Medicine and Health Sciences Commons^™

The Impact Of Social Isolation On The Neural Pathways Of Dopamine Neurons In The Ventral Tegmental Area (Vta) And The Nucelus Accumbens (Nac): Implications For The Treatment Of Depression, Anxiety, And Drug Addiction., Cristian M. Botello, Sasawan Heingraj, John L. Vandeberg, Mario Gil

Research Symposium

As the literature on the Monodelphis domestica continues to grow, it is important to contribute to the knowledge base regarding neural pathways and their role in social behavior in this species. Previous studies have provided evidence that increased activity in ventral tegmental area (VTA) dopamine neurons were associated with more social activity in mice. It is also known that in traditional rodent models, the Nucleus Accumbens (NAcc) is implicated in interaction reward processes like motivation; however, more research is needed to elucidate the role of the NAcc in social behavior of the M. domestica. The present study was designed …

L-Theanine Prevents Long-Term Affective And Cognitive Side Effects Of Adolescent Δ-9-Tetrahydrocannabinol Exposure And Blocks Associated Molecular And Neuronal Abnormalities In The Mesocorticolimbic Circuitry, Marta De Felice, Justine Renard, Roger Hudson, Hanna J. Szkudlarek, Brian J. Pereira, Susanne Schmid, Walter J. Rushlow, Steven R. Laviolette

Brain and Mind Institute Researchers' Publications

Chronic adolescent exposure to Δ-9-tetrahydrocannabinol (THC) is linked to elevated neuropsychiatric risk and induces neuronal, molecular and behavioral abnormalities resembling neuropsychiatric endophenotypes. Previous evidence has revealed that the mesocorticolimbic circuitry, including the prefrontal cortex (PFC) and mesolimbic dopamine (DA) pathway are particularly susceptible to THC-induced pathologic alterations, including dysregulation of DAergic activity states, loss of PFC GABAergic inhibitory control and affective and cognitive abnormalities. There are currently limited pharmacological intervention strategies capable of preventing THC-induced neuropathological adaptations. L-Theanine is an amino acid analog of L-glutamate and L-glutamine derived from various plant sources, including green tea leaves. L-Theanine has previously been …

The Impact Of Levodopa Administration On Learning From Short-Term And Long-Term Action Consequences: A Paradigm Validation., Masood Rezaei

Electronic Thesis and Dissertation Repository

Behavioral and neuroimaging studies have identified two valuation systems in the human brain for controlling behavior known as model-free (MF) and model-based (MB). MF is based on immediate evaluation and MB is based on long-term evaluation of the outcome of our decisions. Previous studies suggest that dopamine baseline activity may play an important role in the balance between the two systems and determine how they compete or interact in controlling our actions. The overarching aims of this study is to investigate the impact of levodopa administration on learning from immediate and long-term action consequences, and to dissociate the role of …

The Role Of Dopamine In Decision Making Processes In Drosophila Melanogaster, Michelle C. Bowers

Undergraduate Honors Theses

Understanding the neural processes that mediate decision making is a relatively new field of investigation in the scientific community. With the ultimate goal of understanding how humans decide between one path and another, simpler models such as Drosophila Melanogaster, the common fruit fly, are often utilized as a way of determining the neural circuits involved in these decision-making processes. One of the most important decisions flies make is the decision of where to lay their eggs (oviposit). Choosing the proper substrate upon which to lay eggs is a crucial decision that can ultimately impact their fecundity. This paper investigates the …

Dorsal Striatum Does Not Mediate Feedback-Based, Stimulus-Response Learning: An Event-Related Fmri Study In Patients With Parkinson's Disease Tested On And Off Dopaminergic Therapy, Nole M. Hiebert, Adrian M. Owen, Hooman Ganjavi, Daniel Mendonça, Mary E. Jenkins, Ken N. Seergobin, Penny A. Macdonald

Brain and Mind Institute Researchers' Publications

© 2018 Learning associations between stimuli and responses is essential to everyday life. Dorsal striatum (DS) has long been implicated in stimulus-response learning, though recent results challenge this contention. We have proposed that discrepant findings arise because stimulus-response learning methodology generally confounds learning and response selection processes. In 19 patients with Parkinson's disease (PD) and 18 age-matched controls, we found that dopaminergic therapy decreased the efficiency of stimulus-response learning, with corresponding attenuation of ventral striatum (VS) activation. In contrast, exogenous dopamine improved response selection accuracy related to enhanced DS BOLD signal. Contrasts between PD patients and controls fully support these …

Translational Tests Involving Non-Reward: Methodological Considerations, Benjamin U. Phillips, Laura Lopez-Cruz, Lisa M. Saksida, Timothy J. Bussey

Brain and Mind Institute Researchers' Publications

© 2018, The Author(s). This review is concerned with methods for assessing the processing of unrewarded responses in experimental animals and the mechanisms underlying performance of these tasks. A number of clinical populations, including Parkinson’s disease, depression, compulsive disorders, and schizophrenia demonstrate either abnormal processing or learning from non-rewarded responses in laboratory-based reinforcement learning tasks. These effects are hypothesized to result from disturbances in modulatory neurotransmitter systems, including dopamine and serotonin. Parallel work in experimental animals has revealed consistent behavioral patterns associated with non-reward and, consistent with the human literature, modulatory roles for specific neurotransmitters. Classical tests involving an important …

