Repeated Cocaine Exposure Attenuates the Desire to Actively Avoid: A Novel Active Avoidance Runway Task.

David Nguyen,Rutsuko Ito,Yasika Nesarajah,Suzanne Erb

doi:10.3389/fnbeh.2018.00108

David Nguyen, Rutsuko Ito + Show 2 more

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https://doi.org/10.3389/fnbeh.2018.00108

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Abstract

Drug addiction is a disorder in which drug seeking persists despite aversive consequences. While it is well documented in animal models of drug sensitization that repeated drug exposure enhances positive incentive motivation for drug and natural reinforcers, its effect on negative incentive motivation, defined here as the motivation to avoid a cued aversive outcome, remains an open question. In the present study, we designed a novel active avoidance (AA) runway paradigm to assess the effects of repeated cocaine exposure on the motivation to avoid an aversive outcome. Cocaine and saline pre-exposed rats were first trained to perform a conditioned AA lever press response to prevent the occurrence of foot shock administrations. The rats were subsequently tested in a runway apparatus, wherein they were required to traverse the length of a straight alley maze to reach the lever and emit a conditioned AA response. Run times were measured as an indication of negative incentive motivation. Cocaine pre-exposed rats demonstrated longer latencies to emit the conditioned AA response but showed no differences in latency to initiate runway behavior, nor in their acquisition of the AA response compared to the saline pre-exposed controls. Subsequent testing in an elevated plus maze revealed no differences in the expression of anxiety in cocaine pre-exposed rats compared to saline pre-exposed controls. Our results indicate that prior repeated cocaine exposure attenuated cued negative incentive motivation, which suggests that drug addiction may be attributable to a decrease in motivation to avoid aversive consequences associated with drug use.

Highlights

Drug addiction is a disorder characterized by compulsive drug-seeking and taking behaviors that persist despite the recurrent experience of negative consequences
We recently examined the effect of prior subchronic cocaine exposure on approach-avoidance motivation for a natural sucrose reward paired with foot shock punishment (Nguyen et al, 2015)
multivariate analysis of variance (MANOVA) performed on the AA acquisition data (Figure 2A) revealed a significant main effect of Response type (F(1,12) = 30.376, p < 0.0001), with the data indicating that more AA responses than escape responses were emitted overall during the AA training phase

Summary

Introduction

Drug addiction is a disorder characterized by compulsive drug-seeking and taking behaviors that persist despite the recurrent experience of negative consequences. It is possible that compulsive forms of drug-seeking are manifestations of aberrant processing of competing motivational signals: those that simultaneously compel the individual to seek and avoid the Cocaine Pre-exposure and Negative Incentive Motivation drug (Nguyen et al, 2015). A history of sugar bingeing can lead to increased ethanol intake and a potentiated locomotor response to amphetamine (AMPH; Avena and Hoebel, 2003; Avena et al, 2004) Based on these findings, we recently examined the effect of prior subchronic cocaine exposure on approach-avoidance motivation for a natural sucrose reward paired with foot shock punishment (Nguyen et al, 2015). An alternative possibility is that the observed shorter latencies to enter the shock-paired compartment in the cocaine pre-exposed rats were attributable to an attenuation of negative reinforcement, or ‘‘negative incentive motivation,’’ which in this case would apply to the motivation to avoid entering the goal compartment in order to escape the negative foot shock consequences altogether

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