Neuroscience and Neurobiology Commons^™

The Effects Of Chronic Simvastatin Treatment On The Expression Of Behavioral Symptoms In A Transgenic Mouse Model Of Huntington’S Disease, Ashley Whitmarsh

University of New Orleans Theses and Dissertations

Huntington’s disease (HD) is a heritable, neurodegenerative disorder characterized by motor, cognitive, and psychiatric disturbances. An unstable CAG expansion within the gene normally encoding for the Huntingtin protein is responsible. The expanded mutant form of Huntingtin and the putative protein co-factor Rhes interact and cause cell death within the striatum. We hypothesized chronic treatment with simvastatin, a cholesterol lowering drug, would disrupt the biosynthetical pathway which gives both Rhes and its target cells binding sites and render Rhes inactive. Healthy and HD mice were treated with simvastatin or a vehicle. Animals’ motor behavior was assessed with three separate tests over …

Enrichment And Training Improve Cognition In Rats With Cortical Malformations, Kyle R. Jenks, Marcella M. Lucas, Ben A. Duffy, Ashlee A. Robbins, Barjor Gimi, Jeremy M. Barry, Rod C. Scott

Dartmouth Scholarship

Children with malformations of cortical development (MCD) frequently have associated cognitive impairments which reduce quality of life. We hypothesized that cognitive deficits associated with MCD can be improved with environmental manipulation or additional training. The E17 methylazoxymethanol acetate (MAM) exposure model bears many anatomical hallmarks seen in human MCDs as well as similar behavioral and cognitive deficits. We divided control and MAM exposed Sprague-Dawley rats into enriched and non-enriched groups and tested performance in the Morris water maze. Another group similarly divided underwent sociability testing and also underwent Magnetic Resonance Imaging (MRI) scans pre and post enrichment. A third group …

Neural Responses During Trace Conditioning With Face And Non-Face Stimuli Recorded With Magnetoencephalography, Nicholas Lee Balderston

Theses and Dissertations

During fear conditioning a subject is presented with an initially innocuous stimulus like an image (conditioned stimulus; CS) that predicts an aversive outcome like a mild electric shock (unconditioned stimulus; UCS). Subjects rapidly learn that the CS predicts the UCS, and show autonomic fear responses (CRs) during the presentation of the CS. When the CS and the UCS coterminate, as is the case for delay conditioning, individuals can acquire CRs even if they are unable to predict the occurrence of the UCS. However when there is a temporal gap between the CS and the UCS, CR expression is typically dependent …

The Role Of The Amygdala, Retrosplenial Cortex, And Medial Prefrontal Cortex In Trace Fear Extinction And Reconsolidation, Janine Lynn Kwapis

Theses and Dissertations

A wealth of research has outlined the neural circuits responsible for the consolidation, reconsolidation, and extinction of standard "delay" fear conditioning, in which awareness is not required for learning. Far less is understood about the neural circuit supporting more complex, explicit associations. "Trace" fear conditioning is considered to be a rodent model of explicit fear because it relies on the cortex and hippocampus and requires explicit contingency awareness in humans for successful acquisition. In the current set of studies, we aimed to better characterize the neural circuit supporting the consolidation, reconsolidation, and extinction of trace fear in order to better …

Iptakalim Attenuates Self-Administration And Acquired Goal-Tracking Behavior Controlled By Nicotine, S. Charntikov, N. Swalve, Steven T. Pittenger, K. Fink, S. Schepers, G. C. Hadlock, A. E. Fleckenstein, G. Hu, Ming Li, Rick A. Bevins

Department of Psychology: Faculty Publications

Iptakalim is an ATP-sensitive potassium channel opener, as well as an a4b2-containing nicotinic acetylcholine receptor (nAChR) antagonist. Pretreatment with iptakalim diminishes nicotine-induced dopamine (DA) and glutamate release in the nucleus accumbens. This neuropharmacological profile suggests that iptakalim may be useful for treatment of nicotine dependence. Thus, we examined the effects of iptakalim in two preclinical models. First, the impact of iptakalim on the interoceptive stimulus effect of nicotine was evaluated by training rats in a discriminated goal-tracking task that included intermixed nicotine (0.4 mg/kg, SC) and saline sessions. Sucrose was intermittently presented in a responseindependent manner only on nicotine sessions. …

Repeated Asenapine Treatment Produces A Sensitization Effect In Two Preclinical Tests Of Antipsychotic Activity, Rongyin Qin, Yingzhu Chen, Ming Li

