Neuroscience 2017

Identifying target genes of the homeobox transcription factor Gsx1 in zebrafish |  Zoë A Dobler, Regina L Patrick and Sadie A Bergeron 

Department of Biology, West Virginia University, Morgantown, WV, USA 26506-6057 

GS homeobox 1 (Gsx1) regulates the development of neurons for prepulse inhibition (PPI), a sensorimotor gating phenomenon disrupted in schizophrenia and ASD. However, the molecular genetic pathways underlying the development and function of Gsx1-expressing neurons across the central nervous system are not yet fully understood. Very few Gsx1 target genes have been identified in other model systems. However, they include genes implicated in proliferation, migration, and specification of neural progenitors. We hypothesize that genes implicated in neurodevelopmental disorders with PPI and other sensory processing deficits are targets of Gsx1. In silico analysis identified putative Gsx1 binding sites upstream of zebrafish orthologues of mammalian target genes as well as genes implicated in schizophrenia. We are thus examining the expression of these genes in wild type and gsx1 mutant zebrafish by in situ hybridization. This work will validate that genes regulated by Gsx1 in mammals are conserved in zebrafish, and that genes implicated in schizophrenia are both direct and indirect targets of Gsx1. 

Effects of ambient room temperature fluctuations on C57BL/6 mice on sensori-locomotor behavioral outcomes |  Hana K. Ulman, Jessica M. Povroznik, Elizabeth B. Engler-Chiurazzi, and Candice M. Brown

Departments of Biomedical Engineering, Physiology & Pharmacology, Microbiology, Immunology, and Cell Biology, Health Sciences Center Rodent Behavior Core, Blanchette Rockefellar Neurosciences Institute, and SURI Program, West Virginia University, Morgantown, WV 26506 

In experimental rodents, fluctuations in ambient temperature impact basal physiological measures but less is known about the consequences on functional outcomes. To assess our hypothesis that ambient temperature fluctuations may impact behavioral results, C57BL/6 mice (n=25) were randomized to four temperature groups (59-61, 68-69, 72-74, 78-79 °F) and evaluated using a test battery (body weight, rectal temperature, open field, wire hang, grip strength, rotarod). The effect of portable heaters to ameliorate any behavioral impacts of temperature change was also evaluated. Ultrasonic vocalizations (USV) were recorded to measure temperature-related changes on affective function. Preliminary results suggest highly significant context-specific and sex-dependent differences associated with varying temperatures. Assessment of the number and duration, respectively, of USV revealed significant interactions between ambient temperature and sex ( p=0.001; p=0.03). A significant interaction between sex and temperature was also observed for the wire hang test ( p=0.005). Taken together, these data provide insight into possible temperature-induced variability observed during functional assessment, highlighting the experimental significance of maintaining environmental factors within biomedical research facilities. 

Developmental expression of the non-clustered homeobox genes Gsx1 and Gsx2 in zebrafish |  Rebecca A. Robich, Lindsay C. Fadel, Sarah E. Peterson and Sadie A. Bergeron 

Department of Biology, West Virginia University, Morgantown, WV, USA, 26506-6057 

The closely related genomic screen homeobox genes , gsx1 and gsx2, encode transcription factors that are dynamically expressed throughout the developing central nervous system (CNS). Gsx1 and Gsx2 have coordinate roles in interneuron differentiation and show highly conserved spatiotemporal expression amongst vertebrates. Despite this, neither expression of gsx2, nor the expression of gsx1 or gsx2 across distinct CNS regions in gsx1 or gsx2 mutant zebrafish have been comprehensively analyzed. Consistent with reported expression in the embryonic mouse forebrain, we hypothesize that gsx1 and gsx2 play compensatory roles in the absence of one another through shifts in their normal dorsoventral expression domains. Using RT-PCR and in situ hybridization, we characterized expression of zebrafish gsx2 and found that it starts at the onset of the segmentation period in a domain dorsal to gsx1. gsx2 expression is restricted to the ventral diencephalon, telencephalon, caudal hindbrain, and spinal cord. Further investigation of the expression of gsx1 and gsx2 in mutants will elucidate the roles of these conserved and closely related transcription factors in neural development across the CNS. 

