Title from first page of PDF document. Includes bibliographical references (p. 22-31).

This thesis will discuss Pavlovian conditioning and its utility in researching various areas of psychology including interpersonal attraction. It was designed to extend the application of conditioning principles in the study of interpersonal attraction by testing cue competition predictions made by the reinforcement-context theory of attraction.

Doctor of Philosophy / Psychological Sciences / Mary E. Cain / Gene-environment interactions play a significant role in drug abuse and addiction. Epigenetics (the study of how environmental stimuli alter gene expression) has gained attention in recent years as a significant contributor to many behavioral phenotypes of drug addiction. The current study sought to determine if differential rearing conditions can alter a specific epigenetic mechanism, histone deacetylase (HDAC), and how HDAC inhibition can affect drug-taking and drug-seeking behaviors differently among enriched, isolated, or standard-housed rats. Ninety male Sprague-Dawley rats were reared for 30 days in enriched (EC), isolated (IC), or standard (SC) conditions prior to amphetamine (0.03, 0.05, 0.1 mg/kg/infusion, i.v.) self-administration, extinction, or reinstatement sessions. Trichostatin A (TsA; 0.3 mg/kg, i.v.), an HDAC inhibitor, was injected 30 min prior to drug-taking or drug-seeking sessions. Results indicated that EC rats self-administered less amphetamine (0.03 mg/kg/infusion) than IC rats. No significant effects of TsA administration were found on general self-administration for any of the three amphetamine doses. While enrichment facilitated the extinction of active lever pressing, there was also a mild facilitation of extinction in IC-TsA rats compared to IC-vehicle counterparts. Lastly, TsA administration decreased cue-, but not drug-induced reinstatement, with IC-TsA rats exhibiting significantly attenuated cue-induced reinstatement compared to IC-vehicle rats. These findings suggest that differential rearing can alter HDAC mechanisms that can change drug-seeking behaviors, particularly in rats reared in isolated conditions. While TsA-induced HDAC inhibition may be less protective against general amphetamine self-administration, it may decrease drug-seeking tendencies during relapse that are induced by the reintroduction of contextual environmental cues heavily associated with drug reward.

Introduction Placebos have been used in medical treatments since the dawn of medicine. The placeboeffect is referred to as a beneficial effect of a treatment which cannot be attributed to thepharmacological component of the treatment given. Aim and Method We attempt to understand the current research regarding the placebo effect, its mechanismsand driving factors. We utilize hermeneutics, text-based analytics and argument analysis toanswer our ethical questions regarding the usage of placebo and the placebo effect. Results Classical conditioning and expectation have been accredited as the two most prominentfactors driving a placebo effect. Recent research focuses on identifying minor factorsinfluencing these prominent factors. Through modern imaging techniques researchers haveidentified physiological responses to the placebo effect.We pose four different ways in which a placebo treatment option could be considered ineveryday medicine. We also discuss whether the placebo effect should be used for itsbeneficial effects in all medical treatments, and how this could affect medicine and healthcarepractitioners. Conclusion Current research provides us with substantial evidence that the placebo effect has aphysiological component. It also provides us with explanations as to how this effect can beutilized in every day medical care. The placebo effect can even be utilized without deceivingthe patient which has always been the biggest argument against incorporating it in day to daymedicine. However, there is still lacking evidence of when a placebo effect can be utilized toits full potential which limits its current clinical applications.

Thesis (Ph. D.)--State University of New York at Binghamton, Department of Psychology, 2006. / Includes bibliographical references.

The honeybee is one of the model species in insect olfaction and its sense of smell is well studied. However, knowledge about the spectrum of odorants detectable to honeybees is limited. One class of odorants that has never been tested so far are the amino acids, which are important constituents of floral nectar. The experiments reported here were conducted in order to (1) determine if the odor of amino acids is detectable to honeybees (Apis mellifera), and (2) determine olfactory detection thresholds in honeybees for detectable amino acid odors. To this end, the proboscis extension reflex, a classical conditioning paradigm that takes advantage of the honeybee’s ability to build a robust association between an odor stimulus and a nectar reward, was used. The results demonstrate that five out of 20 amino acids presented at 100 mM were detectable. The honeybees’ median olfactory detection thresholds for these five amino acids are 12 mM for L-tyrosine and L-cysteine, 50 mM for L-asparagine and L-tryptophan, and 100 mM for L-proline. These threshold values are high in comparison to naturally occurring concentrations in floral nectar, and compared to threshold values obtained in vertebrate species. One possible explanation for these findings is that the size of the olfactory receptor repertoire of honeybees limits their olfactory capabilities in terms of detectability and sensitivity for the odor of amino acids