Department of Psychology: Faculty Publications

Among several commonly used atypical antipsychotic drugs, olanzapine and risperidone cause a sensitization effect in the conditioned avoidance response (CAR) and phencyclidine (PCP)- induced hyperlocomotion paradigms – two well established animal tests of antipsychotic drugs, whereas clozapine causes a tolerance effect. Asenapine is a novel antipsychotic drug recently approved for the treatment of schizophrenia and manic disorders. It shares several receptor binding sites and behavioral features with other atypical antipsychotic drugs. However, it is not clear what type of repeated effect (sensitization or tolerance) asenapine would induce, and whether such an effect is transferrable to other atypicals. In this study, …

Socially Excluded Individuals Fail To Recruit Medial Prefrontal Cortex For Negative Social Scenes, Katherine E. Powers, Dylan D. Wagner, Catherine J. Norris, Todd F. Heatherton

Dartmouth Scholarship

Converging behavioral evidence suggests that people respond to experiences of social exclusion with both defensive and affiliative strategies, allowing them to avoid further distress while also encouraging re-establishment of positive social connections. However, there are unresolved questions regarding the cognitive mechanisms underlying people's responses to social exclusion. Here, we sought to gain insight into these behavioral tendencies by using functional magnetic resonance imaging (fMRI) to examine the impact of social exclusion on neural responses to visual scenes that varied on dimensions of sociality and emotional valence. Compared to socially included participants, socially excluded participants failed to recruit dorsomedial prefrontal cortex …

Metergoline, The Basolateral Amygdala And The Ventral Pallidum: Implications For Panic Disorder, Douglas Ryan Schuweiler

Theses and Dissertations

Panic disorder (PD) is a common mental illness characterized by recurring spontaneous panic attacks. Scientific investigation into PD has been accelerated by the development of rat models of PD. These models can be validated by responses to intravenous sodium lactate (NaLac), including tachycardia, that are similar to PD patient responses. Previous work on established PD models has suggested that antagonism of serotonin (5-HT) receptors in the basolateral amygdala (BLA) may be sufficient to model PD. To test this hypothesis metergoline (MET), a 5-HT receptor antagonist, or vehicle was microinjected into the BLA of anesthetized rats. Following the microinjection, NaLac or …

Moral Dilemma Judgment Revisited: A Loreta Analysis, Armando F. Rocha, Fábiot T. Rocha, Eduardo Massad

Armando F Rocha

Recent neuroscience investigations on moral judgment have provided useful information about how brain processes such complex decision making. All these studies so were fMRI investigations and therefore constrained by the poor resolution of this technique. Recent advances in electroencephalography (EEG) analysis provided by Low Resolution Tomogray (Loreta), Principal Component (PCA), Correlation and Regression Analysis improved EEG spatial resolution and make EEG a very useful technique in decision-making studies. Here, we reinvestigate previously fMRI study of personal (PD) and impersonal (ID) moral dilemma judgment, taking profit of these new EEG analysis improvements. Compared to the previous fMRI results, Loreta and PCA …

Is Pressure Stressful? The Impact Of Pressure On The Stress Response And Category Learning, Shannon L. Mccoy, Steven B. Hutchinson, Lauren Hawthorne, Brandon J. Cosley, Shawn W. Ell

Psychology Faculty Scholarship

We examine the basic question of whether pressure is stressful. We propose that when examining the role of stress or pressure in cognitive performance it is important to consider the type of pressure, the stress response, and the aspect of cognition assessed. In Experiment 1, outcome pressure was not experienced as stressful but did lead to impaired performance on a rule-based (RB) category learning task and not a more procedural information-integration (II) task. In Experiment 2, the addition of monitoring pressure resulted in a modest stress response to combined pressure and impairment on both tasks. Across experiments, higher stress appraisals …

Social Compass Curriculum: Three Descriptive Case Studies Of Social Skills Outcomes For Students With Autism, Louanne E. Boyd, Deborah M. Ward

Engineering Faculty Articles and Research

The Social Compass Curriculum (SCC) was investigated for its effectiveness in improving core social skills in three descriptive case studies of students with autism. Treatment fidelity of the SCC was also measured in the school setting. The Social Responsiveness Scale and the Autism Social Skills Profile were completed by parents to measure pre- and postintervention social skills for three students aged 8 to 11 years who participated in the present multisite pilot study. Fidelity of implementation data were collected via a checklist during observations for three educators who implemented the intervention. Results indicate that the SCC improved core social deficits …

