Strain and sex differences on olfactory discrimination learning in C57BL/6J and DBA/2J inbred mice (Mus musculus)

In this study, the authors explored potential strain and sex differences in nonspatial cognitive ability. Beginning around 90 days of age, male;md fem ale C57BL/6J (C57) and DBA/2J (DBA) inbred mice (Mus musculus) were tested on a task of simple odor discrimination learning with 3 repeated reversals. Males learned the task more readily than females, and DBA mice learned the task more readily than C57 mice. All differences became evident after repe ated testing. Similarity of perseveration measures indicated the difference s were not due to inhibitory deficits. Instead, a phase analysis localized differences to a transitional period of reversal learning. Females increase d transitional errors that more likely indicated adaptive sampling strategi es than memory failures. C57 females used this strategy indiscriminately, b ut DBA females sampled as a function of environmental uncertainty.