Abstract List for 2019 meeting

#551: Bridging the gap from genes to behavior in autism spectrum disorders

Auerbach, Benjamin D ;

Center for Hearing and Deafness, SUNY University at Buffalo, College of Arts and Sciences;

Shared pathological mechanisms have been identified across diverse models of autism spectrum disorders (ASD), suggesting the potential for canonical disruptions. The challenge now is to determine how these disruptions interact across levels of neuronal function to ultimately give rise to the diverse behavioral and neurological phenotypes associated with ASD. Bridging this gap requires tractable yet disease-relevant behavioral models in combination with an integrative experimental approach that spans multiple levels of analysis. Abnormal sensory processing is a hallmark of ASD and related neurodevelopmental disorders like Fragile X syndrome (FX), most notably manifesting as extreme sensitivity to sound. Auditory hypersensitivity is not only an important clinical problem in ASD, but it also likely reflects fundamental circuit defects that will extend to more complex but less accessible features of the disorder, such as impaired communication and social behavior. We have developed novel behavioral assays for assessing sound sensitivity in rodents and applied them to a recently developed Fmr1 KO rat model of FX. We found robust evidence for excessive loudness perception and decreased tolerance in Fmr1 KO rats. By combining these behavioral assays with high-density in vivo electrophysiological recordings from multiple points along the auditory pathway, we found that auditory hypersensitivity coincided with sound-evoked hyperactivity and hyperconnectivity in a cortical-amygdala auditory network despite normal, or perhaps even diminished, subcortical drive. This novel symptoms-to-circuit approach has the potential to uncover recurring pathophysiological motifs that will generalize across brain areas and cognitive domains affected in ASD. At the same time, these results have direct clinical implications for one of the most common and disruptive sensory impairments in FX and ASD.

#589: GSK3β phosphorylation disrupts kinesin function during axonal transport

Banerjee, Rupkatha ; Day, Tierney ; Yu, Michael ; Gunawardena, Shermali ;

Department of Biological Sciences, SUNY University at Buffalo, College of Arts and Sciences;

Axonal transport is aided by motor proteins, Kinesin and Dynein on long microtubule tracks (MTs). One possible mechanism by which transport defects could occur is by improper regulation of molecular motors. Our previous work showed that presenilin (PS), a protein involved in Alzheimer’s disease, and Glycogen synthase kinase 3β (GSK3β) can function as regulators of axonal transport. Reduction of GSK3β or PS, stimulated the in vivo motility of amyloid precursor protein (APP) containing vesicles, while excess active-GSK3β inhibited motility. PS and GSK3β functionally interacted during axonal transport, with the loop region of PS rescuing GSK3β-mediated transport defects. Therefore, we propose a model in which during normal transport GSK3β and kinesin are associated, and the loop region of PS acts as a scaffold to take GSK3β away from kinesin. Indeed, we found that active GSK3β associated with and phosphorylated kinesin in vitro. We identified one site on kinesin that was modified by GSK3β. Interestingly, the GSK3β phospho-defective form of kinesin abolished motility but did not affect MT binding, while the GSK3β phospho-mimicking form of kinesin abolished both MT binding and motility. Therefore, our observations suggest that GSK3β phosphorylation can turn off kinesin motor activity perhaps by releasing kinesin from MTs. These findings highlight the complex regulatory mechanisms that exist for motor function during axonal transport in vivo.

#592: Studying the Effects of NRMT1 Loss on Brain Function

Catlin, James ¹; Rein, Benjamin ²; Yan, Zhen ²; Schaner Tooley, Christine ¹;

¹Department of Biochemistry, ²Department of Physiology and Biophysics, SUNY University at Buffalo, School of Medicine and Biomedical Sciences;

N-terminal RCC1 methyltransferase 1 (NRMT1) is the first known eukaryotic N-terminal methyltransferase. It is a highly conserved enzyme that can mono-, di-, and trimethylate proteins on their alpha-amino group. It has a highly conserved X-Pro-Lys/Arg N-terminal consensus sequence, which predicts over 300 potential substrates. To study the effects of loss of this enzyme in vivo, a NRMT1 knockout (NRMT1^-/-) mouse was created. Broad characterization of these animals revealed phenotypes associated with premature aging such as premature graying, fibrotic skin, female-specific infertility, kyphosis, and shortened lifespan. To further determine how NRMT1 loss affects the brain, behavioral characterization has revealed age-specific spatial learning and memory loss in the Barnes maze test. Assessment of general locomotor activity in the Open field task has also revealed hyperactivity in the knockouts seen as early as 6 weeks. Histological characterization of NRMT1^-/- mice has revealed postnatal enlargement of the lateral ventricles, as well as age-dependent degeneration of the dentate gyrus (DG). Further determination of NRMT1’s expression throughout the brain, its cell type specificity, and its regulation of brain-specific targets will continue to elucidate the function of NRMT1 in the brain.

