Structural asymmetries in brains of mice selected for strong lateralization.

The brains of 18 female mice from two lines selectively bred for lateralization of paw preference were investigated for morphological asymmetries in 5 horizontal sections from mid-dorsoventral planes. Cortical thickness was measured at orbitofrontal, somatosensory and lateral entorhinal regions; volume measures included the hippocampal formation and the striatum. Mice of the strongly lateralized line had stronger asymmetries in 4 of the 5 variables. Discriminant analysis showed that the two mouse lines could be differentiated best by their asymmetries in orbitofrontal cortex and hippocampus (P less than 0.02).