Neuroscience and Neurobiology Commons^™

Clamping Of Intracellular Ph In Neurons From Neonatal Rat Brainstem During Hypercapnia, Vivian C. Nanagas

Browse all Theses and Dissertations

In this work, I have made attempts to clamp intracellular pH in the presence of hypercapnic acidosis (HA) in neurons from the locus coeruleus (LC) and nucleus of the solitary tract (NTS) in neonatal rat (ages P3 to P17) brainstem slices. Two approaches were used to minimize hypercapnia-induced ΔpH_i: 1) an increase in intracellular buffering power with a high HEPES concentration using whole cell patching techniques in individual neurons, and 2) a weak acid diffusion technique that relies on an efflux of weak acid to counterbalance HA influx thereby clamping pH_i in multiple neurons at once. pH …

Conceptual Circuit Models Of Neurons, Bo Deng

Department of Mathematics: Faculty Publications

A systematic circuit approach tomodel neurons with ion pump is presented here by which the voltage-gated current channels are modeled as conductors, the diffusion-induced current channels are modeled as negative resistors, and the one-way ion pumps are modeled as one-way inductors. The newly synthesized models are different from the type of models based on Hodgkin-Huxley (HH) approach which aggregates the electro, the diffusive, and the pump channels of each ion into one conductance channel. We show that our new models not only recover many known properties of the HH type models but also exhibit some new that cannot be extracted …

Brain Activation During Anticipation Of Sound Sequences, Amber M. Leaver, Jennifer Van Lare, Brandon Zielinski, Andrea R. Halpern, Josef P. Rauschecker

Faculty Journal Articles

Music consists of sound sequences that require integration over time. As we become familiar with music, associations between notes, melodies, and entire symphonic movements become stronger and more complex. These associations can become so tight that, for example, hearing the end of one album track can elicit a robust image of the upcoming track while anticipating it in total silence. Here, we study this predictive “anticipatory imagery” at various stages throughout learning and investigate activity changes in corresponding neural structures using functional magnetic resonance imaging. Anticipatory imagery (in silence) for highly familiar naturalistic music was accompanied by pronounced activity in …

A Rat Model Examining Behavioral And Neurochemical Effects Of Passive Exposure To Aggression On Observers, Hideo Suzuki

Dissertations

Previous studies have consistently reported that passive exposure to aggression is a risk of aggressive inclinations for a human witness. However, it is unclear whether a witness' aggressiveness is semi-permanently socialized or temporarily primed. Furthermore, a neurochemical mechanism of passive exposure to aggression also remains unaddressed in clinical literature. The present research used a rat model to clarify the behavioral and neurochemical effects of passive exposure to aggression. First, rats were screened for their aggressiveness after they were acutely or chronically exposed to aggression or non-aggression. It was found that observer rats chronically exposed to aggression exhibited more aggression than …

A Neuroeconomic Theory Of The Decision Process, John Dickhaut, Aldo Rustichini, Vernon L. Smith

ESI Publications

We develop a neuronal theory of the choice process (NTCP), which takes a subject from the moment in which two options are presented to the selection of one of the two. The theory is based on an optimal signal detection, which generalizes the signal detection theory by adding the choice of effort as optimal choice for a given informational value of the signal for every effort level and a cost of effort. NTCP predicts the choice made as a stochastic choice: That is, as a probability distribution over two options in a set, the level of effort provided, the error …

Does Type Of Stimulus Influence Task-Irrelevant Evaluative Categorization Processes?, Guadalupe Corral

Open Access Theses & Dissertations

The effect of stimulus type on task-irrelevant evaluative categorization was examined in two separate studies by using the P3 component from event-related brain potentials. The first study presented idiosyncratic stimuli consisting of individuals that were rated by participants as either positive or negative within sequences of pictorial and verbal stimuli. The second study presented sequences of novel and familiar stimuli consisting of previously normed unattractive and neutral individuals. It was hypothesized that pictures would elicit task-irrelevant evaluative categorization processes and so would novel stimuli (relative to words and familiar stimuli, respectively). Task-irrelevance was examined by assessing P3 peak amplitude to …

Characterization Of The Behavioral And Neurochemical Effects Of Nicotine Withdrawal In Adolescent And Adult Rats., Luis Alberto Natividad

Open Access Theses & Dissertations

Previous studies have demonstrated that the behavioral effects of nicotine withdrawal are lower in adolescent versus adult rats. However, the neurochemical mechanisms that mediate these developmental differences are presently unclear. Much work has shown that nicotine reward is mediated via enhanced dopamine neurotransmission in the mesolimbic pathway which originates in the ventral tegmental area (VTA) and terminates in several forebrain structures including the nucleus accumbens (NAcc). More recently, studies have shown that nicotine withdrawal produces a decrease in NAcc dopamine transmission, an effect that is believed to serve as a neurochemical marker of withdrawal in adult rodents. The goal of …