#574: Unraveling the role of SUMOylation in peripheral myelination

Frick, Luciana R ;

Department of Neurology, SUNY University at Buffalo;

The mechanisms that govern myelination in the peripheral nervous system are not completely understood. Post-translational modifications of proteins are necessary for peripheral myelination, and malfunction of these pathways leads to neuropathies. Whether SUMOylation, covalent attachment of Small Ubiquitin-like Modifier (SUMO) proteins to the substrate, is involved in the formation of myelin and/or in the pathophysiology of peripheral neuropathies is not known. We have recently identified SUMO2 as a novel protein that may be involved in the early interaction between axons and Schwann cells. In the pseudopod system, Schwann cells are cultured on a porous surface, and stimulated to extend pseudopods towards a neuronal membrane preparation. One of the proteins found in the proteome of Schwann cell pseudopods is SUMO2, along with 10 immediate neighbors in the interactome. Using a prediction algorithm, we evaluated which of the proteins found in the pseudopods have SUMO interaction motifs (SIMs) and/or SUMOylation sites. Interestingly over 85% of those proteins have either SIMs or SUMOylation sites: 67% of proteins may be SUMOylable, 58% of the proteins may interact with SUMO through SIMs. Proteins involved in cytoskeleton organization represent the major category of enriched proteins bearing SIMs and/or SUMOylation sites, and proteins related to regulation of cellular component organization are the most significantly enriched in pseudopods. Pharmacological modulation of SUMOylation and gene targeting of SUMO proteins affect myelination and Schwann cell survival in vitro. Our current research is focused on the role of SUMOylation, its substrates, and SUMO2 in peripheral myelination during development and in mouse models of demyelinating diseases.

#604: Predictions from structural and functional connectivity for cognitive rehabilitation outcomes in MS

Fuchs, Tom A ¹; Ziccardi, Stefano ²; Benedict, Ralph H B¹; Bartnik, Alexander ¹; Kuceyeski, Amy ³; Charvet, Leigh E ⁴; Oship, Devon ¹; Weinstock-Guttman, Bianca ¹; Wojcik, Curtis ¹; Hojnacki, David ¹; Kolb, Channa ¹; Escobar, Jose ¹; Campbell, Rebecca ¹; Duc Tran, Hoan ¹; Bergsland, Niels ¹; Jakimovski, Dejan ¹; Zivadinov, Robert ¹; Dwyer, Michael G ¹;

¹Department of Neurology, SUNY University at Buffalo, School of Medicine and Biomedical Sciences; ²Department of Neurology, University of Verona, Italy; ³Brain and Mind Research Institute, Weill Cornell Medical College; ⁴Department of Neurology, NYU School of Medicine;

Background: Patient profiles of functional connectivity are associated with cognitive reserve and moderate the structure-cognition relationship in people with multiple sclerosis (PwMS). Such interactions may also relate to potential for building cognitive reserve, such as with restorative cognitive rehabilitation, whose efficacy can be predicted from baseline patient factors.  
Objective:  To determine whether patient response to restorative cognitive rehabilitation is predictable from baseline structural network disruption and whether this relationship is moderated by functional connectivity.
Methods: For this single-arm repeated measures study, we recruited 25 PwMS for a 12-week program. Following MRI, participants were tested using the Symbol Digit Modalities Test (SDMT) pre- and post-rehabilitation. Baseline patterns of structural and functional connectivity were characterized relative to healthy controls.
Results:  Lower white matter tract disruption in a network of region-pairs centered on the precuneus and posterior cingulate (default-mode network regions) predicted greater post-rehabilitation SDMT improvement (p=0.048). This relationship was moderated by profiles of functional connectivity (β=-0.415, p=0.022), revealing four groups of subjects with predictably varying response to rehabilitation.
Conclusion: The relationship between baseline structural network disruption and response to restorative cognitive rehabilitation is moderated by patient

#607: Nicotine enhances reinstatement elicited by a discriminative stimulus signaling alcohol availability

Angelyn, Hailley ; Meyer, Paul J ;

Department of Psychology, SUNY University at Buffalo;

