Life Sciences Commons^™

Contributions Of Reward Identity And Time Prediction Errors To Pavlovian Learning, Daniel B. Siegel

Dissertations, Theses, and Capstone Projects

Some models of associative learning attempt to explain effects such as blocking and unblocking as reflecting a prediction error (PE): Associative strength, and thereby learning, are said to be greater when the unconditioned stimulus (US) received following a cue deviates from one’s expectations. Some models of PE-motivated behavior and PE-relevant brain activity represent the US as a single quantitative variable for outcome value, and that learning therefore only occurs when outcome value differs from expectations. There is growing evidence to suggest that changes in other dimensions of reward, such as identity and timing, also contribute to learning. In Experiment 1, …

Murine Genetic Variance In Sugar And Fat-Conditioned Flavor Preferences: Roles Of Dopamine, Opioid And Nmda Receptors And Nutritive Sensing, Tamar T. Kraft

Dissertations, Theses, and Capstone Projects

As obesity and diabetes have emerged as a severe public health crisis, understanding the mechanisms underlying the consumption of sugars and fats has become a topic of vigorous study. From a biological standpoint, genetic dispositions, neurochemical and hormonal influences, and predetermined orosensory and postingestive signals that modulate the hunger and satiety process may govern physiological aspects of the obesity puzzle. In addition to an innate appetite and attraction for simple carbohydrates and fats, learning plays an important role in modulating preferences for sugar- and fat-rich foods in rodents, including inbred mouse strains. Marked genetic variance has been observed among murine …

Structure And Function Of Dopamine In The Inner Ear And Auditory Efferent System Of A Vocal Fish, Jonathan T. Perelmuter

Dissertations, Theses, and Capstone Projects

The neuromodulator dopamine is considered essential for coordinating the internal motivational state of an organism with appropriate behavioral responses to stimuli in the external environment. This could be accomplished by modifying the function of neural circuits involved in sensory processing such that they are “tuned in” and optimally sensitive to important stimuli during critical time windows. While dopamine modulation of auditory processing has been studied in the central nervous system, neuromodulation can also occur outside the brain, in the inner ear. The majority of investigations of dopamine in the ear are conducted using rodents and focus on its role in …

Δ-9-Thc Effect On The Dopamine Transporter, Brooke E. Nielsen

Student Theses

Understanding the mechanism behind drugs of abuse is one of the key elements to understanding why addiction is so prevalent in society. The goal of this research was to determine the effect that a popular cannabinoid, Δ -9-tetrahydrocannabinol has on the regulation of dopamine neurotransmitter in the synapses. It was hypothesized that the addictive high users experience from using Δ-9-THC had a direct effect on lowering the dopamine transporter protein on cell surface causing a buildup of dopamine in the synapse. The results of the study show that the higher concentration of Δ-9-THC that the cells were exposed to caused …

The Nucleus Accumbens Core Dopamine D1 And Glutamate Ampa/Nmda Receptors Play A Transient Role In The Performance Of Pavlovian Approach Behavior, Veronica Dobrovitsky

Dissertations, Theses, and Capstone Projects

The role of the nucleus accumbens core (NAc core) continues to be redefined with newly acquired data on neurochemical mechanisms mediating the learning and performance of behavior. Previous empirical data showed that dopamine transmission at the D1 receptor (D1R) plays a transient role in the expression of learned Pavlovian approach behavior. Here we show that, prior to overtraining, dopamine activity at D1Rs specifically within the NAc core is critical for the performance of approach behavior elicited by the recently-acquired reward-paired cue. Blockade of D1Rs in the NAc core, but not the dorsomedial striatum or NAc shell, disrupted approach responses during …

Roles Of Dopamine D1 And D2, Opioid And Glutamate Nmda Receptor Signaling In The Acquisition And Expression Of Fat- And Glucose-Conditioned Flavor Preferences In Rats And C-Fos Analysis Of The Dopamine Mesotelencephalic And Nigrostriatal Pathways Following Intake Of Sugars And Fats In Rats, Julie Dela Cruz

Dissertations, Theses, and Capstone Projects

Systemic administration of the non-competitive NMDA antagonist, MK-801, demonstrated that acquisition, but not expression, were found to affect the orosensory-mediated (flavor/flavor: f/f) fructose-conditioned flavor preference (CFP). The present studies demonstrated a similar outcome when f/f and f/n processes were combined. Fat-CFP and glucose-CFP studies indicated that systemic injections of the NMDA antagonist, MK-801, were able to significantly reduce acquisition, but not expression, of Corn-Oil (CO)-CFP and glucose-CFP. Both studies appear to have mitigated effects on acquisition as compared to the separate orosensory and postingestive CFP studies.

Previous studies found that systemic administration of dopamine (DA) D1 (SCH23390) and D2 (raclopride) …