Behavioral Neurobiology Commons^™

Behavioral And Neural Microstructures Of Dynamic Cue-Motivated Responses, Erica Townsend

Dartmouth College Ph.D Dissertations

Sign-tracking, a conditioned response in which animals are physically attracted to reward-predictive cues due to motivational value attribution, is known to be persistent but can be flexible under some circumstances. For example, during an omission paradigm, in which vigorous responses must be withheld to avoid reward cancellation, animals can quickly restructure their responses. However, sign-tracking does not cease entirely, and cue attraction persists. This dissertation explores the behavioral and neural mechanisms underlying the simultaneous persistence and flexibility of sign-tracking during omission procedures. First, a novel method for behavioral analysis is introduced to accurately depict sign-tracking animals in dynamic tasks such …

Developing A Trial Unique Sequencing Task For Mice, Yader Gomez, Lilly Hagos, Gage Pompa, Ariana Mitic, Orlando Montiel, Talha Soluoku

Undergraduate Research Symposium Posters

The hippocampus and the anterior cingulate cortex (ACC) play distinct yet complimentary roles in the performance of cognitively demanding tasks.

While rodent models cannot truly capture human cognition, there is a serious need to develop more cognitively demanding rodent tasks to better understand human cognition to develop new tools to fight neurodegeneration.

Sequencing tasks are some of the most difficult for rodents to perform and are notoriously difficult to train.

Cutting edge interactive touch screen technology allows us to test an endless array of sequences, in a sound-controlled enclosure featuring a simple behavioral response for the mice.

Study Aim: To …

Characterizing The Medial Forebrain Bundle In Adolescents With Anhedonic Depression, Tina Nguyen

Biological Sciences Undergraduate Honors Theses

Adolescent depression has quickly grown in prevalence, yet the underlying neuropathology remains poorly understood. Anhedonia–the diminished ability to experience pleasure–is a core symptom of melancholic depression. Early identification of biomarkers associated with anhedonic depression could help mitigate the severity of the disorder by enhancing treatment efficacy. Blunted functionality of the nucleus accumbens (NAcc), the reward center of the brain, and abnormal dopaminergic activity in the ventral tegmental area (VTA) have both been linked to depression. Furthermore, glutamatergic input from the hypothalamus modulates the VTA which in turn, downregulates dopamine release in the NAcc. However, there is limited evidence supporting that …

Effects Of Social Isolation On Cecum Opioid Receptor Expression And Affective Behavior, Jordan Riser, John Tkaczynski, Nicole Shellenbarger, Maya Patel, Daniel Chandler, Daniel Manvich

Rowan-Virtua Research Day

BACKGROUND

Psychological stress can induce gastrointestinal symptoms and exacerbate existing gastrointestinal disorders, indicating an interaction between the central and enteric nervous systems. Central nervous system activation of opioid receptors stimulates sympathetic outflow to the enteric nervous system, delaying motility and reducing gastrointestinal secretions, producing a similar clinical presentation to IBS.

HYPOTHESIS

We hypothesize that social isolation induces anxiety states, disrupting homeostatic noradrenergic activity in the brain and gut, leading to neurophysiological changes in the cecum characterized by altered expression of opioid receptors.

METHODS

Sprague-Dawley rats were housed in either group (control) or socially isolated conditions. Affective behavior was assessed using …

Modulation Of Opioid Receptor Expression In The Ventral Tegmental Area Following Stress Exposure In Rats, Maya Patel, John Tkaczynski, Jordan Riser, Nicole Shellenbarger, Jin Park, Daniel Manvich, Daniel J. Chandler

Rowan-Virtua Research Day

Background: The ventral tegmental area (VTA) contains dopamine-producing neurons projecting to various brain regions. VTA dysfunction is linked to addiction and depression. Delta opioid receptor upregulation relates to chronic pain, inflammation, cancer, and early adversity. Kappa receptors in the VTA influence stress, drug-seeking, mood, and reward. Notably, chronic substance abuse upregulates the κ-receptor/dynorphin system, and the opioid system regulates social interaction needs.

