Reinstatement of conditioned fear and the hippocampus: An attentional-associative model

Abstract

An existing attentional-associative model of classical conditioning (Schmajuk, Lam, and Gray, 1996) is applied to the description of reinstatement in animals and humans. According to the model, inhibitory associations between the context (CX) and unconditioned stimulus (US) are formed during extinction, which help preserve the association between the conditioned stimulus (CS) and the US. However, summation and retardation tests fail to reveal these associations because (a) the CX is not attended or (b) a CX-CS configural stimulus formed during extinction is both poorly attended and weakly active during testing. When US presentations and testing occur in the same context, reinstatement is the consequence of a decreased CX inhibition and the increased attention to the CS, which activates the remaining CS-US association. When US presentations occur in the context of extinction but the CS is tested in a different context, reinstatement results from an increased attention to the CS and the combination of CS-CX and CX-US excitatory associations. The assumption that associations between CSs are impaired following neurotoxic hippocampal lesions or in amnesia, is sufficient to describe absence of reinstatement in those cases.

Connectionism and Classical Conditioning

“…However, it has recently been argued that inhibitory associations involving contexts are crucial to explaining many results, and are not easily detected experimentally because of attentional factors (Schmajuk, Larrauri, & Labar, 2007 Previously, we have seen that perceptrons can demonstrate blocking and conditioned inhibition. Therefore we should expect that another phenomenon can be produced in the perceptron: superconditioning.…”

“…Further to this, Schmajuk, Larrauri, and LaBar (2007) tested a neural network model of classical conditioning that incorporated attentional processes (Schmajuk, Lam, & Gray, 1996). As part of their study, Schmajuk, Larrauri and LaBar used this model to simulate an experiment whose results had previously been used to argue for inhibitory context (Bouton & King, 1983).…”

A review on human reinstatement studies: an overview and methodological challenges

“…This uncertainty about the predictive value of the CS may be derived from contextual conditioning during reinstatement: The context gains associative value through the unexpected presentation of the USs (Pearce and Hall 1980), which possibly shifts the balance of attention from a focus on the CS toward the context (Schmajuk et al 2007) and enhances contextual anticipatory anxiety (Grillon et al 2006). Upon subsequent, CS-recurrence, the discrimination of the previously US-predictive CS+ and nonpredictive (safe) CS2 might be challenged, as their predictive value for the US is attenuated as compared to the enhanced US predictive value of the context.…”

“…One attempt to model these results derived from rodent studies as well as one human study (LaBar and Phelps 2005) resulted in the attentional-associative model (Schmajuk et al 2007). According to this model, the CS and the context compete for attention with the US.…”

Deactivation and reactivation of the inhibitory power of a conditioned inhibitor: Testing the predictions of an attentional-associative model

“…Parameter values used in this article are identical to those used in Schmajuk and Larrauri (2006), Schmajuk, Larrauri, and LaBar (2007), and Larrauri and Schmajuk (2008).…”