Pavlovian extinction reduces the performance of conditioned responses and occurs when the conditioned stimulus (CS) is repeatedly presented in the absence of the unconditioned stimulus (US). However, when the CS is experienced in a context that is different from the extinction context, there is a recovery of the conditioned response, a phenomenon known as renewal. There is some evidence that the renewal of appetitive conditioning is influenced by sex, with females failing to exhibit renewed responding.
View Article and Find Full Text PDFFear memory retrieval is relevant to psychiatric disorders such as post-traumatic stress disorder (PTSD). One of the hallmark symptoms of PTSD is the repeated retrieval and re-experiencing of the initial fear memory even long after the traumatic event has occurred. Women are nearly twice as likely to develop PTSD following a trauma than men, thus sex differences in the retrieval of fear memories is highly relevant for understanding the development and maintenance of PTSD.
View Article and Find Full Text PDFIn resurgence, an operant behavior that has undergone extinction can return ("resurge") when a second operant that has replaced it itself undergoes extinction. The phenomenon may provide insight into relapse that may occur after incentive or contingency management therapies in humans. Three experiments with rats examined the impact of several variables on the strength of the resurgence effect.
View Article and Find Full Text PDFJ Exp Psychol Anim Behav Process
July 2012
Three experiments with rats examined the effects of thinning the rate of reinforcement for the alternative behavior in the resurgence paradigm. In all experiments, pressing one lever (L1) was first reinforced and then extinguished while pressing a second alternative lever (L2) was then reinforced. When L2 responding was then extinguished, L1 responses "resurged.
View Article and Find Full Text PDFIt is widely recognized that extinction (the procedure in which a Pavlovian conditioned stimulus or an instrumental action is repeatedly presented without its reinforcer) weakens behavior without erasing the original learning. Most of the experiments that support this claim have focused on several "relapse" effects that occur after Pavlovian extinction, which collectively suggest that the original learning is saved through extinction. However, although such effects do occur after instrumental extinction, they have not been explored there in as much detail.
View Article and Find Full Text PDFObesity and overeating have become fundamental problems in modern society. This article studies the inhibition of food-seeking behavior, and how contextual cues can control it. Rats that had free food in the home cage nevertheless learned to lever press for sucrose or high-fat pellets in a distinctive context (a Skinner box).
View Article and Find Full Text PDFFour experiments with rat subjects examined the role of context during the extinction of instrumental (free-operant) behavior. In all experiments, leverpressing was first reinforced on a variable-interval 30-s schedule and then extinguished before being tested in the extinction and renewal contexts. The results identified three important variables affecting the renewal effect after instrumental extinction.
View Article and Find Full Text PDFThree experiments with rat subjects examined resurgence of an extinguished instrumental response using the procedure introduced by Epstein (1983) with pigeons. There were three phases: (1) initial acquisition of pressing on a lever (L1) for pellet reward, (2) extinction of L1, and (3) a test session in which a second lever (L2) was inserted, briefly reinforced, and then extinguished. Experiment 1 confirmed that if pressing L2 delivered 20 pellets followed by extinction, rats would resume L1 responding in the final test.
View Article and Find Full Text PDFFour experiments were performed to explore the role of context in operant extinction. In all experiments, leverpressing in rats was first reinforced with food pellets on a variable interval 30-s schedule, then extinguished, and finally tested in the same and a different physical context. The experiments demonstrated a clear ABA renewal effect, a recovery of extinguished responding when conditioning, extinction, and testing occurred in contexts A, B, and A, respectively.
View Article and Find Full Text PDFJ Exp Psychol Anim Behav Process
July 2010
Four experiments examined "resurgence" of an instrumental behavior after extinction. All experiments involved three phases in which rats were (1) trained to press one lever for food reward, (2) trained to press a second lever while the first leverpress was extinguished, and (3) tested under conditions in which neither leverpress was rewarded. In each experiment, the first leverpress recovered (resurged) in Phase 3, when the second leverpress was extinguished.
View Article and Find Full Text PDFThree appetitive conditioning experiments with rats examined temporal discrimination learning within Pavlovian conditioning trials. In all experiments, the duration of a feature white noise stimulus signaled whether or not a subsequent 10-s target tone would be reinforced. In Experiment 1, the feature durations were 4 and 1min.
View Article and Find Full Text PDFThe current study investigated the contribution of the dorsomedial prefrontal cortex (dmPFC) to instrumental action selection. We found that cell body lesions of the dmPFC, centered on the medial agranular area, spared rats' ability to choose between actions based on either the value or the discriminative stimulus properties of an outcome. We next examined the effects of these lesions on action sequence learning using a concurrent bidirectional heterogeneous chain task in which the identity of the reward delivered was determined by the order in which the two lever press actions were performed.
View Article and Find Full Text PDFIn four experiments we assessed the effect of systemic amphetamine on the ability of a stimulus paired with reward and a stimulus that was not paired with reward to support instrumental conditioning; i.e., we trained rats to press two levers, one followed by a stimulus that had been trained in a predictive relationship with a food outcome and the other by a stimulus unpaired with that reward.
View Article and Find Full Text PDFTwo experiments examined the motivational specificity of the associations that support 2nd-order conditioning. In the 1st phase of each experiment rats were exposed to 2 visual conditioned stimuli (CSs) paired with either a saline or food pellet unconditioned stimulus (US) prior to exposure to 2nd-order conditioning using 2 auditory CSs, 1 paired with each visual CS. Rats' motivational state was then shifted prior to a test such that if and only if specific motivational features of the 1st-order training US played a role in the 2nd-order associative structure would responding to the 2nd-order cues shift appropriately with the state change.
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