Alcohol research has shown that alcohol-related stimuli can disrupt behavioral control and attract more attention in alcohol drinkers. Stimuli typically used in tasks assessing these mechanisms are likely representative of an individual's history. Responses to visual stimuli that no longer closely resemble an individual's history may help shed light on whether these behaviors are due to classical conditioning or processes such as semantic priming. Hypotheses were tested using typical visual stimuli and modified, abstract versions in these tasks. 41 participants were exposed to these stimuli types while using a visual dot probe task. The difference in degree of attentional bias between real and modified stimuli was determined using gaze time. Individuals participated in two versions of the attentional bias-behavioral activation (ABBA) task. Proportion of inhibitory failure differences between versions was examined for the effects of stimuli modification on behavioral control. Results demonstrated that the sample did not exhibit an attentional bias to alcohol. Visual probe results yielded no differences between real and modified stimuli on attentional bias. ABBA performance indicated no differences as a result of image abstraction or stimuli type. Reasons for these findings and comparisons to similar research inquiries using the tasks the current thesis utilized were explored.

Delay classical eyeblink conditioning is an important model of associative, cerebellar dependent learning. Norepinephrine (NE) plays a significant modulatory role in the acquisition of learning; other neurotransmitter systems are also at play. The goal of this dissertation was to determine whether NE, GABA and glutamate (Glu) release is observed in cerebellar cortex during delay eye blink conditioning, and whether such release was selectively associated with training and not due only to stimulatory sensory input. The data support the hypothesis of noradrenergic and GABAergic system involvement in motor learning with NE as a modulator of early responding and GABA as a mediator of the learned response. In addition to neurotransmitter levels, we found that the local administration into the cerebellum of Rp-cAMP and propranolol impair the consolidation of learning when administered post training on the eyeblink conditioning task indicating that the B-adrenergic receptor and the cAMP downstream signaling cascade are essential for memory consolidation. These results support the hypothesis of NE acting as a neuromodulator in the cerebellum for the acquisition of motor learning. A similar experimental design was applied to aged animals and the neurochemical pattern of release was haracterized by a delay in the response to eyeblink conditioning and smaller amounts of the neurotransmitter evoked by the paired US-CS. It is hypothesized that the impairment in aging could be due to excitotoxicity caused by chronic inflammation. The present study also approached this issue by targeting the pro-inflammatory cytokine TNF-a and we found that suppression of TNF-a in aged animals improved learning.

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To survive, many biological organisms need to accurately infer which features of their environment predict future rewards and punishments. In machine learning terms, this is the problem of spatial credit assignment, for which many supervised learning algorithms have been developed. In this thesis, I mainly propose that a dual-pathway, regression-like strategy and associated biological implementations may be used to solve this problem. Using David Marr's (1982) three-level philosophy of computational neuroscience, the thesis and its contributions are organized as follows: - Computational Level: Here, the spatial credit assignment problem is formally defined and modeled using probability density functions. The specific challenges of the problem faced by organisms and machine learning algorithms alike are also identified. - Algorithmic Level: I present and evaluate the novel hypothesis that the general strategy used by animals is to perform a regression over past experiences. I also introduce an extension of a probabilistic model for regression that substantially improves generalization without resorting to regularization. This approach subdues residual associations to irrelevant features, as does regularization. - Physical Level: Here, the neuroscience of classical conditioning and of the basal ganglia is briefly reviewed. Then, two novel models of the basal ganglia are put forward: 1) an online-learning model that supports the regression hypothesis and 2) a biological implementation of the probabilistic model previously introduced. Finally, we compare these models to others in the literature. In short, this thesis establishes a theoretical framework for studying the spatial credit assignment problem, offers a simple hypothesis for how biological systems solve it, and implements basal ganglia-based algorithms in support. The thesis brings to light novel approaches for machine learning and several explanations for biological structures and classical conditioning phenomena. / Note: While the thesis contains content from two articles (one journal, one conference), their publishers do not require special permission for their use in dissertations (information confirming this is in an appendix of the thesis itself).