Hypothesis: Stress will upregulate opioid receptors.

Methods: We compared group-housed and individually-housed rats using stress tests, analyzing behavior and quantifying VTA opioid receptor expression.

Results: Social isolation upregulated delta and kappa opioid receptors in …

A Neuroimmune Circuit Mediates Chemo Brain Pathology, Daniel Ahmadi

McKelvey School of Engineering Graduate Student Theses & Dissertations

Chemotherapeutic agents, while effective in targeting malignant tumors, often reduce the patients’ quality of life by inducing fatigue, pain, and motivational deficits. These symptoms are collectively referred to as “chemo brain.” The mechanisms underlying these adverse effects, and specifically whether fatigue and motivational impairments share a common etiology, remain poorly understood. The neural–immune substrates of these symptoms remain obscure, in part because standard preclinical regimens either bypass key systemic signals or introduce local toxicity confounds. Here, I establish and validate a three‑day, low‑dose intravenous cisplatin protocol that avoids peritoneal inflammation and severe renal injury yet produces robust, reversible fatigue and …

Mechanisms Of Behavioral Change In Hosts Of Toxoplasma Gondii: A Review, Olivia Grimsley

Senior Honors Theses

The parasite Toxoplasma gondii is a highly ubiquitous parasite that latently infects an estimated 33% percent of the global population. Toxoplasmosis is of obvious clinical significance due to the extremely high risks to the unborn who contract it congenitally. Less attention has been given to a more subtle aspect of latent infection, which is the behavioral alterations that are commonly experienced by those who contract the parasite. Infected individuals commonly display a variety of altered behaviors, such as increased aggression and risk-seeking behaviors, depression, higher tendency towards suicide and self-directed violence, a loss of fear response, and a greatly increased …

Investigating Prefrontal Cortex Neuronal Signatures Of Opioid-Induced Risk-Taking Behavior, Cana Quave

Dissertations and Theses (Open Access)

Opioid use disorder occurs alongside impaired risk-related decision-making, but the underlying neural correlates are unclear. We developed an approach-avoidance conflict task using a modified conditioned place preference procedure to study neural signals of risky opioid seeking in the prefrontal cortex, a region implicated in executive decision-making. Following morphine conditioned place preference, rats underwent a conflict test in which fear-inducing cat odor was introduced in the previously drug-paired side of the apparatus. While the saline-exposed control group avoided cat odor, the morphine group included two subsets of rats that either maintained a preference for the paired side despite the presence of …

Neural Activity Within And Between Visual And Executive Areas Is Modulated Post-Locomotion In Rhesus Macaques, Sergey Egranov

Dissertations and Theses (Open Access)

Physical activity has been shown to benefit cognitive and mental health by improving cerebrovascular perfusion and regulating hormone-mediated processes on a systemic level. However, the acute effects of physical activity, such as locomotion, on the neuronal circuits underlying cognitive processes have yet to be fully characterized. This body of work seeks to rectify this gap in knowledge through analysis of how both behavioral performance and neuronal activity signatures in visual and executive brain regions are modulated post-locomotion in rhesus macaques.

To this end, we performed high-yield electrophysiological recordings simultaneously from area V4, a mid-tier visual cortical region, and the dorsolateral …

Investigating The Role Of The Hypocretin/Orexin System In A Novel Model Of Polysubstance Dependence, Tyler Zarin

Electronic Theses and Dissertations

Substance use disorders (SUD) in the United States are steadily increasing. Potent and dangerous substances such as methamphetamine (MA) and fentanyl (FEN) are often co-used as a polysubstance (POLY), either intentionally or unknowingly as FEN is a common adulterant. SUD is characterized by physiological and psychological dependence involving the negative reinforcement of anhedonia and withdrawal which drive hypermotivated drug-taking behaviors. Current theory suggests that recruitment of hypocretin/orexin (HCRT) neuropeptide in reward and stress associated brain regions contributes to drug dependence. Despite strong evidence for HCRT’s role in mono-drug dependence, a relevant model for POLY dependence has yet to be developed, …