When Brain Stimulation Backfires, Sarah Beth Bell

Theses and Dissertations--Psychology

tDCS brain stimulation does not always work in the intended direction. It has been found to sometimes worsen behavior rather than improve it. A preliminary study shows that people high on sensation-seeking and lack of premeditation were prone to reverse effects of tDCS on performance on a Stop Signal Task. Both of these constructs are related to dopamine levels. Study 2 seeks to intentionally cause a reverse effect of tDCS by increasing participants’ dopamine levels via caffeine. There was not a significant interaction between tDCS and caffeine on errors on the Stop Signal Task in this study. However, other factors …

Effort-Related Decision Making In Comt Variant Mice: Pharmacological Studies And Genetic Susceptibility To Motivational Dysfunction, Suzanne Cayer

Honors Scholar Theses

Effort-related decision making tasks in animals can model motivational symptoms in humans, which are a set of symptoms spanning a multitude of neuropsychiatric disorders, such as major depressive disorder and the negative symptoms of schizophrenia. The present studies aimed to evaluate the effort-related effects of the Val158Met polymorphism of human catechol-methyltransferase (COMT), by testing mice carrying either the human COMT Val (n=8) or Met allele (n=8) with Wild-Type control mice (n=15) by using concurrent FR2 and FR4/pellet choice tasks in a touchscreen operant conditioning apparatus. The Val158Met polymorphism has been repeatedly associated with neuropsychiatric disorders, and the Val allele has …

Possible Breakdown Of Dopamine Receptor Synergism In A Mouse Model Of Huntington's Disease, Samantha F. Kennedy

University of New Orleans Theses and Dissertations

The model of basal ganglia function proposed by Albin, Young and Penney (1989) describes two anatomically independent motor pathways, the direct and indirect. However, under normal conditions striatal dopamine (DA) is required for the expression of motor behavior, and DAergic control of the two pathways (via D1 and D2 receptors, respectively) is dependent on co-activation. We tested for a possible breakdown of D1/D2 synergism using transgenic R6/1 mice bearing the human huntingtin allele (Htt). Motor stereotypy, observed prior to the onset of HD-related symptoms, was rated on a 5-point scale following activation of: A) D1 receptors alone, B) D2 receptors …

Adolescent Cannabinoid Exposure Induces A Persistent Sub-Cortical Hyper-Dopaminergic State And Associated Molecular Adaptations In The Prefrontal Cortex., Justine Renard, Laura G Rosen, Michael Loureiro, Cleusa De Oliveira, Susanne Schmid, Walter J Rushlow, Steven R Laviolette

Brain and Mind Institute Researchers' Publications

Considerable evidence suggests that adolescent exposure to delta-9-tetrahydrocanabinol (THC), the psychoactive component in marijuana, increases the risk of developing schizophrenia-related symptoms in early adulthood. In the present study, we used a combination of behavioral and molecular analyses with in vivo neuronal electrophysiology to compare the long-term effects of adolescent versus adulthood THC exposure in rats. We report that adolescent, but not adult, THC exposure induces long-term neuropsychiatric-like phenotypes similar to those observed in clinical populations. Thus, adolescent THC exposure induced behavioral abnormalities resembling positive and negative schizophrenia-related endophenotypes and a state of neuronal hyperactivity in the mesocorticolimbic dopamine (DA) pathway. …

The Effect Of Gaba A Antagonism On Locomotor Activity And Dopamine Release In The Mouse Caudate Putamen Following Acute Toluene Inhalation: An In-Vivo Microdialysis Study, Sean Callan

Wayne State University Theses

Toluene is ubiquitous solvent commonly inhaled recreationally. Despite its frequency of misuse, there is little understanding of how toluene acts within the brain. To examine this, this master's thesis examined the impact of acutely inhaled toluene on dopamine (DA) release in the mouse CPu in vivo using microdialysis techniques. Toluene inhalation produced dose-dependent increases in DA levels as well as changes in locomotor activity. These effects were potentiated by pre-treatment with the GABAA antagonist bicuculline via reverse microdialysis delivery. These results suggest that the DA dynamics of toluene abuse are related to toluene's previously explored effects on the GABA system. …

Dopaminergic Medication Impairs Feedback-Based Stimulus-Response Learning But Not Response Selection In Parkinson's Disease., Andrew Vo, Nole M Hiebert, Ken N Seergobin, Stephanie Solcz, Allison Partridge, Penny A Macdonald

