Thesis (Ph.D.)--University of Delaware, 2009. / Principal faculty advisor: Arwen P. Mohun, Dept. of History. Includes bibliographical references.

Several lines of evidence suggest that initial acquisition of learned behavior involves multiple memory systems. In particular, lesions of the hippocampus impair the acquisition of cognitive or relational memory, but do not impair the acquisition of stimulus-response habits. Extinction behavior also involves new learning, and therefore it is possible that multiple forms of memory may also underlie extinction. We examined this hypothesis by training rats in a task in which extinction behavior could putatively be acquired by either a cognitive or habit memory system. Adult male Long-Evans rats were initially trained to run in a straight alley maze for food reward. Following training they were placed into one of two extinction conditions. In one condition rats were allowed to run to an empty goal box (i.e. response extinction). In a second condition rats were placed into an empty goal box without making a running response (i.e. latent or non-response extinction). Prior to each daily session of extinction training, rats received intra-hippocampal infusions of either the local anesthetic bupivacaine (0.75% solution/0.5 ul), or saline. Rats receiving saline infusions displayed extinction behavior in both the response and non-response conditions. In contrast, rats receiving intra-hippocampal infusions ofbupivacaine extinguished normally in the response condition, but did not display nonresponse extinction. This latent extinction effect was enhanced by decreasing the amount of time between the last extinction trial and the probe trial. Additionally, administering extinction training and probe trials in different contexts did not appear to prevent latent extinction, however large variability may be masking this effect. The new context administered during extinction prevented latent extinction in some animals, but not others. These findings suggest that, similar to initial acquisition, the learning that occurs during extinction also involves multiple memory systems. Specifically, the hippocampus may selectively mediate extinction under conditions in which new stimulus-response learning is prevented.

The aim of the present series of experiments was to outline the influence of different doses of cocaine during training, training schedule, training length and abstinence duration to modulate subsequent extinction and reinstatement patterns. Abram Amsel’s general theory of persistence were used to both design and explain various aspects of these models. For Experiment 1, rats self-administered cocaine (0.25, 0.50 or 1.00 mg/kg) intravenously and were then tested in an extinction preparation using saline infusions (5 days) and then only the stimulus light as the reinforcer (3 days). Experiment 2 examined schedules by magnitude interactions by training rats on two fixed-ratio (FR) schedules (FR-1 or FR-10 using either 0.25 or 1.00 mg/kg cocaine). Animals were tested in an extinction protocol (10 days; no stimulus light) and subsequently tested for reinstatement (1 day) that utilized presentations of the stimulus light. Experiment 3 addressed the effects of training length (15 or 30 days of training using either 0.25 or 1.00 mg/kg cocaine) using the same protocol as in Experiment 2. Experiment 4 examined the modulation potential of two abstinence lengths (15 or 30 days using either 0.25 or 0.50 mg/kg cocaine) using the same conditions as Experiment 2. Experiment 1 indicated the greatest resistance to extinction using the lowest training dose (0.25 mg/kg). The removal of saline caused an apparent extinction burst indicative of reward seeking. Experiment 2 showed that animals trained under partial reinforcement schedules persisted more during extinction. Furthermore, rats trained using 1.00 were more resistant than those trained with 0.25 mg/kg. Reinstatement of drug seeking was more pronounced in rats trained using an FR-10 schedule. Experiment 3 indicated greater resistance to extinction in rats trained for 15 versus 30 days. Rats trained on 0.50 mg/kg for 30 days showed less cue-induced reinstatement than those trained for 15 days. Experiment 4 showed increased resistance to extinction when rats were trained on 0.25 mg/kg and forced to abstain for 30 versus 15 days. Directionally opposite effects were apparent in groups trained with 0.50 mg/kg. Reinstatement data indicated greater responsivity to cues by animals abstaining for 30 versus 15 days.

“How to Achieve Extinction Without Killing Yourself: The Process of Writing a Screenplay” examines the creative procedure of writing the sci-fi feature Extinction. It explores the step-by-step process of idea genesis through to the third draft. / text

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Understanding the neural mechanisms underlying the extinction of maladaptive behaviors has become increasingly relevant. Extinction, or the reduction of a response due to lack of reinforcement, is believed to be “new learning.” Most extinction paradigms involve the performance of the previously reinforced response in the absence of reinforcement in order for extinction to occur. Conversely, latent extinction is a cognitive form of learning in which the previously rewarded response is not made during extinction training. However, until now the neurobiological basis of latent extinction has remained unknown. This dissertation has three aims to examine the neurobiological basis of latent extinction. Previous research has shown latent extinction to be impaired following hippocampal inactivation and the goal of Aim 1 was to examine other neural systems potentially involved in latent extinction through examination of brain structures such as the dorsal striatum, medial prefrontal cortex, and basolateral amygdala. Additionally, the neurochemical basis of latent extinction is unidentified; therefore Aim 2 addressed this question, specifically investigating the glutamatergic system through both NMDA receptor agonism and antagonism. Finally, understanding latent extinction may be useful for the extinction of drug addiction. Aim 3 was to examine some clinical implications for the extinction of drug addiction utilizing latent extinction following maze running for an oral cocaine reward. Reversible neural inactivation studies using the sodium channel blocker bupivacaine demonstrated a selective impairment of response extinction following dorsal striatum inactivation, but no effect on either latent or response extinction following medial prefrontal cortex or basolateral amygdala inactivation. These results, coupled with previous data from our lab demonstrate a double dissociation for extinction behavior. Further, peripheral NMDA receptor agonism with D-cyloserine enhances latent extinction and intra-hippocampal NMDA receptor antagonism with AP5 impairs latent extinction, identifying a role for the glutamatergic system in latent extinction. Finally, oral cocaine administration during acquisition selectively impairs latent extinction indicating that drug use affects the relive use of multiple memory systems during extinction. Overall, the multiple memory systems theory and latent extinction provide a framework with which to further understand the neural mechanisms of extinction behavior.