Elucidating The Role Of The Α7 Nicotinic Receptor In The Etiology Of Schizophrenia., Michelle Johnson Chandley

Electronic Theses and Dissertations

The α7 subunit of the nicotinic receptor, a ligand gated ion channel with an affinity for nicotine, has long been implicated in the pathophysiology of schizophrenia due to the extremely high rate of smoking within the patient population. However, the exact role of the receptor has never fully been determined. In the following studies, various functions the receptor may assume in disease state are evaluated. There is a strong relationship between the immune system and schizophrenia, with the α7 subunit possibly serving as the link between the two. One of the following studies looks at the possibility of the receptor …

Neural Substrates Of Sound–Touch Synesthesia After A Thalamic Lesion, Michael S. Beauchamp, Tony Ro

Publications and Research

Neural plasticity induced by stroke can mediate positive outcomes, such as recovery of function, but can also result in the formation of abnormal connections with negative consequences for perception and cognition. In three experiments using blood-oxygen level dependent (BOLD) functional magnetic resonance imaging, we examined the neural substrates of acquired auditory-tactile synesthesia, in which certain sounds can produce an intense somatosensory tingling sensation in a patient with a thalamic lesion. Compared with nine normal controls, the first experiment showed that the patient had a threefold greater BOLD response to sounds in the parietal operculum, the location of secondary somatosensory cortex. …

Clustering Neural Spike Trains With Transient Responses, John D. Hunter, Jianhong Wu, John Milton

WM Keck Science Faculty Papers

The detection of transient responses, i.e. nonstationarities, that arise in a varying and small fraction of the total number of neural spike trains recorded from chronically implanted multielectrode grids becomes increasingly difficult as the number of electrodes grows. This paper presents a novel application of an unsupervised neural network for clustering neural spike trains with transient responses. This network is constructed by incorporating projective clustering into an adaptive resonance type neural network (ART) architecture resulting in a PART neural network. Since comparisons are made between inputs and learned patterns using only a subset of the total number of available dimensions, …

The Effects Of A 40mg Lasik Treatment On The Threshold Frequency Of Electrically Induced Muscle Cramps, Sara F. Bergeron

All-Inclusive List of Electronic Theses and Dissertations

Context: Muscle cramps that are caused by exercise can be painful and debilitating to an active individual. One theory to explain the cause of exerciseassociated muscle cramps is dehydration. While dehydration is a popular theory it has 111 yet to be studied as a sole factor to the incidence of muscle cramps. Objective: To examine the effect of mild dehydration on the threshold frequency (TF) of electrically induced muscle cramps (EIMC) in the flexor hallucis brevis.

Medial Temporal Lobe Bold Activity At Rest Predicts Individual Differences In Memory Ability In Hhealthy Young Adults, Gagan S. Wig, Scott T. Grafton, Kathryn E. Demos, George L. Wolford, Steven E. Petersen, William M. Kelley

Dartmouth Scholarship

Human beings differ in their ability to form and retrieve lasting long-term memories. To explore the source of these individual differences, we used functional magnetic resonance imaging to measure blood-oxygen-level-dependent (BOLD) activity in healthy young adults (n = 50) during periods of resting fixation that were interleaved with periods of simple cognitive tasks. We report that medial temporal lobe BOLD activity during periods of rest predicts individual differences in memory ability. Specifically, individuals who exhibited greater magnitudes of task-induced deactivations in medial temporal lobe BOLD signal (as compared to periods of rest) demonstrated superior memory during offline testing. This relationship …

Maternal Photoperiodic History Affects Offspring Development In Syrian Hamsters, Annaliese K. Beery, Matthew J. Paul, Irving Zucker

Neuroscience: Faculty Publications

During the first 7 weeks of postnatal life, short day lengths inhibit the onset of puberty in many photoperiodic rodents, but not in Syrian hamsters. In this species, timing of puberty and fecundity are independent of the early postnatal photoperiod. Gestational day length affects postnatal reproductive development in several rodents; its role in Syrian hamsters has not been assessed. We tested the hypothesis that cumulative effects of pre- and postnatal short day lengths would restrain gonadal development in male Syrian hamsters. Males with prenatal short day exposure were generated by dams transferred to short day lengths 6 weeks, 3 weeks, …

Examining Neurophysiological Evidence Of Age-Related Interactions Of Sensory And Cognitive Processes During Speech Processing, Cady Kristen Block

