The prelimbic cortex uses contextual cues to modulate responding towards predictive stimuli during fear renewal

Abstract

Previous research suggests the prelimbic (PL) cortex is involved in expression of conditioned fear (Burgos-Robles, Vidal-Gonzalez, & Quirk, 2009; Corcoran & Quirk, 2007). However, there is a long history of research in the appetitive domain which implicates this region in using higher-order cues to modulate a behavioural response (Birrell & Brown, 2000; Floresco, Block, & Tse, 2008; Marquis, Killcross, & Haddon, 2007; Sharpe & Killcross, 2014). For example, the PL cortex is necessary to allow animals to use contextual cues to disambiguate response conflict in ambiguous circumstances (Marquis et al., 2007). Using an ABA fear renewal procedure, we assessed the role of the PL cortex in using contextual cues to modulate a response towards a conditioned stimulus (CS) in an aversive setting. We found that pre-training lesions of the PL cortex did not impact on the expression or extinction of conditioned fear. Rather, they selectively abolished renewal. Functional inactivation of the PL cortex during extinction did not disrupt the subsequent renewal of conditioned fear or the ability of animals to exhibit fear towards a CS during the extinction session. However, PL inactivation during the renewal test session disrupted the ability of animals to demonstrate a reinstatement of responding in the renewal context. An analysis of orienting responses showed that renewal deficits were accompanied by a lack of change in attentional responding towards the CS. These data suggest the PL cortex uses contextual cues to modulate both a behavioural and an attentional response during aversive procedures. We argue that the role of the PL cortex in the expression of conditioned fear is to use higher-order information to modulate responding towards predictive cues in ambiguous circumstance.

Keywords: Associative learning; Attention; Behavioural flexibility; Fear renewal; Prelimbic cortex.