Neuroscience and Neurobiology Commons^™

Astroglial Boundary Formation And Epha4 Signaling In Neuroblast Migration, Nicholas B. Gallo

Honors Scholar Theses

Adult neurogenesis, the process of generating new neurons from neural precursors, is a highly complex process that is limited to two specific areas of the brain, the dentate gyrus of the hippocampus and the subventricular zone (SVZ). Despite continued research investigating neurogenesis in these two regions, we still lack a fundamental understanding of the molecular mechanisms of neural cell division, migration, differentiation, and integration in the postnatal brain. In particular, the rostral migratory stream (RMS), which is a cellular migratory route for newly generated neuronal precursors that travel from the SVZ to the olfactory bulb, will provide a useful model …

The New Normal: Goodness Judgments Of Non-Invariant Speech, Julia R. Drouin

Honors Scholar Theses

Previous research has found that perceptual learning, or normalizing the idiosyncratic phonemes of speech, causes a shift in speech sound category boundaries. The present study examined if perceptual learning was limited to the boundary or if also caused a shift in internal category structure. Seventeen individuals participated in three behavioral tasks to explicate this question. In the Lexical Decision task, participants were trained in either /s/-biasing or /ʃ/- biasing context. In the Goodness Judgment task, participants rated a continuum of sounds on perceived /s/ goodness using a designated scale. Finally, in the Phoneme Identification task, participants listened to the same …

Characterization Of The Ependymal Barrier Due To Human Aging And Injury In Murine Models, Ye Sun

University Scholar Projects

Ventriclulomegaly, or the expansion of the ventricles in the brain, is a phenomenon associated with age and injury to the brain. The ependymal layer that encases the ventricles displays certain degrees of plasticity and regenerative ability due to its associated stem cell niche, the subventricular zone (SVZ). Previous research in the Conover Lab has shown that in the mouse, which maintains an actively proliferating SVZ into adulthood, there is an intact ependymal monolayer throughout normal aging, with maintained lateral ventricle size with some degree of stretching. In contrast, the human SVZ declines in proliferative capacity after infancy, and age-related changes …

The Effect Of Repeated Mild Traumatic Brain Injury On Ventricular Volume And Microglial Activation, Lillian Rose Talbot

Honors Scholar Theses

As the leading cause of death and disability in individuals under the age of 45-years-old, Traumatic Brain Injury (TBI) is a public health crisis that demands the attention of the scientific and medical community [28]. The majority of all TBIs that occur in the United States each year are a non-deadly yet detrimental form of closed brain injury known as mild TBI (mTBI) or concussion [6]. Athletes, young people and military personnel all face a high risk of acquiring mTBI as a result of their environments. In our study we have chosen to model repeated mTBI (rmTBI) in the mouse …

The Effects Of Aging And Injury On The Murine Ependymal Barrier And Subventricular Zone, John J. Peters

Honors Scholar Theses

Previous research has shown that numerous age-related changes occur in the subventricular zone (SVZ) and diminish the neurogenic output of the region. Here, various age-related changes in the structure of the lateral ventricle, the ependymal barrier, and the SVZ were examined. It was found that the walls of the lateral ventricles move together, adhere, and eventually fuse. This results in a degradation of the SVZ. Other changes associated with aging were found, including ependymal cell stretching, heightened, ependymal repair, changes in CSF flow velocity and dynamics, and altered ependymal cell polarity. These changes may be related to the process of …

Direct Reprogramming Of Mouse Embryonic Fibroblasts Into Gabaergic Neurons, Nicholas J. Wasko

Honors Scholar Theses

Recent studies in which mouse and human fibroblasts were directly reprogrammed into functional neurons have demonstrated that lineage-specific transcription factors can override differentiation processes previously thought to be irreversible. Notably, three factors have been shown to be required for the induction of neural cell fate. Subsequent experiments have identified additional factors capable of generating specific neuronal subtypes, including motor neurons and dopaminergic neurons, but the factors necessary for inducing GABAergic neuronal fate have yet to be elucidated. Here, factors linked to GABAergic fate were transfected into mouse fibroblasts in order to identify candidate factors for inhibitory interneuron direct reprogramming. Results …

Modulation Of Synaptic Transmission By Adenosine In Layer 2/3 Of The Rat Visual Cortex In Vitro, Nicholas M. Bannon

Master's Theses

No abstract provided.