Examining visual neural circuit development and behavior in gsx1 mutant zebrafish 

Rebekah Shephard1, Regina L Patrick1, Qing Bai2, Enhua Shao2, Edward A Burton2, Sadie A Bergeron1 

1 Department of Biology, West Virginia University, Morgantown, WV 26506 and 2 University of Pittsburgh, Department of Neurology, Pittsburgh, PA 15213 

Proper vision depends on the correct formation of neural circuits between the eyes and brain. Such visual ability can be assessed by measuring the optokinetic response (OKR), saccadic eye movements that stabilize retinal images while an organism is in motion. Additionally, gs homeobox 1 ( gsx1) is expressed in many developing brain regions, including the pretectum and optic tectum in zebrafish. However its role in the development of visual neural circuits has not been examined. We hypothesize that visually guided behavior and its corresponding neuroanatomy will be disrupted in gsx1 zebrafish mutants. By 6 days post fertilization in the pretectum, gsx1 mutant zebrafish have neurons as demarcated by anti-HuC/HuD antibody but lack normal glutamate expression. Additionally, the OKR of gsx1 mutant larvae is impaired in our preliminary analyses. We continue to analyze axon connections to and neurotransmitter identity of neurons in the pretectum in gsx1 mutant zebrafish using transgenic lines and immunolabeling. These studies will reveal novel roles for gsx1 in the development and function of visual circuits. 

Knockdown of the serotonin 2B receptor expression in olfactory receptor neurons of Drosophila |  Andrew M. Steele and Andrew M. Dacks 

Department of Biology, West Virginia University, Morgantown, West Virginia 26506 

Serotonin (5-HT) is a neurotransmitter that has multiple sources throughout the body of organisms. 5-HT has many important roles in neurological function, and many diseases arise from impairments in these 5-HT-related functions. 5-HT derives from multiple sources, but it is difficult to separate the influences of each 5-HT source from another. For this project, we used the Drosophila olfactory system to determine the effects of blood-borne serotonin on odor coding via the olfactory receptor neurons (ORNs). Fruit flies detect odors with ORNs, which have a single serotonin receptor subtype called the 5-HT2B receptor. 5-HT can be either blood-borne or released in the brain, yet ORNs are likely to be only affected by blood-borne 5-HT. To look at the consequences of blood-borne serotonin on the peripheral nervous system (olfactory processing), we knocked-down the expression of the 5-HT2B receptor in the ORNs using a genetic tool and tested behavior using olfactory sensitivity experiments. Since the 5-HT2B receptor is excitatory, we predict that this will cause a lack of excitation in the ORNs, and therefore decrease sensitivity in the flies 

Regulation of physiological responses and social stress: the effects of compassion meditation during stress paradigms in virtual reality |  Karianne K. Sretavan Wong, Nanda K. Silva, Noor O. Qazi, Helen R. Melnick and Julie Brefczynski-Lewis 

1 University of Rochester, Rochester, NY, 2 West Virginia University, Morgantown, WV and 3 Bluefield State College, Bluefield, WV 

Social conflict can be a source of severe stress and anxiety, and virtual reality (VR) could serve as a valuable tool to study such psychosocial interactions, providing advantages to live interaction such as variable and environmental control. It is unknown whether VR interactions can illicit similar physiological responses, or whether pro-social training techniques can translate to the virtual world. In this study, we examined responses during stress-inducing social confrontation in a virtual versus real environment, and tested whether responses changed with Compassion training. Subjects and trained confederates interacted in the form of 3 minute structured vignettes, while physiological responses (heart rate (HR), blood pressure (BP)) were measured. A subset of participants took part in a post-training interaction as well as a functional magnetic resonance imaging (fMRI) study to test brain responses to faces of the real and virtual disliked and neutral persons from the study (confederates) and real life. For the physiological study, early results confirm that VR and real interactions yielded comparable stress responses ( t-test differences: systolic BP p=0.502, diastolic BP p=0.074, HR p=0.253). We hypothesize that fMRI results (still in collection) will further confirm a lack of difference between VR vs. live stress interactions, and that stress-induced physiological and brain activation will be dampened by compassion mediation. Such results would have implications for conflict training and stress management techniques. 

Lipopolysaccharide-induced neuroinflammation is associated with increased depressive-like behavior |  Kristen Pechacek and Cole Vonder Haar 

Department of Psychology, West Virginia University, Morgantown, WV 26506 

A common symptom of a traumatic brain injury is neuroinflammation, which has also been associated with depressive-like behaviors. Lipopolysaccharide (LPS) is a component of gram-negative bacteria that has been shown to cause activation of microglia and produce inflammatory cytokines when an animal is exposed to it. The current study investigated the effects of neuroinflammation caused by LPS on motivational behavior in rats. The progressive ratio task was used to assess the strength of these behaviors. After obtaining a stable baseline of behavior, (~30 sessions), rats received either acute doses (i.p. injection) or chronic administration (subcutaneous pump) and were re-assessed for behavioral changes. After dosages of 2mg/kg and 1mg/kg, a decrease in behavioral performance was shown. LPS administration resulted in reduced motivation, suggesting a major role for inflammation in depression. 