Nicotine may increase the susceptibility for alcohol intake and relapse by invigorating the behavioral response to alcohol-cues. Indeed, nicotine can amplify the behavioral response to discrete cues that have been explicitly paired with the receipt of alcohol. It is unknown, however, whether nicotine also invigorates the behavioral response to higher-order cues that signal reward availability called “discriminative stimuli”. Because discrete cues and discriminative stimuli engage different psychological processes, it cannot be assumed that nicotine affects the behavioral response to both cues. Therefore, we investigated whether nicotine enhances the response to a discriminative stimulus (DS) as assessed by an alcohol-seeking reinstatement test. Male, Long-Evans rats (n = 35) were exposed to alcohol in their home-cages. Rats then underwent self-administration in which nosepokes into an active port during the ‘drug-available’ or DS period resulted in free-access to a sipper-bottle containing ethanol (14% v/v) for 30-s. Responses into the inactive port during the DS period, as well as responses into either port during the ‘drug-unavailable’ or no-DS period were of no consequence. Rats then underwent extinction, in which the DS was not presented and responses had no consequence, followed by reinstatement. During reinstatement, the DS was displayed but responses were not reinforced. Rats received nicotine (0.4mg/kg s.c.) or saline injections in a 2x2 design during self-administration and reinstatement. Reinstatement was defined as an increase in active port entries during DS presentations, relative to active port entries on the last day of extinction. Although reinstatement occurred in all groups that received nicotine at least at one time-point, rats that received nicotine during both self-administration and reinstatement demonstrated the greatest reinstatement.Thus, nicotine may contribute to relapse to alcohol use by augmenting the cognitive expectation of alcohol.

#593: Prepubertal ovarian inhibition of exploration and novelty seeking in Siberian hamsters

Barrett, Abigal R ; Kyne, Robert F ; Brown, Lauren M ; Lawton-Stone, Tamijah ; Schatz, Kelcie C ; Paul, Matthew J ;

Department of Psychology, SUNY University at Buffalo, College of Arts and Sciences;

The overwhelming majority of research on the role of gonadal hormones in behavioral development has focused on perinatal, pubertal, or adult life stages.  The juvenile period has been overlooked because it is thought to be a time of gonadal quiescence. We tested whether prepubertal gonadectomy at postnatal day (P)15 impacts the behavior of male and female juvenile hamsters on the Light/Dark Box, Novel Object, and Social Approach tests at P30 and compared these findings to those obtained after adult gonadectomy (surgery conducted at ~P80 and behavior testing at ~P106). Prepubertal ovariectomy increased exploration and novel object investigation of juveniles indicating an inhibitory role for the juvenile ovary; social approach was unaffected. In contrast, adult ovariectomy and castration (both prepubertal and adult) had no effect on any behavioral measure. These findings suggest that ovarian inhibition of exploration and novelty seeking is restricted to the juvenile phase. We then tested whether rearing hamsters in a short day length (SD), which delays puberty in this species, extends the interval of juvenile ovarian inhibition on exploration and novelty seeking. We also tested whether provision of estradiol reverses the effects of prepubertal ovariectomy. SD-reared hamsters were gonadectomized or sham-operated and provided with blank, cholesterol, or estradiol capsules at ~P80 and underwent behavioral testing at ~P106. Ovariectomy increased exploration in the SD-reared juveniles despite the older age of surgery and testing. Estradiol treatment had no effect. These findings reveal a novel inhibitory role for the juvenile ovary in exploration and novelty seeking and suggest that estradiol on its own is not sufficient to mediate these inhibitory actions. Ongoing experiments administering letrozole to long day-reared juvenile Siberian hamsters are testing whether estradiol is necessary for juvenile ovarian inhibition of Light/Dark Box exploration.

#608: Increasing Microtubule Acetylation Inhibits Axon Growth : A Role for EB3

Belfatto, Anthony ; Cornell, Brain ; Len, Sui ; Sindoni, Michael ; Hogan, Elizabeth ;

Biology Department, Canisius College;

The process of growth cone advance requires a transition between dynamic, deacetylated microtubules (MTs) in the peripheral domain and stable, acetylated MTs (AcMT) in the axon. Our previous research suggested that decreasing AcMT levels in the axon accelerates growth cone advance by promoting advancement of dynamic MTs into the leading edge of growth cones. To increase the amount of acetylated microtubules (AcMTs), we used tubacin, a cell-permeable inhibitor of HDAC6, an enzyme that removes acetyl groups from MTs. Western blot analysis showed exposure of snail ganglia to tubacin increased levels of microtubule acetylation. Rat embryonic neurons exposed to tubacin showed a two-fold reduction in axon growth, which was similar to our findings in snail neurons. These results suggest modifying microtubule acetylation may be a common strategy to regulate axon growth in both vertebrates and invertebrates. We next tested whether increasing microtubule acetylation would affect the localization of EB3, a microtubule plus-end tracking protein. Quantification of fluorescent intensity in neurons exposed to tubacin showed a significant increase in the amount of EB3 present in the filopodia and a decreased level in the peripheral domain of growth cones compared to untreated neurons. These results suggest that microtubule acetylation promotes redistribution of EB3, resulting in suppression of EB3 interactions with microtubules.

