Accelerated nervous system development contributes to behavioral efficiency in the laboratory mouse: A behavioral review and theoretical proposal

Abstract

The emergence of the laboratory mouse as a favored species for genetic research has posed a number of problems for scientists interested in the reflection of genetic influences in mouse behavior. It is commonly thought that rat behavior, which has been studied more extensively than mouse behavior, could be easily generalized to mice. In this article, a number of categories of behavior displayed by the mouse (motor, spatial, defensive, social) are reviewed and contrasted with the same categories of behavior displayed by the rat. The comparison suggests that mouse behavior is simpler and more dependent upon elementary actions than the behavior of the rat. We suggest that the behavioral simplification in the mouse adapts it for a different ecological niche than that occupied by the rat. We propose that this simplification may be mediated by accelerated brain maturation during development. We further propose that this developmental acceleration in the mouse renders it less dependent upon complex social behavior and plastic nervous system changes associated with learning than the rat. This difference poses problems for the development of relevant methods of behavioral analysis and interpretation. Since the mouse's biological adaptations will be reflected in laboratory behavior, suggestions are made for behavioral approaches to the study and interpretation of mouse behavior.

Axonal ribosomes and mRNAs associate with fragile X granules in adult rodent and human brains

“…For example, mice are exclusively terrestrial while rats are also arboreal and aquatic (54,55). Rats also show superior performance across a broader array of spatial learning tasks, exhibit better spatial learning retention, and are more adept at using flexible spatial strategies to solve problems (56)(57)(58)(59)(60). One intriguing hypothesis is that axonal translation in the adult rat hippocampus supports the formation and experiencedependent modification of broad territory maps required to navigate larger and more varied habitats.…”

Activation of ERK/MAPK in the Lateral Amygdala of the Mouse is Required for Acquisition of a Fear-Potentiated Startle response

“…In contrast with Paul et al (2007), who found in the rat a second peak of activation at 5 min after fear conditioning, even higher than the one at 60 min, we could not find any evidence for this second peak of phospho-activated labeled cells in the mouse (Figure 2b). As reviewed in Whishaw et al (2001), several comparative studies already described anatomical and behavioral differences between the mouse and the rat in their performance in various behavioral tests. Therefore, researchers have an increasing awareness that these differences may complicate and limit the use of rat studies to interpret findings in mice (Asan et al, 2005;Jardim et al, 1999).…”

Colony formation of C57BL/6J mice in visible burrow system: Identification of eusocial behaviors in a background strain for genetic animal models of autism

“…When the targeted gene is expressed in the brain, the behavioral phenotype of the genetically-manipulated mice may reveal genetic mechanisms underlying behaviors. Mice are a relatively social species [25,37,63]. Suitable mouse models for autism would show some relationship to the types of social deficits that are considered core symptoms of autism, including very low levels of eusocial behaviors and deficits in maintaining peer relationships [23,41].…”