Assessing The Behavioral Impact Of Pyridostigmine Bromide In Rats, Noah A. Martin

Honors Theses

Pyridostigmine bromide (PB) is an organophosphate (OP) nerve agent prophylactic used to protect warfighters against chemical warfare agents. OPs inhibit the neural enzyme acetylcholinesterase (AChE) in the brain. This leads to the buildup of acetylcholine, causing respiratory failure, seizures, and death. PB functions by inhibiting ~30% of peripheral AChE temporarily, protecting the enzymes so that the body is able to restore sufficient cholinergic function post-exposure. PB does not cross the blood-brain barrier, though it may still indirectly affect toxicity in the brain due to repeated AChE inhibition throughout treatment, or by inhibition of non-target ChE’s in the blood. The aim …

A Natural Short Sleep Mutation Promotes Longevity Through Mitochondrial Respiration In Drosophila, Pritika Pandey

LSU Doctoral Dissertations

Aging is an irreversible process characterized by progressive physiological decline and an increased risk of metabolic disorders, cognitive impairment, cardiovascular diseases, and neurodegeneration. Disruptions to the circadian clock—whether due to genetic mutations or behavioral factors—accelerate aging and age-related pathologies, highlighting a strong link between circadian regulation and longevity. However, certain individuals harbor a dec2^P384R mutation, which enables natural short sleep without the detrimental effects of chronic sleep deprivation. This suggests that these individuals have evolved adaptations that activate pro-health pathways, allowing them to function optimally with reduced sleep. To investigate the genetic mechanisms underlying these changes, we developed a …

How Childhood Maltreatment Shapes Brain Regions: Considerations For Speech-Language Pathology, Alexa G. Sees

Honors Thesis

Childhood maltreatment is a pervasive issue that affects millions of children worldwide, leading to alterations in key structures such as the limbic system, basal ganglia, corpus callosum, visual cortex, and language areas. These changes result in significant cognitive, emotional, and neurological consequences, such as learning deficits, emotional regulation issues, memory problems, reduced vocabulary size, speech errors, etc. This thesis explores the neurological effects of childhood maltreatment and their implications for speech-language pathology, highlighting how maltreatment-induced brain changes affect areas within the scope of speech-language pathology, such as social communication, language development, and behavior management. These results underscore the importance of …

Psilocybin Impairs The Extinction Of Contextual Fear In Adult Female, But Not Male, Rats, Lillianna P. Puppel, Aleece K. Al-Olimat, Kylie M. King, Marisa J. Savini, Claire E. Miller, Colin R. Del Valle, Heather R. Sparkman, Brooke E. Bramlage, Phillip R. Zoladz

ONU Student Research Colloquium

Fear-related disorders are often treated with exposure therapy, a technique based on the concept of extinction. However, this type of therapy is ineffective for many individuals, so finding a pharmacological adjunct that augments the extinction of fear could lead to better treatment outcomes. In recent preclinical work, investigators have shown that psychedelics can accelerate the extinction of fear, potentially through their impact on neurotrophic signaling. We previously found that psilocybin exerted sex-dependent effects on the extinction of conditioned fear to an isolated cue (i.e., a tone). Specifically, psilocybin enhanced the extinction of cue fear in male rats but impaired it …

The Role Of Cholinergic Ventral Pallidum Cells In Effortful Motivation, Elizabeth A. Bien

Dartmouth College Ph.D Dissertations

Maladaptive reward-seeking behavior can be driven by one of several different components including excessive craving elicited by cues that predict rewards, failing to effortfully pursue rewards when it is beneficial to do so, and compulsively seeking rewards when it is no longer advantageous to do so. This thesis includes experiments focusing on these three different components of reward-seeking behavior to better understand how reward-seeking can become maladaptive. First, we wanted to examine the role that sex plays in the acquisition and compulsiveness of sign-tracking behavior in the Long Evans rat, a strain that is commonly used as the background for …

Individual Differences In The Effects Of A Muscarinic Antagonist On Cued Fear Recall And Extinction, Caitlyn J. White

