Neurosciences Commons^™

A Transcriptomic Taxonomy Of Mouse Brain-Wide Spinal Projecting Neurons, Carla C Winter, Anne Jacobi, Junfeng Su, Leeyup Chung, Cindy T J Van Velthoven, Zizhen Yao, Changkyu Lee, Zicong Zhang, Shuguang Yu, Kun Gao, Geraldine Duque Salazar, Evgenii Kegeles, Yu Zhang, Makenzie C Tomihiro, Yiming Zhang, Zhiyun Yang, Junjie Zhu, Jing Tang, Xuan Song, Ryan J Donahue, Qing Wang, Delissa Mcmillen, Michael Kunst, Ning Wang, Kimberly A Smith, Gabriel E Romero, Michelle M Frank, Alexandra Krol, Riki Kawaguchi, Daniel H Geschwind, Guoping Feng, Lisa V Goodrich, Yuanyuan Liu, Bosiljka Tasic, Hongkui Zeng, Zhigang He

Faculty, Staff and Student Publications

The brain controls nearly all bodily functions via spinal projecting neurons (SPNs) that carry command signals from the brain to the spinal cord. However, a comprehensive molecular characterization of brain-wide SPNs is still lacking. Here we transcriptionally profiled a total of 65,002 SPNs, identified 76 region-specific SPN types, and mapped these types into a companion atlas of the whole mouse brain1. This taxonomy reveals a three-component organization of SPNs: (1) molecularly homogeneous excitatory SPNs from the cortex, red nucleus and cerebellum with somatotopic spinal terminations suitable for point-to-point communication; (2) heterogeneous populations in the reticular formation with broad …

Single-Cell Analysis Of Chromatin Accessibility In The Adult Mouse Brain, Songpeng Zu, Yang Eric Li, Kangli Wang, Ethan J Armand, Sainath Mamde, Maria Luisa Amaral, Yuelai Wang, Andre Chu, Yang Xie, Michael Miller, Jie Xu, Zhaoning Wang, Kai Zhang, Bojing Jia, Xiaomeng Hou, Lin Lin, Qian Yang, Seoyeon Lee, Bin Li, Samantha Kuan, Hanqing Liu, Jingtian Zhou, Antonio Pinto-Duarte, Jacinta Lucero, Julia Osteen, Michael Nunn, Kimberly A Smith, Bosiljka Tasic, Zizhen Yao, Hongkui Zeng, Zihan Wang, Jingbo Shang, M Margarita Behrens, Joseph R Ecker, Allen Wang, Sebastian Preissl, Bing Ren

Faculty, Staff and Student Publications

Recent advances in single-cell technologies have led to the discovery of thousands of brain cell types; however, our understanding of the gene regulatory programs in these cell types is far from complete1-4. Here we report a comprehensive atlas of candidate cis-regulatory DNA elements (cCREs) in the adult mouse brain, generated by analysing chromatin accessibility in 2.3 million individual brain cells from 117 anatomical dissections. The atlas includes approximately 1 million cCREs and their chromatin accessibility across 1,482 distinct brain cell populations, adding over 446,000 cCREs to the most recent such annotation in the mouse genome. The mouse brain cCREs are …

Voltage- And Calcium-Gated Membrane Currents Tune The Plateau Potential Properties Of Multiple Neuron Types, Curtis L Neveu, Paul Smolen, Douglas A Baxter, John H Byrne

Faculty, Staff and Student Publications

Many neurons exhibit regular firing that is limited to the duration and intensity of depolarizing stimuli. However, some neurons exhibit all-or-nothing plateau potentials that, once elicited, can lead to prolonged activity that is independent of stimulus intensity or duration. To better understand this diversity of information processing, we compared the voltage-gated and Ca2+-gated currents of three identified neurons from hermaphroditic Aplysia californica Two of these neurons, B51 and B64, generated plateau potentials and a third neuron, B8, exhibited regular firing and was incapable of generating a plateau potential. With the exception of the Ca2+-gated potassium current (I KCa), all …