Day-Night Differences In Neural Activation In Histaminergic And Serotonergic Areas With Putative Projections To The Cerebrospinal Fluid In A Diurnal Brain, Alexandra Castillo-Ruiz, Andrew J. Gall, Laura Smale, Antonio A. Nunez

Faculty Publications

In nocturnal rodents, brain areas that promote wakefulness have a circadian pattern of neural activation that mirrors the sleep/wake cycle, with more neural activation during the active phase than during the rest phase. To investigate whether differences in temporal patterns of neural activity in wake-promoting regions contribute to differences in daily patterns of wakefulness between nocturnal and diurnal species, we assessed Fos expression patterns in the tuberomammillary (TMM), supramammillary (SUM), and raphe nuclei of male grass rats maintained in a 12:12 h light-dark cycle. Day-night profiles of Fos expression were observed in the ventral and dorsal TMM, in the SUM, …

Welcome To The Journal Of Evolution And Health, Aaron Blaisdell, Paul Jaminet, David C. Pendergrass

Aaron P Blaisdell

Welcome to the first issue of the Journal of Evolution and Health! The Journal of Evolution and Health is the peer-reviewed, open-access journal of the Ancestral Health Society, a community of scientists, healthcare professionals, and laypersons who collaborate to understand health challenges from an evolutionary perspective.

Understanding Less Than Nothing: Children's Neural Response To Negative Numbers Shifts Across Age And Accuracy, Margaret M. Gullick, George Wolford

Dartmouth Scholarship

We examined the brain activity underlying the development of our understanding of negative numbers, which are amounts lacking direct physical counterparts. Children performed a paired comparison task with positive and negative numbers during an fMRI session. As previously shown in adults, both pre-instruction fifth-graders and post-instruction seventh-graders demonstrated typical behavioral and neural distance effects to negative numbers, where response times and parietal and frontal activity increased as comparison distance decreased. We then determined the factors impacting the distance effect in each age group. Behaviorally, the fifth-grader distance effect for negatives was significantly predicted only by positive comparison accuracy, indicating that …

The Structure Of Consciousness, Lowell Keith Friesen

Open Access Dissertations

In this dissertation, I examine the nature and structure of consciousness. Conscious experience is often said to be phenomenally unified, and subjects of consciousness are often self-conscious. I ask whether these features necessarily accompany conscious experience. Is it necessarily the case, for instance, that all of a conscious subject's experiences at a time are phenomenally unified? And is it necessarily the case that subjects of consciousness are self-conscious whenever they are conscious? I argue that the answer to the former is affirmative and the latter negative.

In the first chapter, I set the stage by distinguishing phenomenal unity from other …

Brain Activity And Medical Diagnosis: An Eeg Study, Laila M. Ribas, Fábio T. Rocha, Neli R. Ortega, Armando F. Rocha, Eduardo Massad

Armando F Rocha

Despite new brain imaging techniques that have improved the study of the underlying processes of human decision-making, to the best of our knowledge, there have been very few studies that have attempted to investigate brain activity during medical diagnostic processing.The main purpose of this paper was to investigate brain electroencephalography (EEG) activity associated with diagnostic decision-making in the realm of veterinary medicine using X-rays as a fundamental auxiliary test. The principal component analysis revealed four patterns that accounted for 85% of the total variance in the EEG activity recorded while veterinary doctors read a clinical history, examined an X-ray image …

Unconscious Priming Requires Early Visual Cortex At Specific Temporal Phases Of Processing, Marjan Persuh, Tony Ro

Publications and Research

Although examples of unconscious shape priming have been well documented, whether such priming requires early visual cortex (V1/V2) has not been established. In the current study, we used TMS of V1/V2 at varying temporal intervals to suppress the visibility of preceding shape primes while the interval between primes and targets was kept constant. Our results show that, although conscious perception requires V1/V2, unconscious priming can occur without V1/V2 at an intermediate temporal interval but not at early (5–25 msec) or later (65–125 msec) stages of processing. Because the later time window of unconscious priming suppression has been proposed to interfere …

Sensory-Specific Appetition: Postingestive Detection Of Glucose Rapidly Promotes Continued Consumption Of A Recently Encountered Flavor, Kevin P. Myers, Marisa S. Taddeo, Emily K. Richards