Psychology Theses & Dissertations

The present study sought to examine the contribution of sensory and cognitive factors on speech processing as evidenced by ERP measures and to find support for the Sensory Cognitive Interaction Theory (SCIT) and the Effortfulness Hypothesis in that older adults. who experience sensory deficits with normal aging. must put forth increased effort during early sensory stages of speech processing that may compromise subsequent semantic performance and recall of information. In the present investigation. younger and older adults performed a sentence verification task at low and high presentation levels (PL). Accuracy and response time to sentence verifications were assessed along with …

Effects Of Pre-Pubertal Social Experiences On The Responsiveness Of Juvenile Rats To Predator Odors, Stephen M. Siviy

Psychology Faculty Publications

The extent to which social variables may modulate the fear associated with a predator cue was assessed in juvenile rats. Cat odor reduced play to a comparable extent in both socially housed and isolate-housed rats, although socially housed rats exhibited more risk assessment during extinction. Rats that had played previously in the context used for assessing fear hid slightly less when exposed to cat odor than those rats that had not played previously in the testing context. However, no other differences were found between these two groups suggesting that prior social experience with the testing context has minimal effects on …

Anti-Inflammatory Effects Of Ppar-Gamma In Surgical Brain Injury (Sbi), Amy Hyong

Loma Linda University Electronic Theses, Dissertations & Projects

Introduction: Brain injury can be caused by neurosurgical procedures themselves, due to direct trauma, retractor stretch, intraoperative hemorrhage and electrocautery damage. As a result of this surgical brain injury (SBI) postoperative complications such as inflammation, brain edema, and cell death can occur in the susceptible brain areas. Cerebral inflammation is a known contributor to the pathophysiology of brain injury. Following brain injury, the release of inflammatory mediators facilitates the development of BBB breakdown, cerebral edema, oxidative stress and neuronal death, resulting in further tissue damage in the brain and poor neurological outcomes. This study evaluates whether the use of a …

Impact Of Apoe Deficiency During Synaptic Remodeling In The Mouse Olfactory Bulb, Ikemefuna Nwosu, Salina Gairhe, Robert G. Struble, Britto P. Nathan

Faculty Research & Creative Activity

In this study we examined the role of apoE on the rate of synaptic recovery in the olfactory bulb (OB) following olfactory epithelium (OE) lesioning in mice. We used both immunoblotting and immunohistochemical techniques to compare the density of OB synaptophysin (Syn, a synaptic marker) in apoE-gene deficient/knockout (KO) mice and wild-type (WT) mice following OE lesion. We found that the whole bulb concentrations of Syn, measured by immunoblotting, declined sharply following injury in both WT and KO mice during the degenerative phase (3–7 days). After this initial decline, the Syn concentration gradually increased to normal levels by 56 days …

Impact Of Apoe Deficiency During Synaptic Remodeling In The Mouse Olfactory Bulb, Ikemefuna Nwosu, Salina Gairhe, Robert Struble, Britto Nathan

Faculty Research & Creative Activity

In this study we examined the role of apoE on the rate of synaptic recovery in the olfactory bulb (OB) following olfactory epithelium (OE) lesioning in mice. We used both immunoblotting and immunohistochemical techniques to compare the density of OB synaptophysin (Syn, a synaptic marker) in apoE-gene deficient/knockout (KO) mice and wild-type (WT) mice following OE lesion. We found that the whole bulb concentrations of Syn, measured by immunoblotting, declined sharply following injury in both WT and KO mice during the degenerative phase (3–7 days). After this initial decline, the Syn concentration gradually increased to normal levels by 56 days …

Amphetamine Sensitization And In Vivo Microdialysis Of The Nucleus Accumbens Core Of Adult Male And Female Rats D2-Primed As Neonates., Zackary Adam Cope

Electronic Theses and Dissertations

Neonatal administration of quinpirole produces significant increases in D₂ receptor sensitivity that persists into adulthood. This phenomenon, known as D₂ receptor priming, is consistent with pathology in schizophrenia. Rats were administered quinpirole or saline postnatally and raised to adulthood. In adulthood, rats were administered d-amphetamine sulfate or saline every other day and were placed in a locomotor arena where activity was measured over 7 trials. Results showed that D₂-primed rats receiving amphetamine were higher in locomotor activity across all days of testing compared to other groups. This effect was more prominent in males than in females. …

Blunted Cystine–Glutamate Antiporter Function In The Nucleus Accumbens Promotes Cocaine-Induced Drug Seeking, Kristen S. Kau, Aric Madayag, John R. Mantsch, Mark D. Grier, Omer Abdulhameed, David A. Baker