Widefield Imaging Of Rapid Pan-Cortical Voltage Dynamics With An Indicator Evolved For One-Photon Microscopy, Xiaoyu Lu, Yunmiao Wang, Zhuohe Liu, Yueyang Gou, Dieter Jaeger, François St-Pierre

Faculty, Staff and Students Publications

Widefield imaging with genetically encoded voltage indicators (GEVIs) is a promising approach for understanding the role of large cortical networks in the neural coding of behavior. However, the limited performance of current GEVIs restricts their deployment for single-trial imaging of rapid neuronal voltage dynamics. Here, we developed a high-throughput platform to screen for GEVIs that combine fast kinetics with high brightness, sensitivity, and photostability under widefield one-photon illumination. Rounds of directed evolution produced JEDI-1P, a green-emitting fluorescent indicator with enhanced performance across all metrics. Next, we optimized a neonatal intracerebroventricular delivery method to achieve cost-effective and wide-spread JEDI-1P expression in …

Excitatory Neuron-Specific Suppression Of The Integrated Stress Response Contributes To Autism-Related Phenotypes In Fragile X Syndrome, Mehdi Hooshmandi, Vijendra Sharma, Carolina Thörn Perez, Rapita Sood, Konstanze Krimbacher, Calvin Wong, Kevin C Lister, Alba Ureña Guzmán, Trevor D Bartley, Cecilia Rocha, Gilles Maussion, Emma Nadler, Patricia Margarita Roque, Ilse Gantois, Jelena Popic, Maxime Lévesque, Randal J Kaufman, Massimo Avoli, Elisenda Sanz, Karim Nader, Randi Jenssen Hagerman, Thomas M Durcan, Mauro Costa-Mattioli, Masha Prager-Khoutorsky, Jean-Claude Lacaille, Veronica Martinez-Cerdeno, Jay R Gibson, Kimberly M Huber, Nahum Sonenberg, Christos G Gkogkas, Arkady Khoutorsky

Faculty, Staff and Students Publications

Dysregulation of protein synthesis is one of the key mechanisms underlying autism spectrum disorder (ASD). However, the role of a major pathway controlling protein synthesis, the integrated stress response (ISR), in ASD remains poorly understood. Here, we demonstrate that the main arm of the ISR, eIF2α phosphorylation (p-eIF2α), is suppressed in excitatory but not inhibitory neurons in a mouse model of fragile X syndrome (FXS; Fmr1−/y). We further show that the decrease in p-eIF2α is mediated via activation of the mTORC1. Genetic reduction of p-eIF2α only in excitatory neurons is sufficient to increase general protein synthesis and cause autism-like …

Pirh2-Dependent Dna Damage In Neurons Induced By The G-Quadruplex Ligand Pyridostatin, Rocio Diaz Escarcega, Abhijeet A Patil, Jose F Moruno-Manchon, Akihiko Urayama, Sean P Marrelli, Nayun Kim, David Monchaud, Louise D Mccullough, Andrey S Tsvetkov

Faculty, Staff and Student Publications

Noncanonical base pairing between four guanines (G) within single-stranded G-rich sequences leads to formation of а G-quartet. Self-stacking of G-quartets results in a columnar four-stranded DNA structure known as the G-quadruplex (G4 or G4-DNA). In cancer cells, G4-DNA regulates multiple DNA-dependent processes, including transcription, replication, and telomere function. How G4s function in neurons is poorly understood. Here, we performed a genome-wide gene expression analysis (RNA-Seq) to identify genes modulated by a G4-DNA ligand, pyridostatin (PDS), in primary cultured neurons. PDS promotes stabilization of G4 structures, thus allowing us to define genes directly or indirectly responsive to G4 regulation. We found …