Faculty Journal Articles

It is generally thought that macronutrients stimulate intake when sensed in the mouth (e.g., sweet taste) but as food enters the GI tract its effects become inhibitory, triggering satiation processes leading to meal termination. Here we report experiments extending recent work (see [1]) showing that under some circumstances nutrients sensed in the gut produce a positive feedback effect, immediately promoting continued intake. In one experiment, rats with intragastric (IG) catheters were accustomed to consuming novel flavors in saccharin daily while receiving water infused IG (5 ml/15 min). The very first time glucose (16% w/w) was infused IG instead of water, …

Self-Regulatory Depletion Increases Emotional Reactivity In The Amygdala, Dylan D. Wagner, Todd F. Heatherton

Dartmouth Scholarship

The ability to self-regulate can become impaired when people are required to engage in successive acts of effortful self-control, even when self-control occurs in different domains. Here, we used functional neuroimaging to test whether engaging in effortful inhibition in the cognitive domain would lead to putative dysfunction in the emotional domain. Forty-eight participants viewed images of emotional scenes during functional magnetic resonance imaging in two sessions that were separated by a challenging attention control task that required effortful inhibition (depletion group) or not (control group). Compared to the control group, depleted participants showed increased activity in the left amygdala to …

Effortless Awareness: Using Real Time Neurofeedback To Investigate Correlates Of Posterior Cingulate Cortex Activity In Meditators' Self-Report, Kathleen A. Garrison, Juan F. Santoyo, Jake H. Davis, Thomas A. Thomhill Iv, Catherine E. Kerr, Judson A. Brewer

Publications and Research

Neurophenomenological studies seek to utilize first-person self-report to elucidate cognitive processes related to physiological data. Grounded theory offers an approach to the qualitative analysis of self-report, whereby theoretical constructs are derived from empirical data. Here we used grounded theory methodology (GTM) to assess how the first-person experience of meditation relates to neural activity in a core region of the default mode network—the posterior cingulate cortex (PCC). We analyzed first-person data consisting of meditators' accounts of their subjective experience during runs of a real time fMRI neurofeedback study of meditation, and third-person data consisting of corresponding feedback graphs of PCC activity …

Exercise-Induced Hypoxia, Angiogenesis, And Behavioral Flexibility In The Adult Rat, Kiersten Lee Berggren

Theses and Dissertations

Exercise induces a myriad of effects on the brain from the growth of new capillaries and neurons, to improvements in cognitive performance. Additionally, recent research has shown that commencement of an exercise regimen also causes apoptosis. Therefore, it is possible that exercise-induced increases in oxygen demand cause the brain to transiently experience a state of hypoxia. To investigate this hypothesis, we measured protein levels of hypoxia inducible factor 1 alpha (HIF-1α), a transcription factor known to be upregulated in conditions of hypoxia or ischemia, in animals exposed to a single bout of treadmill exercise. After exercise animals were sacrificed at …

The Role Of A Camkii/Pka-Protein Degradation-Glur2 Pathway In The Control Of Memory Updating Following Retrieval, Timothy Jarome

Theses and Dissertations

Reconsolidation is thought to be a process whereby consolidated memories can be modified following retrieval. However, very little is known about the molecular mechanisms that regulate this reconsolidation process. In the present series of experiments we tested if memories "destabilize" or become labile following retrieval through a specific signaling pathway. We found that retrieval of a contextual fear memory differentially increased proteasome activity in the amygdala and hippocampus and resulted in unique changes in AMPA receptor subunit expression in these brain regions. These changes were dependent on CaMKII activity, which was required for increases in Rpt6-S120 phosphorylation, proteasome activity and …

Dissociation Of Β1 And Β2 Adrenergic Receptor Subtypes In Retrieval And Reconsolidation Of A Cocaine Conditioned Place Preference, Michael Fitzgerald

Theses and Dissertations

Drug-seeking behavior is maintained by encounters with drug-associated cues, and disrupting retrieval or reconsolidation of the drug-cue associations could reduce the risk of relapse. Previous work has shown beta-adrenergic receptor (beta-AR) antagonists can prevent retrieval or reconsolidation of a cocaine conditioned place preference (CPP) when administered either before or after test, respectively (Otis and Mueller, 2011; Otis et al., 2013). However, the specific beta-AR subtypes that mediate retrieval and reconsolidation of a cocaine CPP remain unknown. Here we used selective blockade of & beta-1 or beta-2-AR subtypes to determine the effects on retrieval and reconsolidation of a cocaine CPP. During …

Alternations Of Nmda And Gabab Receptor Function In Development: A Potential Animal Model Of Schizophrenia, Monica Bolton

