Master of Arts, Case Western Reserve University, 2017, Psychology

Sexual assault is unfortunately a common form of interpersonal violence that confers considerable risk for negative psychological and physical outcomes. However, the prevalence and associated sequelae of sexual assault are understudied in key at risk groups like inner city and low-income populations. Using a subset of a large epidemiological sample comprised of 8,533 highly traumatized, low-income African American men and women, the current study examines the prevalence of sexual assault and a range of associated health outcomes among sexual assault survivors. Results indicate nearly 40% experienced sexual assault, primarily in childhood. Associated negative health outcomes include PTSD, Depression, self-harm, substance use, incarceration, and increased trauma exposure, among others. In a translational paradigm conducted on a subset (n=241), dark-enhanced startle yielded no differences between groups, however sexual assault was associated with habituation deficits.

Committee: Norah Feeny PhD (Committee Chair); Lee Thompson PhD (Committee Member); Arin Connel PhD (Committee Member) Subjects: Psychology

PHD, Kent State University, 2015, College of Arts and Sciences / School of Biomedical Sciences

Longenecker, Ryan J, Ph.D., December 2015 DIFFERENTIAL PATHOLOGIES RESULTING FROM SOUND EXPOSURE: TINNITUS VS HEARING LOSS (104 pp.)Director of Dissertation: Alexander V. Galazyuk, Ph.D. The first step in identifying the mechanism(s) responsible for tinnitus development would be to discover a neural correlate that is differentially expressed in tinnitus-positive compared to tinnitus negative animals. Previous research has identified several neural correlates of tinnitus in animals that have tested positive for tinnitus. However it is unknown whether all or some of these correlates are linked to tinnitus or if they are a byproduct of hearing loss, a common outcome of tinnitus induction. Abnormally high spontaneous activity has frequently been linked to tinnitus. However, while some studies demonstrate that hyperactivity positively correlates with behavioral evidence of tinnitus, others show that when all animals develop hyperactivity to sound exposure, not all exposed animals show evidence of tinnitus. My working hypothesis is that certain aspects of hyperactivity are linked to tinnitus while other aspects are linked to hearing loss. The first specific aim utilized the gap induced prepulse inhibition of the acoustic startle reflex (GIPAS) to monitor the development of tinnitus in CBA/CaJ mice during one year following sound exposure. Immediately after sound exposure, GIPAS testing revealed widespread gap detection deficits across all frequencies, which was likely due to temporary threshold shifts. However, three months after sound exposure these deficits were limited to a narrow frequency band and were consistently detected up to one year after exposure. This suggests the development of chronic tinnitus is a long lasting and highly dynamic process. The second specific aim assessed hearing loss in sound exposed mice using several techniques. Acoustic brainstem responses recorded initially after sound exposure reveal large magnitude deficits in all exposed mi (open full item for complete abstract)

Committee: Alexander Galazyuk Ph.D. (Advisor); Jeffrey Wenstrup Ph.D. (Committee Member); Yong Lu Ph.D. (Committee Member); Angelo DeLucia Ph.D. (Committee Member); Gary Koski Ph.D. (Committee Member) Subjects: Acoustics; Behavioral Sciences; Biomedical Research; Neurobiology; Neurosciences

BS, Kent State University, 2011, College of Arts and Sciences / Department of Biological Sciences

Oxytocin (Oxt) is a nine amino acid neuropeptide that has been studied for its role in social cognition and social behavior across species. To date, a single subtype of Oxt receptor, the Oxtr, has been identified. Oxt has also been implicated in several neuropsychiatric disorders including schizophrenia. One characteristic of schizophrenia is impaired sensorimotor gating, which is the ability to properly filter or “gate” sensory information. Across species, deficits in sensorimotor gating are measured using prepulse inhibition (PPI) of the startle reflex. PPI is the reduction in startle magnitude when a startling pulse is preceded by a smaller prepulse. In the current study we used conditional Oxtr knockout mice, where the disruption was specific to forebrain Oxtr (Oxtr FB/FB). Based on previous work in Oxt knockout mice, which have increased phencyclidine (PCP)-disrupted PPI, we hypothesized that treatment with psychotomimetics would result in greater PPI disruption in Oxtr FB/FB mice compared to wildtype (Oxtr +/+) controls. We used male and female Oxtr +/+ and Oxtr FB/FB mice and tested their PPI following treatment with the psychotomimetics: amphetamine (Amp), apomorphine (Apo), and PCP. We found that Oxtr FB/FB mice did not have significant differences in the disruption of PPI compared to Oxtr +/+ mice. This lack of effect cannot be attributed to an overall genotypic difference in PPI, as baseline testing found no differences in PPI between Oxtr +/+ and Oxtr FB/FB mice. In conclusion, our data suggest that Oxt signaling in the forebrain does not interact with PPI circuitry.

Committee: Heather Caldwell PhD (Advisor); Eric Mintz PhD (Committee Member); Manfred van Dulmen PhD (Committee Member); Chi-Hua Chiu PhD (Committee Member) Subjects: Neurosciences

MS, Kent State University, 2009, College of Arts and Sciences / School of Biomedical Sciences

Oxytocin (Oxt) is a nonapeptide synthesized in the magnocellular neurons of the paraventricular (PVN) and supraoptic (SON) nuclei of the hypothalamus and it is released to the periphery from axon terminals. Numerous studies indicate that Oxt plays an important role in cognition and social behavior. Abnormalities in the Oxt system have also been implicated in several neuropsychiatric disorders such as schizophrenia, obsessive compulsive disorder (OCD) and Tourette's syndrome. Patients diagnosed with these disorders show deficits in a fundamental form of information filtering known as sensorimotor gating. Sensorimotor gating can be measured across species using prepulse inhibition (PPI) of the startle reflex. PPI can be disrupted by treating animals with dopamine receptor agonists (e.g. apomorphine and amphetamine) and NMDA receptor antagonists (e.g. phencyclidine (PCP) and MK-801). Previous studies suggest that Oxt may act as a natural antipsychotic and our lab has shown that Oxt knockout mice (Oxt-/-) are more susceptible to the psychosis-related effects of PCP. So, to further characterize the role of the Oxt system in sensorimotor gating deficits, a rescue experiment was performed by pretreating mice with Oxt prior to administering PCP. We found that pretreatment with Oxt appears to cause a partial rescue of the PPI-disrupting effects of PCP in male Oxt-/- mice. As the actions of Oxt are mediated via binding to the Oxt receptor, pharmacologically disrupted PPI was examined in mice lacking the Oxt receptor (Oxtr-/-). We found that treatment with apomorphine, amphetamine and MK-801 equally disrupted PPI in wildtype and Oxtr-/- mice. Our data suggest that in Oxtr-/- mice the neurocircuitry involved in the regulation of PPI might be normal. Overall, these results indicate that the Oxt/Oxtr system plays an important role in social behavior and may have important implications in human behavioral disruptions.

Committee: Heather Caldwell PhD (Advisor); Eric Mintz PhD (Committee Member); Sean Veney PhD (Committee Member) Subjects: Biomedical Research