The Microtubule Quartet Protein Snap1 In Trypanosoma Brucei Facilitates Flagellum And Cell Division Plane Positioning By Promoting Basal Body Segregation, Martin Carbo-Tano, Mathilde Lapoix, Xinyu Jia, Olivier Thouvenin, Marco Pascucci, François Auclair, Feng B Quan, Shahad Albadri, Vernie Aguda, Younes Farouj, Elizabeth M C Hillman, Ruben Portugues, Filippo Del Bene, Tod R Thiele, Réjean Dubuc, Claire Wyart

Faculty, Staff and Student Publications

The mesencephalic locomotor region (MLR) is a brain stem area whose stimulation triggers graded forward locomotion. How MLR neurons recruit downstream vsx2+ (V2a) reticulospinal neurons (RSNs) is poorly understood. Here, to overcome this challenge, we uncovered the locus of MLR in transparent larval zebrafish and show that the MLR locus is distinct from the nucleus of the medial longitudinal fasciculus. MLR stimulations reliably elicit forward locomotion of controlled duration and frequency. MLR neurons recruit V2a RSNs via projections onto somata in pontine and retropontine areas, and onto dendrites in the medulla. High-speed volumetric imaging of neuronal activity reveals that …

A Cross-Species Proteomic Map Reveals Neoteny Of Human Synapse Development, Li Wang, Kaifang Pang, Li Zhou, Arantxa Cebrián-Silla, Susana González-Granero, Shaohui Wang, Qiuli Bi, Matthew L White, Brandon Ho, Jiani Li, Tao Li, Yonatan Perez, Eric J Huang, Ethan A Winkler, Mercedes F Paredes, Rothem Kovner, Nenad Sestan, Alex A Pollen, Pengyuan Liu, Jingjing Li, Xianhua Piao, José Manuel García-Verdugo, Arturo Alvarez-Buylla, Zhandong Liu, Arnold R Kriegstein

Faculty, Staff and Students Publications

The molecular mechanisms and evolutionary changes accompanying synapse development are still poorly understood1,2. Here we generate a cross-species proteomic map of synapse development in the human, macaque and mouse neocortex. By tracking the changes of more than 1,000 postsynaptic density (PSD) proteins from midgestation to young adulthood, we find that PSD maturation in humans separates into three major phases that are dominated by distinct pathways. Cross-species comparisons reveal that human PSDs mature about two to three times slower than those of other species and contain higher levels of Rho guanine nucleotide exchange factors (RhoGEFs) in the …

Convergent Escape Behaviour From Distinct Visual Processing Of Impending Collision In Fish And Grasshoppers, Richard B Dewell, Terri Carroll-Mikhail, Margaret R Eisenbrandt, Alexander F Mendoza, Bidisha Halder, Thomas Preuss, Fabrizio Gabbiani

Faculty, Staff and Students Publications

In animal species ranging from invertebrate to mammals, visually guided escape behaviours have been studied using looming stimuli, the two-dimensional expanding projection on a screen of an object approaching on a collision course at constant speed. The peak firing rate or membrane potential of neurons responding to looming stimuli often tracks a fixed threshold angular size of the approaching stimulus that contributes to the triggering of escape behaviours. To study whether this result holds more generally, we designed stimuli that simulate acceleration or deceleration over the course of object approach on a collision course. Under these conditions, we found that …

Structure, Function, And Molecular Landscapes Of The Aging Retina, Jeffrey D Zhu, Sharma Pooja Tarachand, Qudrat Abdulwahab, Melanie A Samuel

Faculty, Staff and Students Publications

Because the central nervous system is largely nonrenewing, neurons and their synapses must be maintained over the lifetime of an individual to ensure circuit function. Age is a dominant risk factor for neural diseases, and declines in nervous system function are a common feature of aging even in the absence of disease. These alterations extend to the visual system and, in particular, to the retina. The retina is a site of clinically relevant age-related alterations but has also proven to be a uniquely approachable system for discovering principles that govern neural aging because it is well mapped, contains diverse neuron …

