Studies of Impulsivity in Rats in Conditions of Ch

Authors: M I Zaichenko G Kh Merzhanova

Publish Date: 2011/05/25

Volume: 41, Issue: 5, Pages: 445-451

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Abstract

The behavior of rats was studied in conditions of having the “right” to select reinforcement on the basis of its value depending on the duration of the delay to its receipt Rats were placed in a chamber fitted with two movable pedals pressing on one of which yielded lowvalue food reinforcement one pellet while pressing the other led to delivery of a highervalue four pellets but delayed reinforcement Rats preferring the lowvalue reinforcement without a delay were regarded as “impulsive” while those preferring the highervalue reinforcement with the delay were regarded as “selfcontrolled” The behavioral characteristics of the rats of these two groups were studied during execution of an operant pedalpressing reaction as were the effects of the duration of the reward delay and changes in the level of motivation to select the pedal to receive reinforcement Preference for selecting the pedal to receive one reinforcement or the other was assessed and the durations of the latent periods of pedalpressing and the numbers of omitted reactions were evaluated “Impulsive” animals were found to press the pedal significantly more quickly and to omit fewer pedal presses than “selfcontrolled” animals Increases in the delay duration to 7 sec led to refusal to select the pedal yielding the delayed reinforcement Strengthening of food motivation pushed to rats’ behavior towards “self control” while sated rats more frequently preferred the less valuable but rapidly delivered reinforcement

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