Biomedical Sciences Faculty Research and Publications

Repeated cocaine alters glutamate neurotransmission, in part, by reducing cystine–glutamate exchange via system x_c−, which maintains glutamate levels and receptor stimulation in the extrasynaptic compartment. In the present study, we undertook two approaches to determine the significance of plasticity involving system x_c−. First, we examined whether the cysteine prodrug N-acetylcysteine attenuates cocaine-primed reinstatement by targeting system x_c−. Rats were trained to self-administer cocaine (1 mg/kg/200 μl, i.v.) under extended access conditions (6 h/day). After extinction training, cocaine (10 mg/kg, i.p.) primed reinstatement was assessed in rats pretreated with N-acetylcysteine (0–60 mg/kg, i.p.) in the …

Criterion Validity Of The Wechsler Intelligence Scale For Children - Fourth Edition After Pediatric Traumatic Brain Injury, Jacobus Donders, Kelly Janke

University Faculty Publications and Creative Works

The performance of 40 children with complicated mild to severe traumatic brain injury on the Wechsler Intelligence Scale for Children - Fourth Edition (WISC-IV; Wechsler, 2003) was compared with that of 40 demographically matched healthy controls. Of the four WISC-IV factor index scores, only Processing Speed yielded a statistically significant group difference (p < .001) as well as a statistically significant negative correlation with length of coma (p < .01). Logistic regression, using Processing Speed to classify individual children, yielded a sensitivity of 72.50% and a specificity of 62.50%, with false positive and false negative rates both exceeding 30%. We conclude that Processing Speed has acceptable criterion validity in the evaluation of children with complicated mild to severe traumatic brain injury but that the WISC-IV should be supplemented with other measures to assure sufficient accuracy in the diagnostic process.

The Development Of Day-Night Differences In Sleep And Wakefulness In Norway Rats And The Effect Of Bilateral Enucleation, Andrew J. Gall, William D. Todd, Baisali Ray, Cassandra M. Coleman, Mark S. Blumberg

Faculty Publications

The suprachiasmatic nucleus (SCN) exhibits circadian rhythmicity in fetal and infant rats, but little is known about the consequences of this rhythmicity for infant behavior. Here, in Experiment 1, we measured sleep and wakefulness in rats during the day and night in postnatal day (P)2, P8, P15 and P21 subjects. As early as P2, day-night differences in sleep-wake activity were detected. Nocturnal wakefulness began to emerge around P15 and was reliably expressed by P21. We hypothesized that the process of photic entrainment over the first postnatal week, which depends upon the development of connectivity between the retinohypothalamic tract (RHT) and …

Day Length And Estradiol Affect Same-Sex Affiliative Behavior In The Female Meadow Vole, Annaliese K. Beery, Theresa J. Loo, Irving Zucker

Neuroscience: Faculty Publications

Non-sexual social bonding between adult mammals remains poorly understood, despite its importance in many species. Female meadow voles are territorial and nest alone in long summer day lengths when circulating estradiol concentrations are high, but cohabit in groups in short winter photoperiods when estradiol secretion is low. The influence of day length and estradiol on same-sex huddling behavior was assessed in adult female pairs housed together in long day lengths (LDs) or short day lengths (SDs) from weaning. The behavior of intact, ovariectomized, and estradiol-treated ovariectomized females from each photoperiod was assessed during 3 hour partner preference tests. Intact SD …

Factors That Affect Performance On Executive Functioning After Coronary Artery Bypass Grafting, Sapna Mahesh Patel

Loma Linda University Electronic Theses, Dissertations & Projects

Research suggests that individuals who undergo coronary artery bypass grafting (CABG) experience declines in neuropsychological functioning post-operatively. This decline has been observed in up to 80% of patients early after surgery, and in up to 30% of patients after six months. Many studies have examined the potential effects of CABG on neuropsychological functioning in general, and numerous studies have found that executive functions are impaired in particular. However, none have examined what factors contribute to observed executive dysfunction after CABG. This study investigated the role of memory functions on executive functions in a selected sample of patients undergoing CABG. This …

The Parallel Worm Tracker: A Platform For Measuring Average Speed And Drug-Induced Paralysis In Nematodes, Daniel Ramot, Brandon E. Johnson, Tommie L. Berry Jr., Lucinda Carnell, Miriam B. Goodman

All Faculty Scholarship for the College of the Sciences

Background

Caenorhabditis elegans locomotion is a simple behavior that has been widely used to dissect genetic components of behavior, synaptic transmission, and muscle function. Many of the paradigms that have been created to study C. elegans locomotion rely on qualitative experimenter observation. Here we report the implementation of an automated tracking system developed to quantify the locomotion of multiple individual worms in parallel.

