Hippocampal mossy fiber distribution covaries with open-field habituation in the mouse.

We studied the sizes of the hippocampal intra- and infrapyramidal mossy fiber (iip-MF) terminal fields and habituation to a new environment (open-field) in 25 genetically different groups of mice. Based on previous findings and theoretical considerations, a positive relationship between the size of the iip-MF terminal fields and the extent of behavioral change between two subsequent exposures to the open-field was expected. In fact, such a relationship was revealed by a factor analysis. Our results indicate that mice possessing large iip-MF terminal fields are more efficient in the processing of spatial information.