Pharmacological validation and behavioural characterisation of Approach-Avoidance Foraging

Abstract

Approach-avoidance foraging (AAF) has received increasing interest as a novel test of rodent anxiety in recent years, yet this paradigm remains unvalidated pharmacologically and rodent behaviour and behavioural adaption during the task has not been described in any detail. This study characterised how behaviour within AAF was altered following experience, or as a result of modulating anxiety pharmacologically. In an indirect-threat variation of AAF, animals were required to retrieve food rewards in a brightly lit foraging arena to a maximum distance of 150cm from a home area. After reaching criterion, animals foraged after receiving the anxiogenic FG7142 (7.5mg/kg, n = 9), the anxiolytic Diazepam (1mg/kg, n = 9) or Vehicle (n = 7). When foraging with greater experience animals displayed a significant reduction in latency to enter the arena (p = 0.0001), duration of scanning behaviour (p = <0.0001), frequency of stretch-and-attend postures (SAPs) (p = <0.0001) and number of failed retrieval attempts (p = 0.0387). Treatment with FG7142 significantly reduced rodents’ rate of successful reward retrieval (p = 0.0198). Animals receiving FG7142 displayed significantly decreased peak speed attained on approach to the reward (p = 0.0284), increased the frequency of SAPs (p = 0.0113) and displayed a trend to extend the duration of scanning behaviour (p = 0.0511). No significant effect was detected on any recorded parameter following treatment with the anxiolytic Diazepam (1 mg/kg-1). These results demonstrate that anxiety-like behaviour is reduced within AAF as a result of experience and confirm that performance within AAF is dependent upon anxiety levels. This work also defines an anxious behavioural phenotype to aid future users of AAF in detecting subtle anxiogenic effects

Date of Award	19 Mar 2019
Original language	English
Awarding Institution	University of Bristol
Supervisor	Bridget M Lumb (Supervisor) & Richard Apps (Supervisor)