Acquisition, Extinction, Recovery, and Reversal of Different Response Sequences Under Conditional Control by Nicotine in Rats

Abstract

Complex voluntary behaviors occur in sequence. Eight rats were trained in an operant procedure that used nicotine and non-drug (saline) states as interoceptive cues that signaled which of two behavioral sequences led to food reward. The distal and proximal responses in the chain were always maintained on variable interval 30-sec and fixed ratio-1 schedules, respectively, and rate differences between the responses were used as the dependent variable. Extinction and reversal training was conducted. Distal response rates were significantly greater than proximal response rates during training, testing, extinction, and reversal learning. These data suggest that (a) nicotine can establish interoceptive control over different response sequences, and (b) extinction of one response sequence may be state-dependent. The clinical relevance of extinction of complex behavioral repertoires such as drug-seeking and drug-taking behavior that are evoked by specific interoceptive cues is addressed in regard to drug abuse treatment and relapse.

Exploring the interoceptive stimulus effects of nicotine and varenicline

“…That study used a reversal of an operant-chain in a discrimination task. While this interesting study is quite different from the one reported herein, it does show that the nicotine stimulus was sensitive to a shift in reinforcers relations; for more detail see Troisi (2013). The present research extends the observation of reversal learning to the DGT task.…”

“…Interestingly, we found that the stimulus-sucrose relation used in discrimination training with a 0.4 mg/kg nicotine versus saline stimulus was reversible as evidenced by the acquisition of the discrimination in the NIC-group. There is a dearth of literature on reversal learning using drug discrimination and only one known to us for a discrimination involving the nicotine stimulus (see Troisi, 2013). Interestingly, we found that a 1 mg/kg varenicline stimulus fully substituted for the 0.4 mg/kg nicotine stimulus when drug sessions continued to be reinforced (i.e., VAR+).…”

“…Pavlovian-reversal learning studies have also been conducted using exteroceptive stimuli (Bouton & Brooks, 1993;Chudasama & Robbins, 2003) and interoceptive conditioned responses such as heart rate (Tighe, Graves, & Riley, 1968). To our knowledge the only example of reversal learning within a discrimination task using an interoceptive nicotine stimulus was reported by Troisi (2013). That study used a reversal of an operant-chain in a discrimination task.…”

Configurations of the interoceptive discriminative stimulus effects of ethanol and nicotine with two different exteroceptive contexts in rats: Extinction & recovery

“…Nicotine has been shown to increase conditioned reinforcing effects of exteroceptive contextual stimuli (Chaudhri et al, 2006) and promote differences in attention and learning (Semenova et al, 2007). In a recent study, nicotine promoted stronger reversal learning of response chains than saline (Troisi, 2013a). It has also been suggested that nicotine may promote stronger changes in excitatory strength in accord with the Rescorla and Wagner (1972) model thus promoting deepened extinction (Rescorla, 2006;Troisi, 2011;Troisi et al, 2013).…”

Can the discriminative stimulus effects of nicotine function concurrently as modulatory opponents in operant and pavlovian occasion setting paradigms in rats?

“…From a more translational perspective, drug seeking and drug taking behavior represent a complex behavioral repertoire with both antecedent stimulus conditions (interoceptive and exteroceptive) and consequential outcomes (Troisi, 2013b,c). Although they can function independently, Pavlovian and operant contingencies ultimately interact in modulating drug seeking and drug self-administration (Troisi, 2013b,c; Hogarth & Troisi, 2015). Here we showed how interoceptive stimulus control by nicotine simultaneously functions in dual antecedent roles in co-modulating operant and Pavlovian-evoked goal-directed behavior.…”