Copper Signaling In The Mammalian Nervous System: Synaptic Effects, Eric D. Gaier, Betty A. Eipper, Richard E. Mains

UCHC Articles - Research

Copper (Cu) is an essential metal present at high levels in the CNS. Its role as a co-factor in mitochondrial ATP production and in other essential cuproenzymes is well defined. Menkes and Wilson’s diseases are severe neurodegenerative conditions that demonstrate the importance of Cu transport into the secretory pathway. Brain levels of Cu, which is almost entirely protein bound, exceed extracellular levels by more than a hundred-fold. Cu stored in the secretory pathway is released in a Ca²⁺-dependent manner and can transiently reach concentrations over 100 µM at synapses. The ability of low µM levels of Cu to …

Effects Of Neonatal Hypoxic Ischemic Brain Injury On Spatial Working Memory, Amanda L. Smith

Master's Theses

Children born prematurely or at very low birth weight (VLBW) have an increased risk for hypoxic ischemic brain injury (HI). HI refers to a lack of adequate blood and oxygen flow in the brain. HI can also occur in the term infant due to birth complications such as prolonged labor, placental dysfunction, or cord prolapse. In both populations (though exact patterns of neuropathology vary) brain damage is likely to occur in the form of decreased hippocampal and cortical volume, and enlargement of the ventricles (Kesler et al., 2004, Nagy et al., 2009). Resulting neuropathology can in turn lead to cognitive …

Diffusion Barriers Of The Lateral Ventricular System, Anitha Saravanakumar

Master's Theses

Adult neurogenesis in mammalian brain has become a well-accepted phenomenon. The neural stem cells in the sub ventricular zone (SVZ) along the lateral wall of the lateral ventricle, the largest germinal center of adult neurogenesis, are maintained by the neural stem cell niche. One prominent feature of the niche is its close proximity to the cerebral spinal fluid (CSF). The role of micromolecules (such as ions, water and gases) present in the CSF and diffusing through the lateral ventricular wall and how the stem cell micro-environment is maintained is poorly understood. The cytoarchitecture of the lateral ventricular wall with a …

The Effects Of Rectal Temperature And Hydration Status On Perceptual Ratings In Dehydrating Males, Ethan A. Talbot

Honors Scholar Theses

Athletes push the limits of what the human body can handle every day. When they exercise in the heat, they can attain dangerous levels of internal temperature and dehydration. Since athletes are sometimes not aware when they are experiencing severe hyperthermia or hypohydration, it is of interest to anyone who exercises in the heat to study whether athletes are consciously aware that they are approaching dangerous physiological limits. This study compares the perceptual values of athletes exercising in the heat to the changes in their internal temperature and hydration status, to see if athletes can reliably predict their heat and …

Evidence For Pit-Type (Slc20) And Napi-Ii-Type (Slc34) Transporters In The Rat Choroid Plexus, Hien M. Le

Honors Scholar Theses

: A major function of the brain choroid plexus (CP) is to regulate the exchange of solutes between the blood plasma and the cerebrospinal fluid (CSF) using selective transporters. CSF inorganic phosphate (P_i) concentration is maintained at about one-half that of plasma and is potentially important because of its regulatory, structural, and biochemical functions. Phosphate is critical for ATP and DNA formation, the linked regulation between phosphate and calcium, and as an intracellular buffer. The human body has two major P_i transporter gene families known as SLC34 (NaPi-II) and SLC20 (PiT), which have wide tissue distribution. Although …

Detection Of Sk2 Channels On Hippocampal Neurons, Jamie L. Maciaszek

Master's Theses

Calcium-activated small conductance potassium channels (SK) are crucial for synaptic plasticity, sleep, and learning and memory (Hammond, Bond et al. 2006; Cueni, Canepari et al. 2008; Lin, Lujan et al. 2008). Despite the recent progress on SK channel physiology, the precise spatial organization of SK channels in neurons has remained unknown. Such knowledge is critical as the subcellular distribution of SK channels is an important determinant of neuronal excitability. Currently, there are no techniques to image ion channel distribution quantitatively at the nanometer scale in living cells. Here, it is demonstrated that integration of natural toxins with single molecule atomic …

Septotemporal Variation In Theta Rhythm Dynamics: Effects Of Speed And Habituation, James Hinman

Master's Theses

Theta (6-12 Hz) field potentials and the synchronization (coherence) of these potentials present neural network indices of hippocampal physiology. Theta signals within the hippocampal formation may reflect alterations in sensorimotor integration, the flow of sensory input and/or distinct cognitive operations. While the power and coherence of theta signals vary across lamina within the septal hippocampus, limited information is available about variation in these indices across the septotemporal (long) or areal axis. The present study examined the relationship of locomotor speed to theta indices at CA1 and DG sites across the septotemporal axis as well as in the entorhinal cortex. Our …

Investigation Of Mirnas Expression In A Citron-Kinase Mutant Model Of Microcephaly, Shan Parikh

