Exploration and learning behavior in mice selectively bred for high and low levels of activity

Abstract

The open-field behavior of mice selectively bred for high and low activity and of unselected controls was studied in detail. The behavior was scored, at 3-sec intervals for 20 min, into one of six categories: air sniffing, rearing, grooming, locomotion, sniffing at objects, and freezing. The selective breeding had been very effective in changing the behavioral profile of the selected mice when compared to the control stock. The inactive mice did not freeze more frequently; instead, their behavior was characterized by more passive exploration (sniffing in particular) which became less pronounced as the observation period progressed. Previous reports in the behavior genetics literature had suggested a relationship between learning and exploratory or emotional behavior. It was hypothesized that the selectively bred mice would also differ with respect to their learning behavior. No differences were found between the active and inactive mice in wheelturn avoidance learning. The inactive mice were significantly slower than the active mice in running through a Lashley III maze, but there were no significant differences in the number of errors made. It was concluded that learning and exploratory behavior are not related in any simple manner in the mouse.