Piezo2 In Somatosensory Neurons Controls Gastrointestinal Transit, M Rocio Servin-Vences, Ruby M Lam, Alize Koolen, Yu Wang, Dimah N Saade, Meaghan Loud, Halil Kacmaz, Suzanne Frausto, Yunxiao Zhang, Arthur Beyder, Kara L Marshall, Carsten G Bönnemann, Alexander T Chesler, Ardem Patapoutian

Duncan NRI Faculty and Staff Publications

The gastrointestinal tract is in a state of constant motion. These movements are tightly regulated by the presence of food and help digestion by mechanically breaking down and propelling gut content. Mechanical sensing in the gut is thought to be essential for regulating motility; however, the identity of the neuronal populations, the molecules involved, and the functional consequences of this sensation are unknown. Here, we show that humans lacking PIEZO2 exhibit impaired bowel sensation and motility. Piezo2 in mouse dorsal root, but not nodose ganglia is required to sense gut content, and this activity slows down food transit rates in …

Injury Induced Neuroplasticity And Cell Specific Targeting Of The Lumbar Enlargement For Gene Therapy., Brandon Lee Brown

Electronic Theses and Dissertations

This dissertation is an examination of spinal cord injury induced neuroplasticity and tests whether noninvasive gene therapy can successfully target neurons in the lumbar spinal cord. It begins with an overview of neural control of locomotion and a brief summary of therapeutics that are used and/or in development for treating spinal anatomically characterize s subset of neurons in the spinal cord, long ascending propriospinal neurons, that are involved in interlimb coordination. Characterization of these neurons allows for subsequent evaluation of their potential involvement in injury induced neuroplasticity. This dissertation is divided into five chapters, covering spinal cord injury and therapeutics. …

Combining Voltage-Sensitive Dye, Carbon Fiber Array, And Extracellular Nerve Electrodes Using A 3-D Printed Recording Chamber And Manipulators, Curtis L Neveu, Yu Huan, Yuto Momohara, Paras R Patel, Hillel J Chiel, Cynthia A Chestek, John H Byrne

Faculty, Staff and Student Publications

BACKGROUND: The analyses of neuronal circuits require high-throughput technologies for stimulating and recording many neurons simultaneously with single-neuron precision. Voltage-sensitive dyes (VSDs) have enabled the monitoring of membrane potentials of many (10-100 s) neurons simultaneously. Carbon fiber electrode (CFE) arrays allow for stimulation and recording of many neurons simultaneously, including intracellularly.

NEW METHOD: Combining CFE with VSD leverages the advantages of both technologies, allowing for stimulation of single neurons while recording the activity of the entire network. 3-D printing technology was used to develop a chamber to simultaneously perform VSD imaging, CFE array recording, and extracellular recording from individual glass …

Βii-Spectrin Is Required For Synaptic Positioning During Retinal Development, Debalina Goswami-Sewell, Caitlin Bagnetto, Cesiah C Gomez, Joseph T Anderson, Akash Maheshwari, Elizabeth Zuniga-Sanchez

Faculty, Staff and Students Publications

Neural circuit assembly is a multistep process where synaptic partners are often born at distinct developmental stages, and yet they must find each other and form precise synaptic connections with one another. This developmental process often relies on late-born neurons extending their processes to the appropriate layer to find and make synaptic connections to their early-born targets. The molecular mechanism responsible for the integration of late-born neurons into an emerging neural circuit remains unclear. Here, we uncovered a new role for the cytoskeletal protein βII-spectrin in properly positioning presynaptic and postsynaptic neurons to the developing synaptic layer. Loss of βII-spectrin …