La volonté exprimée par le législateur de renforcer la place de la norme conventionnelle au sein du droit du travail, témoigne de l’importance devant être accordée à l’acte conventionnel de sa formation à son extinction, en passant par son exécution. Cette thèse aura ainsi pour objet d’étudier la phase d’extinction et plus spécifiquement les différents mécanismes conduisant à l’anéantissement des conventions et accords collectifs de travail. L’analyse de ces derniers conduit ainsi à opérer une distinction selon l’origine du fait générateur de l’extinction. L’extinction sera dite assumée lorsqu’elle sera la conséquence directe de la volonté des parties de mettre un terme à l’acte conventionnel. Un tel choix imposera dès lors le recours à la dénonciation ou bien aux conventions et accords à durée déterminée. Par opposition, l’extinction pourra être subie. L’anéantissement de l’acte s’imposera alors aux parties en raison de la survenance d’un événement déterminé. Dans pareilles circonstances, ce sont la mise en cause et la caducité qui devront alors être mises en oeuvre. La pluralité des situations que de tels mécanismes ont vocation à régir atteste de leur pertinence et de leur intérêt. Dès lors, au-delà de leur définition, c’est un régime complet de chacun de ces différents mécanismes d’extinction de l’acte conventionnel qui sera proposé au travers de cette étude. / The decision expressed by the legislator to strengthen conventional norm’s position in labor law, shows the importance of collective bargaining agreement from their conclusion through their application to their extinction. This PhD work aims to study the extinction phase and more precisely various mechanisms which lead to the end of collective bargaining agreements. There should be a clear distinction according to the origin of the operative event. Extinction will be shouldered when it will be the direct result of the choice made by the contracting parties to put an end to collective bargaining agreement. This choice will require the use of specific mechanisms such as denunciation or fixed term collective bargaining agreement. In contrast, extinction can be induced. Extinction should be binding on the parties because of a determinate event occurrence. In such cases different mechanisms have to be used such as caducity or « mise en cause ». These several situations show their relevance and interest. Therefore, beyond their definition a comprehensive scheme for each extinction mechanism will be suggested in this study.

The purpose of the present study was to experimentally investigate the effects of interspersing the opportunity to perform a fluent behavior during the acquisition of a new behavior. The experimenter trained left and right paw movements in domestic canines using a multiple treatment design. One paw movement was trained with a typical shaping procedure while the other was trained with an opportunity to perform a fluent behavior, touching the dog’s nose to a plastic disc, following each successive approximation in the shaping procedure. Two extinction phases were implemented during the experiment. The results showed that higher rates of reinforcement were achieved primarily following changes in criteria for reinforcement for the behavior in acquisition. There were no effects on rate of acquisition of the behavior, but adding an alternative fluent behavior may have slowed the differentiation between the reinforced behavior and alternative behaviors for one dog. The behavior trained with the addition of an alternative fluent behavior extinguished more quickly than in the control condition and extinguished at similar rates to the opposite leg movement. This suggests that the technique of offering an alternative fluent behavior may facilitate the chaining of the opposite behavior with the behavior targeted for reinforcement.

The following thesis is adapted from screenplay format. The document from which it derives serves as a shooting script for a film/video called A World Without You . The shooting script contains explicit scene description, camera set-ups that include angle and lens choices, dialog, and transitions - all the relevant instruction needed for anyone to reproduce the film with explicit similarity to its original. The thesis reflects a series of short videos I completed as research. In their finished state, the series of videos coalesce to a single film/video with a sixty-two-minute running time. That conglomeration emerged as a “shadow” or “inversion” of a twenty-minute, singlechannel video loop called Intermission For Deleted Acts, which served as centerpiece to my thesis exhibition. The script navigates themes of environmental catastrophe, companionship, survival, surveillance, and art practice. The following thesis attempts to keep the screenplay formatting intact to communicate both its functionality and aesthetic quality.

Hens were trained to peck a square stimulus on a touch-sensitive screen under an FR5 reinforcement schedule for a maximum of 30 reinforcers (taking approximately 10 minutes). Then hens experienced extinction sessions of 40 minutes duration. For a total of six conditions, reinforcement and extinction conditions were alternated. Each condition consisted of between approximately 7 and 10 sessions. Results show that structures developed during conditioning remain in extinction, at least for the duration of previous reinforcement sessions. After approximately 10 minutes, behaviour becomes more variable. There was also an absence of any 'extinction burst'. Extended extinction conditions, and alternating extinction conditions with reinforcement conditions had little effect on the variability of behaviour, but did influence the rate of responding. Responding persisted a little longer before gradually declining across sessions in the first extinction condition. In extinction conditions 2 and 3 responding tended to occur more as 'peaks'; short periods of increased responding with periods of non-responding between peaks.