Methodology/Principal Findings

Our tracking system generates a consistent measurement of locomotion that allows direct comparison of results across experiments and experimenters and provides a standard method to share data between laboratories. The tracker utilizes a video camera …

Colocalization And Distribution Of Hcn4 Channels And A Maguk Protein In Mammalian Sinoatrial Myocytes, Padmastuti Akella

Honors Scholar Theses

The sinoatrial node is known as the pacemaker of the heart. It controls the rate at which action potentials are generated and propagate through the sinoatrial myocytes. This thesis is an attempt to identify the colocalization of a specific ion channel (HCN4 channel) with a class of scaffolding protein (MAGUK proteins) within the sinoatrial myocyte. The colocalization of these two variables was performed using immunocytochemistry on murine sinoatrial myocytes and experimental results revealed the existence of a strong colocalization between the two variables. Images collected from the confocal microscope and analyzed using ImageJ software revealed a strong dependent correlation between …

Expression Of Nicotinic Acetylcholine Receptor Mrna As A Function Of Age In Whole Hippocampus Preparations From Wistar Rats, Kasey C. Welch

Theses and Dissertations

Whole hippocampus preparations, isolated bilaterally, from untreated Wistar rats at various ages (10-90 days old) were analyzed for the mRNA expression of the alpha 2, alpha 3, alpha 4, alpha 5, alpha 7, beta 2, beta 3, and beta 4 neuronal nicotinic acetylcholine receptor subunits. To do so, RNA was isolated from acutely isolated hippocampal samples, converted to cDNA by means of a reverse transcription reaction, then analyzed with quantitative real-time PCR to determine the relative levels of the mRNAs the cells were expressing at the age when the samples were obtained. The relative expression of the levels of RNA …

Maternal Cocaine Administration In Mice Alters Dna Methylation And Gene Expression In Hippocampal Neurons Of Neonatal And Prepubertal Offspring, Svetlana I. Novikova, Fang He, Jie Bai, Nicholas J. Cutrufello, Michael S. Lidow, Ashiwel S. Undieh

Publications and Research

Previous studies documented significant behavioral changes in the offspring of cocaine-exposed mothers. We now explore the hypothesis that maternal cocaine exposure could alter the fetal epigenetic machinery sufficiently to cause lasting neurochemical and functional changes in the offspring. Pregnant CD1 mice were administered either saline or 20 mg/kg cocaine twice daily on gestational days 8–19. Male pups from each of ten litters of the cocaine and control groups were analyzed at 3 (P3) or 30 (P30) days postnatum. Global DNA methylation, methylated DNA immunoprecipitation followed by CGI2 microarray profiling and bisulfite sequencing, as well as quantitative real-time RT-PCR gene expression …

Using A Paradigm Shift To Teach Neurobiology And The Nature Of Science—A C.R.E.A.T.E.-Based Approach, Sally G. Hoskins

Publications and Research

Decades ago, classic experiments established the phenomenon of “neural induction” (Spemann and Mangold, 1924; Holtfreter, 1933). It appeared clear that amphibian ectoderm was pre-programmed to form epidermis, and that the neural phenotype was induced by a chemical signal from mesoderm. The “ectoderm makes skin, unless induced to make nervous system” model appeared in many textbooks. This interpretation, however, was not simply incorrect but 180 degrees out of alignment with the actual situation. As subsequently demonstrated, the default state of amphibian ectoderm is neuronal, and the expression of the epidermal phenotype requires cell signaling (Hemmati-Brivanlou and Melton, 1992; 1994; 1997). In …

Treg Depletion Inhibits Efficacy Of Cancer Immunotherapy: Implications For Clinical Trials., James Curtin, Marianela Candolfi, Tamer Fakhouri, Chunyan Liu, Anderson Alden, Matthew Edwards, Pedro Lowenstein, Maria Castro

Articles

BACKGROUND: Regulatory T lymphocytes (Treg) infiltrate human glioblastoma (GBM); are involved in tumor progression and correlate with tumor grade. Transient elimination of Tregs using CD25 depleting antibodies (PC61) has been found to mediate GBM regression in preclinical models of brain tumors. Clinical trials that combine Treg depletion with tumor vaccination are underway to determine whether transient Treg depletion can enhance anti-tumor immune responses and improve long term survival in cancer patients. FINDINGS: Using a syngeneic intracrabial glioblastoma (GBM) mouse model we show that systemic depletion of Tregs 15 days after tumor implantation using PC61 resulted in a decrease in Tregs …