Master's Theses

Mutation of Citron-Kinase (Cit-K) in rodents causes substantial reductions in the number of neurons generated in the CNS and results in a primary microcephaly-like phenotype. Evidence from drosophila genetics has further established a genetic link between Cit-K and a protein Argonaut 1 (AGO1), which is required for proper functioning of the miRNA machinery (2). Experiments characterizing the role of miRNAs in the developing cortex demonstrate the requirement of miRNAs for differentiation of neural progenitor cells starting at embryonic day 12.5 (3). Together, this evidence links the role of miRNAs to neurogenesis and thus this relationship warrants further investigation. Here miRNA …

Modulation Of Hypoglossal Motoneurons By Nitric Oxide, Justin Philip Benoit

Master's Theses

Obstructive sleep apnea (OSA)- the occurrence of repetitive episodes of airway obstruction during sleep- is considered a major health problem affecting up to 9% of adults in the United States (Parish & Somers, 2004). The hypoglossal motor nucleus (HMN) controls genioglossus muscle tone and is critically important for maintaining airway patency; loss of excitatory input to the HMN during sleep results in disfacilitation of hypoglossal motoneurons, increased airway resistance and contributes to the development of OSA (Horner R. L., 2007). However, a fundamental question of sleep medicine that remains unresolved is what mechanisms help maintain airway patency during sleep? A …

Changes In The Proliferation Of The Subventricular Zone Neural Stem Cell Pool Throughout Aging In The Murine Brain, Olayinka Edwards

Honors Scholar Theses

Previous studies regarding subventricular zone (SVZ) neural stem cells (NSCs) have either observed global changes in the SVZ niche containing NSCs or an impure NSC population. By imaging wholemount preparations of mouse brains and staining with molecular markers specific for proliferating NSC nuclei, the study was able to give a more accurate depiction of the SVZ NSC population than its predecessors. This study will quantify the percentage of proliferating NSCs at various ages of adult murine brain development in order to elucidate a possible correlation between NSC division kinetics and the declining neurogenic output witnessed with aging.

Acoustic Cues For Sound Source Distance And Azimuth In Rabbits, A Racquetball And A Rigid Spherical Model, Duck O. Kim, Brian Bishop, Shigeyuki Kuwada

UCHC Articles - Research

There are numerous studies measuring the transfer functions representing signal transformation between a source and each ear canal, i.e., the
head-related transfer functions (HRTFs), for various species. However, only a handful of these address the effects of sound source distance on HRTFs. This
is the first study of HRTFs in the rabbit where the emphasis is on the effects of sound source distance and azimuth on HRTFs. With the rabbit placed in an
anechoic chamber, we made acoustic measurements with miniature microphones placed deep in each ear canal to a sound source at different positions (10–160 cm distance, ±150° azimuth). …

Investigating The Diversity Of Radial Glia Fates In The Rat Neocortex, Abraham William Aron

Honors Scholar Theses

Radial Glia (RG) are a mitotically active population of cells which reside within the ventricular zone at the lateral ventricle and give rise to the pyramidal neurons and astrocytes of the neocortex. Through cellular divisions, RG produce two daughter cells, one which resides in the ventricular zone and becomes another RG while the other is an immature progenitor which migrates away from the ventricle and populates the growing cortex. RG have been found to be a heterogeneous population of cells which express different surface antigens and genetic promoters which may influence the cellular fate of their progeny. In this study …

Oxygen Supplementing, Biocompatible Outer Membranes For Enhanced Performance Of Implantable Glucose Sensors, Hardeep Singh

Honors Scholar Theses

Lack of linearity and sensitivity, oxygen dependence, biofouling and tissue inflammation hinder the development of implantable biosensors for continuous monitoring of glucose. Herein, we report the development of stacked outer membranes based on LBL/PVA hydrogels that improve sensor sensitivity, linearity, oxygen independence and counter biofouling and inflammation. While the inner LBL membrane affords tunable diffusivity, the outer PVA is capable of releasing anti-inflammatory drugs/tissue response modifying agents to counter acute and chronic inflammation, and to induce neo-angiogenesis at the implant site. Sensors were fabricated by immobilizing GOx enzyme on top of 50 μm platinum wires, followed by deposition of stacked …

Dopaminergic Innervation Of The Subventricular Zone In The Murine Brain, Linda Beth Drozdowicz

Honors Scholar Theses

The subventricular zone (SVZ) is one of two areas in the brain that, in a healthy mouse, continually generate neurons throughout adulthood. While it was previously thought that only the A9 neurons of the substantia nigra sent dopaminergic afferents to the SVZ, recent studies suggest that the A10 neurons of the ventral tegmental area may innervate this area. This project has aimed to discover which, if either, model is correct.

