrain of C57BL/6J inbred mice carrying a spontaneous mutation

Mice of the inbred C57BL/6JNmg substrain carry a mutation decreasing the si ze of the zinc-rich hippocampal intra- and infrapyramidal mossy fibre (IIPM F) terminal fields. In the present experiment, it was investigated whether this neurological mutation has also effects on other characteristics of the brain. No morphological differences were found in two other laminated neur al structures, the olfactory bulb, where the accessory granular layer is al so rich in zinc terminals, and the cerebellum. However, the mutants had a s omewhat inferior performance on a motor function task known to test cerebel lar involvement. The present findings confirm that previously found effects of this mutation on different types of behaviour are most probably due to the IIPMF. These substrains provide a powerful tool to localise the gene in volved and subsequently investigate the plausible pathways leading from gen e to behaviour. (C) 2001 Elsevier Science Inc. All rights reserved.