#572: Development of bidirectional 'mini-brain' computer interface modulate functional neural circuits

Bhattacharya, Mahasweta ¹; Augustyniak , Justyna ²; Liput, Michal ²; Stachowiak, Ewa ²; Stachowiak, Michal K ²; Dutta, Anirban K ¹;

¹Department of Biomedical Engineering, ²Pathology and Anatomical Sciences, SUNY University at Buffalo;

INTRODUCTION Electrophysiology is a powerful technique in deciphering functional microcircuits. In this exploratory work, we developed a bidirectional recording system using tetrodes and Intan RHD2132 amplifier board for cerebral organoids. We hypothesized that electrophysiological responses from activated neurons near recording electrodes would reveal neuronal circuit maturity. Furthermore, stimulation-based evoked response can provide deeper understanding. Besides, recording from both healthy control and schizophrenic organoid can elucidate the understanding of electrophysiological aspect in schizophrenia. METHODS Six sample sets of cerebral organoids were cultured using iPSCs. Recording was performed on three-month-old, healthy control(23 days,48 days), schizophrenia(34days)(control and treated) organoids. We recorded using polyimide-coated nickel-chrome tetrode wire. Using 8 tetrodes, we successfully recorded from 32 channels with each tetrode (diameter: 50μm). This method was advantageous in obtaining electrical signals from maximum area of the cerebral organoid by targeting significant number of neural rosettes. We conducted spike detection using open-source hardware Open-ephys where we got promising spontaneous neural activity from the 3-month-old organoid. RESULTS Spike detection algorithm followed by clustering is performed on the electrophysiological data obtained from recording to find out correlation in spikes. Recording from 48-day old organoid showed correlated data. DISCUSSION We showed that continuous online monitoring of tetrode spike data is feasible to detect neuronal activity however correlated data indicated weak connections and lack of circuit maturation in the 48day old organoid whereas significant maturation and spontaneous activity was found in the 3month old organoid. Furthermore, in the mBCI, spontaneous activity triggered stimulation is possible with our mBCI to guide microcircuit maturation as future work.

#599: Decoding the olfactory tubercle dopamine circuit via electrochemical and genetic techniques

Bhimani, Rohan V ¹; Park, Jinwoo ²;

¹Neuroscience, ²Biotechnical and Clinical Laboratory Sciences , SUNY University at Buffalo, School of Medicine and Biomedical Sciences;

The olfactory tubercle (OT), a limbic structure located at the ventral most part of the ventral striatum, receive dense dopamine (DA) innervation from the ventral tegmental area (VTA) and plays a pivotal role in the reinforcing effects of drugs of abuse. However, due to its anatomical location and proximity to neighboring DA rich brain structures (e.g. nucleus accumbens, caudate putamen), functional characterization of OT-DA has been overshadowed. In order to overcome such challenges, recent techniques, such as Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) and optogenetics, have facilitated the understanding of the roles of complex brain circuits. In this study, we used a viral targeting system to restrict DREADD expression to VTA-DA neurons and employed in vivofast-scan cyclic voltammetry (FSCV) to determine how chemogenetic modulation of VTA-DA neurons impacts DA transmission and associated behavioral outputs in awake behaving rats. We further compared these findings with a retrograde intersectional viral approach to selectively modulate VTA-DA projections neurons that innervate the OT. Through immunohistochemical and electrochemical evidence, we demonstrate how modulation of VTA-DA neurons impacts sub-second changes in DA transmission in the OT and compared the effects of global and discrete sub-populations of VTA-DA neuron modulation. In addition, we applied optogenetics to reveal heterogeneous DA regulation (release and clearance) across sub-components of the OT. Taken together, these findings will fill a scientific gap in research regarding a lesser studied brain circuit that may influence the reinforcing effects of drugs greater than neighboring striatal structuresand provide the fundamental framework to understand how local DA circuits are linked to various brain functions as well aspsychiatric and neurodegenerative diseases.