Senior Theses

Post-Traumatic Stress Disorder (PTSD) is characterized by an inability to extinguish fear after experiencing a traumatic event. The cholinergic system shows increased activity during fear learning and extinction, suggesting a role for cholinergic transmission in PTSD. Our lab has previously found that rats can be divided into extinction resistant (ER) and extinction competent (EC) phenotypes, with ER representing a PTSD-like phenotype. While women are more likely to develop PTSD, there is limited literature on the cholinergic system and recall of cued fear or extinction in female rats which are used as a model system due to their similar brain anatomy. …

Effects Of Social Isolation On Locus Coeruleus Opioid Receptor Expression And Affective Behavior, John Tkaczynski, Jordan Riser, Maya Patel, Nicole Shellenbarger, Jin Park, Daniel Manvich, Daniel J Chandler

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Social isolation is a stressor that impairs homeostatic neuroendocrine functions and is associated with the development of several mood disorders characterized by persistent negative affect. Persistent feelings of loneliness have been growing public health concerns for several years and were greatly exacerbated by the onset of the COVID-19 pandemic. The problem has grown so severe the U.S. Surgeon General recently declared loneliness to be an epidemic health concern that is associated with poor mental and somatic health outcomes. Therefore, identifying mechanisms of neuroadaptation that contribute to the development of persistent negative affect is a critical step in the identifying better …

Impact Of Acute Stress On Circadian Rhythm Regulation Of Locomotor Activity In Syrian Hamsters, Raquel A. Villarreal, Laura E. Garcia, Mario Gil

Research Symposium

Background: Disruptions of circadian rhythms, caused by factors such as environmental changes or stress, are linked to health conditions, including metabolic disorders, cardiovascular diseases, and mood disorders. Circadian rhythm disturbances are particularly relevant for understanding the etiology of conditions like insomnia, depression, and anxiety. The circadian rhythm, primarily regulated by the suprachiasmatic nuclei (SCN) in the hypothalamus, coordinates biological processes to align with daily environmental cycles. Acute stress, especially when experienced immediately upon waking, has been shown to disrupt these rhythms, impair sleep regulation, and exacerbate mood dysregulation. Given the significant clinical implications, understanding how stress impacts circadian rhythms is …

The Role Of The Female Reproductive Cycle In Social Communication And Relevance To Mental Health, Julissa Amaro Castillo, Fernando Dominguez, Ariana Hinojosa, Giselle Padilla, Mario Gil

Research Symposium

The female reproductive cycle is characterized by fluctuating hormones, including estrogens and progesterone, that are involved in reproductive health; however, they have also been linked to disorders like Premenstrual syndrome (PMS), Premenstrual Dysphoric Disorder (PMDD), mood swings, depression and others. The goal of this study is to use the Syrian hamster (Mesocricetus auratus) as an animal model to examine the influence of the reproductive cycle and hormones on behavior. Scent-marking activity known as flank marking is exhibited by territorial or sociable animals. In essence, animals mark their territory or convey information such as reproductive status by rubbing their flanks or …

Effects Of Arginine-Vasopressin In The Brain On Cardiovascular Function In A Psychosocial Stress Animal Model, Esmeralda Lopez-Garcia, Ariana V. Hinojosa, Esperanza I. Alaniz, Fernando Dominguez, Giselle Padilla, Mario Gil

Research Symposium

Background: Psychosocial stress impacts cardiovascular health, increasing the risk of events like myocardial infarction (MI), stress cardiomyopathy, and neuropsychiatric disorders, including Major Depressive Disorder (MDD) and Anxiety. However, our understanding of the biological mechanisms that connect psychosocial stress with negative cardiovascular and psychological outcomes remains incomplete. Arginine-vasopressin (AVP) is linked to both mental and physical health by regulating social behavior, blood pressure, and anxiety-related behaviors. This study investigates the potential cardioprotective effects of the neuropeptide AVP, in an effort to generate evidence that it may strengthen heart function and lessen the severity of adverse cardiovascular events caused by stress, brain …