Recovery of the rabbit’s conditioned nictitating membrane response without direct reinforcement after extinction

Abstract

Three experiments demonstrated that, following the extinction of an established conditioned stimulus (CSA--e.g., tone), the pairing of a novel, cross-modal stimulus (CSB--e.g., light) with the unconditioned stimulus (US) results in strong recovery of responding to the extinguished CSA. Experiment 1 demonstrated that the recovery of responding to CSA is not the result of US reinstatement but is attributable to pairings of CSB with the US. Experiment 2 demonstrated that the recovery of responding is specific to CSA and is not the result of cross-modal generalization. Experiment 3 revealed that a large number of CSB-US pairings in Stage 1 significantly reduced the amount of recovery to CSA during subsequent CSB-US trials. Experiment 3 also provided unexpected evidence of cross-modal secondary extinction. The extinction and subsequent recovery of responding seen in the present experiments is discussed with respect to possible contributions from contextual associations, CS processing, US processing, conditioned response expression, and layered excitatory associations.

Stimulus specificity of concurrent recovery in the rabbit nictitating membrane response

“…First, the test trials at the beginning of the very first session of Lϩ training provided an estimate of any residual spontaneous recovery of extinguished responding to T1. Second, the test trials at the start of the remaining sessions of Lϩ training allowed us to confirm that the recovery of responding is independent of any immediate aftereffects of training with the Lϩ trials and is retained from a previous session (Weidemann & Kehoe, 2004).…”

“…However, research in our laboratory has not revealed that reinstatement occurs in the rabbit NM preparation (Napier et al, 1992;Weidemann & Kehoe, 2004). Even repeated presentations of the US, which could cause reacquisition of context-US associations (Brandon & Wagner, 1991;Wagner & Brandon, 1989), do not result in discernible reinstatement of the CR to an extinguished CS (Weidemann & Kehoe, 2004).…”

“…With regard to external disinhibition and renewal, demonstrations of concurrent recovery have not involved presentation of CSA in a compound with either another discrete stimulus (external disinhibition) or a new context (renewal). With regard to reinstatement, previous tests of reinstatement in the rabbit NM preparation have repeatedly failed to reveal any significant recovery in responding to an extinguished CS as a result of US-alone presentations (Napier, Macrae, & Kehoe, 1992;Weidemann & Kehoe, 2004).…”

“…Recently, two studies with the rabbit NM preparation have examined the potential contribution of cross-modal generalization to concurrent recovery (Macrae & Kehoe, 1999;Weidemann & Kehoe, 2004). In both cases, the contribution was at most very small.…”

“…In both cases, the contribution was at most very small. For example, Weidemann and Kehoe (2004) conducted a within-subjects study of concurrent recovery in which stimuli from three different modalities (tone, light, and skin vibration) were assigned to roles as CSA, CSB, and CSC in a counterbalanced fashion. Initial CSA-US acquisition training was followed by CSAϪ extinction training and then CSB-US training.…”