Behavioural testing of standard inbred and 5HT(1B) knockout mice: implications of absent corpus callosum.

Rapid advances in biotechnology have created new demands for tests of mouse behaviour having both high reliability and high throughput for mass screening. This paper discusses several statistical and psychological factors pertinent to replication of results in different laboratories, and it considers the question of which inbred strains are best for test standardization. In this context, the problem of absent corpus callosum in the 129 strains is addressed with data from a recent study of six diverse tests of behaviour, and it is shown that effects of absent corpus callosum are usually nonsignificant and/or very small. Whether any 129 substrain is to be included in the list of standard strains depends on the goal of the standardization--collecting diverse phenotypic data on most available strains by a few expert investigators (the gold standard) or refining behavioural tests in order to establish a normal range of behaviour that can be used to judge a wider range of strains or even an individual mouse.