Department of Physiology, Pharmacology, and Neuroscience, Neuroscience Graduate Program,  West Virginia University Summer Undergraduate Research Internship (WVU SURI), Blanchette Rockefeller Neurosciences Institute, West Virginia University, Morgantown, WV 26506 

Two populations of neurons are essential for proper function of the cerebral cortex: glutamatergic excitatory neurons and GABAergic inhibitory interneurons. During development, these neurons migrate into the cortex from different locations and establish connections with one another that provide the foundation for brain function throughout life. Disruptions to these processes have been linked to disorders like autism, epilepsy, and schizophrenia. To understand how these disorders arise, we must first learn how excitatory and inhibitory neurons interact. Previously, our lab has found a role for the c-Jun N-terminal kinase (JNK) pathway in the migration of cortical interneurons. Here, we explore how the complete loss of JNK function from interneurons can disrupt excitatory neurons. We use acute pulse experiments with thymidine analogs to quantify cell cycle kinetics of cortical progenitor cells, and pulse-chase experiments to follow the migration of excitatory neurons born at two embryonic time points. These experiments will reveal whether loss of JNK signaling in interneurons impacts the proliferation and migration of excitatory neurons and provide insight into cell-cell interactions in the developing cerebral cortex. 

miR-34a targets Cytochrome C and shapes stroke outcomes |  Edward A. P. Provencher, Heng Hu1, Stephanie Rellick, Imran Farooqi, Saumyendra N. Sarkar, Kimberly Grasmick and Xuefang Ren. 

Department of Physiology and Pharmacology, Department of Microbiology, Immunology, and Cell Biology and Experimental Stroke Core, Center for Basic and Translational Stroke Research, West Virginia University, Morgantown, WV 26506 

The blood-brain barrier (BBB) is a crucial interface between the central nervous system (CNS) and the circulatory system that maintains cerebral homeostasis by selectively allowing entry of blood solutes into the CNS. BBB dysfunction has been observed in neurodegenerative disorders such as stroke, and this has negative impacts on stroke outcomes. Mitochondria are key players in this process. We recently demonstrated that miR-34a regulates the BBB by targeting cytochrome c (CYC) in vitro. Using a murine transient middle cerebral artery occlusion model, we demonstrate elevated miR-34a expression in serum and primary endothelial cells (CECs) from stroke mice. We report that miR-34a deficiency significantly reduces BBB permeability, improving stroke outcomes. CYC is decreased in the ischemic hemisphere from wild-type but not miR-34a-/- mice following stroke reperfusion. Uncoupling of electron flow by the pharmacological inhibitor carbonyl-cyanide-4-(trifuoromethoxy)phenylhydrazone compromises mitochondrial oxidative phosphorylation in cultured CECs and worsens infarct volume in stroke mice. Our study suggests that miR-34a is a critical regulator in BBB permeability and mitochondria, and targeting miR-34a may be a potential therapeutic strategy for stroke. 

Categorical vs. graded perception of communication signals in weakly electric fish |  Olivia Hill, Julie Closson and Gary Marsat 

Department of Biology, West Virginia University, Morgantown, WV 26506 

Electric fish are very helpful in researching the physiology of the sensory and central nervous system. Recent evidences indicated that at both the neural and behavioral levels, weakly electric fish’s communication signals -namely chirps- can be processed either to discriminate specific details in the signals or, on the contrary, only allow for the detection of the signal. In this study we ask whether these different processing strategies, categorical perception versus graded perception, are observed across related species of electric fish. Perceptual abilities of three species of Apteronotids was compared by submitting them to a habituation-dishabituation behavioral test. Our results indicate that some species perceive their communication signals primarily in a categorical, detection manner, while other species have the ability to discriminate fine variation, such as elapsed time, in the signals. We discuss how species-specific difference in communication signals structure and social behavior could explain our results. 

Positive allosteric modulation of CB 1 attenuates Δ 9 -THC withdrawal 

Emily Silvestri, Kristen R Trexler, Hunter Aliff, Sara R Nass, Matthew L Eckard  and Steven G Kinsey 

University of New Hampshire, Durham, NH 03824, West Virginia University, Morgantown, WV 26506 and West Virginia State University, Institute, WV 25112 

