Wheel running induces conditioned taste aversion in rats trained while hungry and thirsty

Area of Science:

• Behavioral Neuroscience
• Animal Psychology

Background:

• Activity anorexia is a phenomenon where rats reduce food intake when provided with running wheels.
• The underlying mechanisms, particularly the role of sickness, are not fully understood.

Purpose of the Study:

• To investigate if wheel running can induce sickness in rats.
• To determine if sickness associated with wheel running leads to conditioned flavor aversion.
• To explore the implications for activity anorexia and human anorexia nervosa.

Main Methods:

• Rats were exposed to either a salt or sour solution followed by wheel running.
• Control conditions involved exposure to solutions without wheel running.
• Conditioned aversion was assessed by observing solution preference after training.

Main Results:

• Conditioned aversion to the flavor paired with wheel running was observed after two pairings.
• This aversion persisted even when the rats' deprivation state changed from training to testing.
• The findings suggest wheel running can induce a sickness-like state.

Conclusions:

• Wheel running can act as a sickness-inducing stimulus in rats.
• Sickness-induced conditioned flavor aversion may contribute to activity anorexia.
• This provides a potential link between sickness and eating disorders like anorexia nervosa.