Examination of the Aphakia (AK) mouse was used to determine the role of distinct midbrain regions in SVZ regulation. Additionally, intraperitoneal injections of the chemical MPTP were used to deduce …

Effects Of Estrogen On Muscle Damage In Response To An Acute Resistance Exercise Protocol, Megan R. Wolf

Honors Scholar Theses

Creatine Kinase (CK) is used as a measure of exercise-induced muscle membrane damage. During acute eccentric (muscle lengthening) exercise, muscle sarcolemma, sarcoplasmic reticulum, and Z-lines are damaged, thus causing muscle proteins and enzymes to leak into the interstitial fluid.

Strenuous eccentric exercise produces an elevation of oxygen free radicals, which further increases muscle damage. Muscle soreness and fatigue can be attributed to this membrane damage. Estradiol, however, may preserve membrane stability post-exercise (Brancaccio, Maffulli, & Limongelli, 2007; Carter, Dobridge, & Hackney, 2001; Tiidus, 2001). Because estradiol has a similar structure to Vitamin E, which is known to have antioxidant properties, …

Intrinsic Ph-Sensitivity Of Cells In The Retrotrapezoid Nucleus: Possible Role Of Glia In Respiratory Drive, Nicole Edwards

Honors Scholar Theses

An increase in carbon dioxide (CO2) and protons (H+) are the primary signals for breathing. Cells that sense changes in CO2/H+ levels and increase breathing accordingly are located in a region of the caudal medulla oblongata called the retrotrapezoid nucleus (RTN). Specifically, select RTN neurons are intrinsically pH sensitive and send excitatory projections to the respiratory rhythm generator to drive breathing. Glial cells in the RTN are thought to contribute to this respiratory drive, possibly by releasing ATP in response to increases in CO2/H+ levels.

However, pH sensitivity of RTN glial cells has yet to be determined.

Therefore, the goal …

Head And Neck Embryology: An Overview Of Development, Growth And Defect In The Human Fetus, Allison Baylis

Honors Scholar Theses

The purpose of this research is to explore the growth and formation of the head and neck from embryological development through puberty in order to understand how this knowledge is necessary for the development of dental and medical treatments and procedures. This is a necessary aspect of the medical and dental school curriculum at the University of Connecticut Health Center Schools of Medicine and Dental Medicine that needs to be incorporated into the current study of embryology for first-year students. Working with Dr. Christine Niekrash, D.M.D, this paper will cover the embryology and growth of the head, face and oral …

The Role Of Epha4 In Glial Scar Formation Following Injury, Krysti Todd

Honors Scholar Theses

Although many areas of the brain lose their regenerative capacity with age, stem cell niches have been identified in both the subventricular zone (SVZ) along the lateral walls of the lateral ventricles and the subgranular zone (SGZ) of the dentate gyrus (Gage, 2000; Alvarez-Buylla et al., 2001; Alvarez-Buylla and Lim, 2004). The SVZ niche utilizes many mechanisms to determine the migration patterns of neuroblasts along the RMS into the olfactory bulb, one being Eph/ephrin signaling (Conover et al., 2000; Holmberg et al., 2005). EphA4-mediated signaling is necessary for axon guidance during development, and its continued expression in the SVZ niche …

Salivary Cortisol, Psychological Stress And Depressive Symptoms Among Patients Undergoing Colon Cancer Screenings, Allyson Reid

Honors Scholar Theses

As the second leading cause of cancer-related deaths in the United States, colon cancer has a high cure rate if detected early by a colonoscopy (U.S.

Cancer Statistics Working Group, 2007). However, more than 41 million at-risk Americans are not properly receiving colonoscopy screenings according to the recommendations of the Center for Disease Control. This study provides insight into the physiological and psychological benefits of the colonoscopy procedure over and above cancer detection and prevention. Thirty-six patients receiving colonoscopic screening at the University of Connecticut Health Center participated in this study. A questionnaire battery that assessed perceived stress, depressive symptoms, …

Differentiation Of Human Embryonic Stem Cell (Hesc) Derived Pyramidal Neurons, Eagan Jacqueline

Honors Scholar Theses

The mammalian cerebral neocortex is a complex six-layered structure containing multiple types of neurons. Pyramidal neurons of the neocortex are formed during development in an inside-out manner, by which deep layer (DL) neurons are generated first, and upper layer (UL) neurons are generated last. Neurons within the six-layered neocortex express unique markers for their position, showing whether they are subplate, deep layer, upper layer, or Cajal-Retzius neurons. The sequential generation of cortical layers, which exists in vivo, has been partially recapitulated in vitro by differentiation of mouse embryonic stem cells (Gaspard et al., 2008) and human embryonic stem cells (hESC) …

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 …