UNLV Theses, Dissertations, Professional Papers, and Capstones

Schizophrenia is a debilitating mental disorder that affects up to 3% of the world population. The behavioral symptoms are categorized into positive and negative symptoms, which appear during late adolescence/early adulthood. Unfortunately, the underlying cellular and molecular mechanisms of the disease are poorly understood. Several hypotheses exist to explain mechanisms contributing to these behavioral alterations. One model proposes that a reduced function of the NMDA glutamate receptor on specific GABAergic interneurons may be responsible for deficits in schizophrenia. Post-mortem investigations provide evidence of reductions in both glutamate and GABA-related proteins in patients with schizophrenia. Further, GABAergic interneurons that are activated …

The Influence Of Proficiency And Age Of Acquisition On Second Language Processing: An Fmri Study Of Mandarin-English Bilinguals, Emily S. Nichols

Electronic Thesis and Dissertation Repository

Research investigating the neural correlates of second language (L2) processing has usually studied age of acquisition (AoA) and proficiency separately. Presently, we examined both in parallel, treated as continuous variables. We used fMRI to study neural activity for L2 processing in adult native Mandarin speakers who are L2 English speakers. Behavioral measures of language proficiency and AoA were obtained from subjects prior to performing a picture-word matching task during an fMRI scan. Brain activity during L2 English processing was shown to be independently affected by AoA and proficiency; activity in left superior temporal gyrus and right parahippocampal gyrus was modulated …

Lesions Of The Intergeniculate Leaflet Lead To A Reorganization In Circadian Regulation And A Reversal In Masking Responses To Photic Stimuli In The Nile Grass Rat, Andrew J. Gall, Laura Smale, Lily Yan, Antonio A. Nunez

Faculty Publications

Light influences the daily patterning of behavior by entraining circadian rhythms and through its acute effects on activity levels (masking). Mechanisms of entrainment are quite similar across species, but masking can be very different. Specifically, in diurnal species, light generally increases locomotor activity (positive masking), and in nocturnal ones, it generally suppresses it (negative masking). The intergeniculate leaflet (IGL), a subdivision of the lateral geniculate complex, receives direct retinal input and is reciprocally connected with the primary circadian clock, the suprachiasmatic nucleus (SCN). Here, we evaluated the influence of the IGL on masking and the circadian system in a diurnal …

Targeted Training Of The Decision Rule Benefits Rule-Guided Behavior In Parkinson’S Disease, Shawn W. Ell

Psychology Faculty Scholarship

The impact of Parkinson’s disease (PD) on rule-guided behavior has received considerable attention in cognitive neuroscience. The majority of research has used PD as a model of dysfunction in fronto-striatal networks, but very few attempts have been made to investigate the possibility of adapting common experimental techniques in an effort to identify the conditions that are most likely to facilitate successful performance. The present study investigated a targeted training paradigm designed to facilitate rule learning and application using rule-based categorization as a model task. Participants received targeted training in which there was no selective-attention demand (i.e., stimuli varied along a …

Immediate Early Gene Expression In Medial Prefrontal Cortex And Hippocampus As A Function Of Aging, Megha Sehgal

Theses and Dissertations

Normal aging is accompanied by cognitive decline that differs from other aging-related pathological states like Alzheimer's disease. With an increasing proportion of the world population falling in an age group of 65 years and above, a preventive gerontological approach would improve the quality of life in the elderly. Especially important in this regard is the early detection of cognitive decline, so that appropriate measures can be taken to prevent development of cognitive deficits. Impairment in cognitive flexibility, the ability to modify a previously learnt behavior, is one such measure of impairment across species in aged animals. Previous work from our …

The Role Of Nmda Receptors In Extinction Of Cocaine Self-Administration, Madalyn Hafenbreidel

Theses and Dissertations

Relapse is highly prevalent among recovering addicts, and can be triggered by associations made between the rewarding effects of the drug and cues, such as drug paraphernalia or contexts. Inhibiting these associations, through new extinction learning, could help reduce relapse rates. Extinction is formed in phases, like other types of memory. The memory first is acquired in short-term memory, then is consolidated into long-term storage from which it can be retrieved at a later time (Quirk & Mueller, 2008). NMDA receptors are necessary for extinction in other paradigms (Santini, Muller, & Quirk, 2001), and we previously found that blocking NMDA …

The Effects Of Pedagogical Conditions On Second Language Acquisition, Mccall Evonne Sarrett

Chancellor’s Honors Program Projects

No abstract provided.