Personality, Performance, and Corticosterone in White-Footed Mice

Area of Science:

• Behavioral Ecology
• Neuroendocrinology
• Animal Physiology

Background:

• Previous studies indicate a negative correlation between exploration and locomotor performance in small rodents.
• Stressful conditions, such as novelty and forced exercise, may influence this relationship through glucocorticoid hormones.

Purpose of the Study:

• To investigate the role of corticosterone (a glucocorticoid hormone) in the negative relationship between exploration and sprint speed in white-footed mice.
• To determine how baseline and post-exercise corticosterone levels relate to both behavioral (exploration) and performance (sprint speed) measures.

Main Methods:

• Repeatedly measured exploration, sprint speed, and blood corticosterone levels in 51 captive female white-footed mice.
• Utilized novel environment tests for exploration and a racetrack for forced-exercise sprint speed.
• Analyzed correlations between behavioral measures, performance metrics, and both baseline and post-exercise corticosterone levels.

Main Results:

• Confirmed a negative correlation between exploration and sprint speed among individuals.
• Demonstrated contrasting relationships between corticosterone levels and behavior versus performance.
• Found that corticosterone levels partially explained the negative exploration-sprint speed correlation.

Conclusions:

• Glucocorticoid stress hormones play a significant role in mediating the trade-off between exploration and locomotor performance.
• The findings support the hypothesis that stress hormones contribute to the observed inverse relationship between these two traits in rodents.