Y-CHROMOSOMAL EFFECTS ON HIPPOCAMPAL MOSSY FIBER DISTRIBUTIONS IN MICE SELECTED FOR AGGRESSION

The influence of the non-pseudoautosomal region of the Y chromosome (Y -NPAR) On the sizes of the hippocampal intra- and infrapyramidal messy fiber (IIPMF) terminal fields was examined in wild house mice. For th is purpose selection lines for short attack latency (SAL), long attack latency (LAL), and their respective congenics for the Y-NPAR were use d. We found an incremental effect of the (non-aggressive) LAL Y-NPAR, combined with an additive effect of the line background on the sizes o f the IIPMF terminal fields. In contrast, only the line background aff ected attack latency. The implications of this finding for the previou sly observed correlation between the size of the IIPMF and aggression in male house mice are discussed.