The circadian Clock mutation increases exploratory activity and escape-seeking behavior

Area of Science:

• Neuroscience
• Behavioral Genetics
• Chronobiology

Background:

• Circadian rhythm disturbances are linked to mood disorders.
• The role of the circadian pacemaker as a primary cause of altered emotional behavior is not fully understood.

Purpose of the Study:

• To investigate if a dysfunctional circadian pacemaker, specifically the Clock gene mutation, can cause altered emotional behavior.
• To compare the behavioral effects of the Clock mutation in male and female mice.

Main Methods:

• Behavioral tests were used to assess exploratory activity, anxiety, and behavioral despair in Clock mutant and wild-type mice.
• Tests included the open field, elevated plus maze, and forced swim test.

Main Results:

• Female Clock mutant mice showed significantly increased activity, rearing, and exploration in the elevated plus maze.
• Both male and female Clock mutant mice exhibited increased swimming in the forced swim test, indicating escape-seeking behavior.
• Behavioral changes were more pronounced in female mice and were not dependent on a lengthened free-running period.

Conclusions:

• The Clock mutation leads to increased exploratory and escape-seeking behaviors, not increased anxiety or depression-like behaviors.
• The Clock gene is implicated in regulating behavioral arousal.
• Clock gene may interact with sex hormones to influence these behavioral changes.