Although cannabis withdrawal is characterized by drug craving, sleep disturbances, and changes in emotion, animal models focus almost exclusively on somatic withdrawal signs. In the present study, in addition to somatic signs, multiple behaviors relating to motivation and emotion were also evaluated, with the goal of better modeling human cannabis withdrawal symptoms. ZCZ011 is a CB1 cannabinoid receptor positive allosteric modulator (PAM) that increases the activity of CB1 agonists. We hypothesized that ZCZ011 attenuates THC withdrawal in mice. Mice were treated with THC (10 mg/kg, s.c.) or vehicle for 6 days, and withdrawal was precipitated using the CB1 antagonist rimonabant (3 mg/kg, i.p.). ZCZ011 (40 mg/kg, i.p.) significantly attenuated somatic withdrawal but had no effect on marble burying or struggling in the tail suspension test. ZCZ011 dose-dependently induced immobility. Results of this study indicate that ZCZ011 blocks THC withdrawal-induced somatic withdrawal signs, but sedation may be a confound when using higher doses. Positive allosteric modulation of CB1 is a novel strategy to reduce cannabis dependence. 

Neuroscience Poster 12: 

Modeling kinematics and dynamics of movement from transcranial magnetic stimulation data 

Brian W. Donaldson, Russell L. Hardesty, Bradley S. Pollard and Valeriya Gritsenko 

Department of Human Performance and Applied Exercise Science, Division of Physical Therapy, West Virginia University School of Medicine, Morgantown, WV 26506 

The central nervous system and its control over limb movement are currently being investigated to understand how the brain achieves accurate movements under diverse dynamic conditions. Thus, gaining knowledge in limb dynamics of the musculoskeletal system using quantification methods may be beneficial in understanding neurological control of the limb in both healthy and pathological states. In this study, inverse kinematics and dynamics models of the arm were constructed using Matlab’s Simscape Multibody to approximate kinematics and dynamics of arm movement. Experiment participants were defined specific movements to execute while under stimulation of the motor cortex from transcranial magnetic stimulation (TMS). The recorded motion capture data was simulated through the inverse kinematics model to provide joint angles for specific arm joints. These joint angles were subsequently simulated through the inverse dynamics model to provide torques of the joints. Preliminary results have successfully approximated joint angles and torques that appear consistent with subject movement. Full comprehension of these limb dynamics through modeling may be useful for clinical applications involving prosthetics or neurological impairments. 

Serotonin and its role in olfactory sensory-driven behavior in Drosophila melanogaster 

Reid R. Strobl and Andrew M. Dacks 

Department of Biology, West Virginia University, Morgantown, WV 26506 

Serotonin is an important neurotransmitter used by almost all animals. It is of great behavioral relevance, as it has been linked to modulating things such as mood, gastrointestinal activity, memory, and even sleep. As there are many behavioral conditions that result from improper serotonin signaling, it is important for us to investigate the role of serotonin in the brain, and how it modulates neural networks. Unfortunately, serotonergic systems in mammalian models are far too complex to study how individual classes of serotonergic neurons function. Drosophila is a great model system to study the effects of serotonin on olfaction, as we can specifically target the only two neurons that supply serotonin to the primary olfactory processing center, the CSD neurons. By comparing normal fly behavior to flies with upregulated and downregulated CSD signal, the function of serotonergic modulation in olfactory processing can potentially be deduced. While data collection is ongoing, it suggests that serotonergic modulation of olfaction might play a role in increasing odorant sensitivity under highly concentrated odor conditions. 

Low-dose wearable PET imaging during ambulatory motion in humans |  Nanda Siva, Julie Brefczynski-Lewis, Chris Bauer, Alexander Stolin, Gary Marano, Mary Beth Mandich, Thorsten Wuest, Samantha Melroy and Stan Majewski 

Department of Physiology and Pharmacology, Blanchette Rockefeller Neurosciences Institute, Department of Radiology, Department of Biomedical Engineering, Department of Physical Therapy, and Department of Industrial Management Systems, West Virginia University, Morgantown, WV 26506 

A goal in neuroscience is understanding human brain behavior during everyday situations; however, current imaging modalities are ineffective at representing deep brain structures during motion. Thus, our group has developed a wearable Positron Emission Tomography(PET) brain scanner, co-registered with human head movement, that measures metabolic activity levels in different brain regions. The imager consists of 12 silicon photomultiplier modules in a lightweight 21 cm ring and requires a low dose F18-FDG (glucose-analog). In this study, brain images taken while patients were performing simple physical tasks (such as walking in place or tapping their foot) display noticeable activity differences in the basal ganglia, thalamus, and occipital lobe. Additionally, analysis of dynamic PET data shows the uptake of glucose over time. Future investigation will involve comparison of produced images to patients’ clinical PET scans and imaging of subjects participating in social interactions. The scanner has potential applications in medical research, for instance monitoring brain plasticity during patient stroke recovery or diagnosing/evaluating brains of patients who struggle to remain stationary such as those with dementia or epilepsy.