\u2018Waiting impulsivity\u2019 in isolation-reared and socially-reared rats: effects of amphetamine

Yia-Ping Liu,Lawrence S Wilkinson,Trevor W Robbins

doi:10.1007/s00213-017-4579-8

Yia-Ping Liu, Lawrence S Wilkinson + Show 1 more

Open Access

https://doi.org/10.1007/s00213-017-4579-8

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Abstract

BackgroundRats reared in social isolation exhibit various cognitive and behavioural abnormalities in adulthood. However, impulsivity following this treatment still remains unclear, especially in response to medications used in attention deficit hyperactivity disorder, such as amphetamine.MethodsUsing an isolation-rearing (IR) manipulation, the present study examined the effects of IR on impulsive action and impulsive choice when also treated with doses of d-amphetamine, by employing the five-choice serial reaction time task (5-CSRTT) and a temporal discounting of reward task (TDRT), respectively.ResultsIR rats showed similar acquisition of the 5-CSRTT. Amphetamine increased premature responding in both groups; however, IR rats showed less responding overall. For the TDRT, IR rats revealed a greater preference for the large but delayed reward during task acquisition (i.e. were less impulsive) with a higher rate of nose poking during the delay, and exhibited a compressed dose-response function (i.e. reduced dose sensitivity) for amphetamine.DiscussionImpulsive action and impulsive choice were reduced in IR rats under certain conditions, and a blunted response to d-amphetamine was found on these measures. These reductions in impulsivity contrast with locomotor hyperactivity normally shown in IR rats and the findings have implications for the utility of IR as a model of psychopathology.

Highlights

Life experience in humans can have major influences on behaviour and cognition in the adult (Bowlby 1969; Erikson 1975; Moutsiana et al 2014)
Impulsive action and impulsive choice were reduced in IR rats under certain conditions, and a blunted response to D-amphetamine was found on these measures
Rearing condition had no effects on acquisition sessions to reach the criteria of task performance for 5-CSRTT in percent correct, correct latency and premature responses [percent correct, F(1,22) = 0.07; correct latency, F(1,22) = 0.05; premature

Summary

Introduction

Life experience in humans can have major influences on behaviour and cognition in the adult (Bowlby 1969; Erikson 1975; Moutsiana et al 2014). ADHD entails symptoms of impulsivity (i.e. either ‘impulsive action’ or increased ‘impulsive choice’ for smaller sooner rewards compared with delayed, larger ones, i.e. during the temporal discounting of reward task, TDRT), and inattention (Sjöwall et al 2013). Both impulsive action (as premature responses) and attention can be measured in the five-choice serial reaction time task (5CSRTT) (Robbins 2002). Rats reared in social isolation exhibit various cognitive and behavioural abnormalities in adulthood Impulsivity following this treatment still remains unclear, especially in response to medications used in attention deficit hyperactivity disorder, such as amphetamine. For the TDRT, IR rats revealed a greater preference for the large but delayed reward during task acquisition (i.e. were less impulsive) with a higher rate of nose poking during the delay, and exhibited a compressed dose-response function (i.e. reduced dose sensitivity) for amphetamine

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