Brain and Mind Institute Researchers' Publications

Cognitive dysfunction is a feature of Parkinson's Disease (PD). Some cognitive functions are impaired by dopaminergic medications prescribed to address the movement symptoms that typify PD. Learning appears to be the cognitive function most frequently worsened by dopaminergic therapy. However, this result could reflect either impairments in learning (i.e., acquisition of associations among stimuli, responses, and outcomes) or deficits in performance based on learning (e.g., selecting responses). We sought to clarify the specific effects of dopaminergic medication on (a) stimulus-response association learning from outcome feedback and (b) response selection based on learning, in PD. We tested 28 PD patients on …

Differential Effects Of Parkinson's Disease And Dopamine Replacement On Memory Encoding And Retrieval., Alex A Macdonald, Ken N Seergobin, Adrian M Owen, Ruzbeh Tamjeedi, Oury Monchi, Hooman Ganjavi, Penny A Macdonald

Brain and Mind Institute Researchers' Publications

Increasingly memory deficits are recognized in Parkinson's disease (PD). In PD, the dopamine-producing cells of the substantia nigra (SN) are significantly degenerated whereas those in the ventral tegmental area (VTA) are relatively spared. Dopamine-replacement medication improves cognitive processes that implicate the SN-innervated dorsal striatum but is thought to impair those that depend upon the VTA-supplied ventral striatum, limbic and prefrontal cortices. Our aim was to examine memory encoding and retrieval in PD and how they are affected by dopamine replacement. Twenty-nine PD patients performed the Rey Auditory Verbal Learning Test (RAVLT) and a non-verbal analogue, the Aggie Figures Learning Test …

Effects Of Restraint Stress And Allopregnanolone Inhibition On Amphetamine Locomotor Sensitivity, Kelly Abuali, Laurel M. Pritchard

McNair Poster Presentations

The chronic, recurring nature of addiction remains a worldwide problem. Even after apparently successful clinical treatment and long term abstinence, individuals may still relapse many months or years later. Although many individual differences exist among substance abusers, relapse tends to occur during periods of high stress (Sinha et al., 2006). Behavioral training and therapy can help cope during these high stress times, but pharmacological interventions have not been shown to be effective (Ross & Peselow, 2009). Although some therapeutic options decrease relapse rates, more effective treatments for relapse need further consideration.

The effect of stress on use of and relapse …

Using Negative Feedback To Guide Behavior: Impairments On The Wisconsin Card Sorting Test Relates To Psychosis, Sally Barney

UNLV Theses, Dissertations, Professional Papers, and Capstones

There is increasing controversy regarding the distinction between schizophrenia and bipolar disorder as separate diagnostic categories because these disorders share many features in common. These and other findings suggest that bipolar disorder and schizophrenia may be better conceptualized along a continuum or within more homogeneous subsets of affective, psychotic, and mixed symptomatology.

Dopamine dysregulation has been found in schizophrenia and bipolar disorder, particularly those that experience psychosis during the acute phases of their bipolar illness. Dopamine has been found to play a role in reward and reward learning. Recently, research has found that individuals with schizophrenia experience deficits in reward …

Sex Differences In The Dopaminergic Regulation Of Courtship, But Not Pairing Behaviors In Zebra Finches, Erin Marie Lowrey

Wayne State University Theses

Dopamine is one of the key ingredients in the glue that cements social bonds in vertebrates. The D2 dopamine receptor has been implicated in the regulation of monogamous pair bonding in the prairie vole. While dopamine affects courtship behaviors in the male zebra finch, the behavioral role of dopamine acting at D2 receptors in both males and females deserves further attention. We hypothesized that the D2 receptor would regulate courtship and pairing behaviors in the male and female zebra finch. Sixteen males and females were tested using a repeated measures design. On day 1, the zebra finches were injected with …

The Role Of Dopamine In Resistance To Change Of Operant Behavior, Stacey L. Quick

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Psychological disorders such as autism, obsessive-compulsive disorder, drug addiction, and attention-deficit/hyperactivity disorder involve atypically persistent behavior and atypical activity of the neurotransmitter dopamine. Behavioral momentum theory states that the persistence of behavior in a context is determined by the reinforcement received previously in that context. Contexts previously associated with higher rates of reinforcement yield greater persistence of behavior than contexts previously associated with lower rates of reinforcement. According to a prominent hypothesis in behavioral neuroscience, dopamine mediates the incentive salience of a stimulus. A synthesis of behavioral momentum theory and the incentive salience hypothesis proposes similar roles for dopamine activity …

Comparison Of Affective Analgesia And Conditioned Place Preference Following Cholinergic Activation Of, Elena Schifirnet

Wayne State University Dissertations

Activation of the dopaminergic mesolimbic reward circuitry that originates in the ventral tegmental area (VTA) is postulated to preferentially suppress affective reactions to noxious stimuli (affective analgesia, AA). VTA dopamine neurons are activated via cholinergic inputs, and we have observed that microinjections of the acetylcholine agonist carbachol suppressed vocalizations of rats that occur following administration of brief (1 sec) tail-shocks (vocalization afterdischarges = VAD). VADs are a validated rodent model of pain affect. In addition, the capacity of carbachol to support reinforcement appears to be regionally dependent within VTA. Ikemoto and Wise (2002) reported that carbachol was self-administered in the …