Anoctamin 4 Channel Currents Activate Glucose-Inhibited Neurons In The Mouse Ventromedial Hypothalamus During Hypoglycemia, Longlong Tu, Jonathan C Bean, Yang He, Hailan Liu, Meng Yu, Hesong Liu, Nan Zhang, Na Yin, Junying Han, Nikolas A Scarcelli, Kristine M Conde, Mengjie Wang, Yongxiang Li, Bing Feng, Peiyu Gao, Zhao-Lin Cai, Makoto Fukuda, Mingshan Xue, Qingchun Tong, Yongjie Yang, Lan Liao, Jianming Xu, Chunmei Wang, Yanlin He, Yong Xu

Faculty, Staff and Student Publications

Glucose is the basic fuel essential for maintenance of viability and functionality of all cells. However, some neurons - namely, glucose-inhibited (GI) neurons - paradoxically increase their firing activity in low-glucose conditions and decrease that activity in high-glucose conditions. The ionic mechanisms mediating electric responses of GI neurons to glucose fluctuations remain unclear. Here, we showed that currents mediated by the anoctamin 4 (Ano4) channel are only detected in GI neurons in the ventromedial hypothalamic nucleus (VMH) and are functionally required for their activation in response to low glucose. Genetic disruption of the Ano4 gene in VMH neurons reduced blood …

Cortex-Wide Neural Dynamics Predict Behavioral States And Provide A Neural Basis For Resting-State Dynamic Functional Connectivity, Somayeh Shahsavarani, David N Thibodeaux, Weihao Xu, Sharon H Kim, Fatema Lodgher, Chinwendu Nwokeabia, Morgan Cambareri, Alexis J Yagielski, Hanzhi T Zhao, Daniel A Handwerker, Javier Gonzalez-Castillo, Peter A Bandettini, Elizabeth M C Hillman

Faculty, Staff and Student Publications

Although resting-state functional magnetic resonance imaging (fMRI) studies have observed dynamically changing brain-wide networks of correlated activity, fMRI's dependence on hemodynamic signals makes results challenging to interpret. Meanwhile, emerging techniques for real-time recording of large populations of neurons have revealed compelling fluctuations in neuronal activity across the brain that are obscured by traditional trial averaging. To reconcile these observations, we use wide-field optical mapping to simultaneously record pan-cortical neuronal and hemodynamic activity in awake, spontaneously behaving mice. Some components of observed neuronal activity clearly represent sensory and motor function. However, particularly during quiet rest, strongly fluctuating patterns of activity across …

Target Cell-Specific Synaptic Dynamics Of Excitatory To Inhibitory Neuron Connections In Supragranular Layers Of Human Neocortex, Mean-Hwan Kim, Cristina Radaelli, Elliot R Thomsen, Deja Monet, Thomas Chartrand, Nikolas L Jorstad, Joseph T Mahoney, Michael J Taormina, Brian Long, Katherine Baker, Trygve E Bakken, Luke Campagnola, Tamara Casper, Michael Clark, Nick Dee, Florence D'Orazi, Clare Gamlin, Brian E Kalmbach, Sara Kebede, Brian R Lee, Lindsay Ng, Jessica Trinh, Charles Cobbs, Ryder P Gwinn, C Dirk Keene, Andrew L Ko, Jeffrey G Ojemann, Daniel L Silbergeld, Staci A Sorensen, Jim Berg, Kimberly A Smith, Philip R Nicovich, Tim Jarsky, Hongkui Zeng, Jonathan T Ting, Boaz P Levi, Ed Lein

Faculty, Staff and Student Publications

Rodent studies have demonstrated that synaptic dynamics from excitatory to inhibitory neuron types are often dependent on the target cell type. However, these target cell-specific properties have not been well investigated in human cortex, where there are major technical challenges in reliably obtaining healthy tissue, conducting multiple patch-clamp recordings on inhibitory cell types, and identifying those cell types. Here, we take advantage of newly developed methods for human neurosurgical tissue analysis with multiple patch-clamp recordings, post-hoc fluorescent in situ hybridization (FISH), machine learning-based cell type classification and prospective GABAergic AAV-based labeling to investigate synaptic properties between pyramidal neurons and PVALB- …

Glutamatergic Cerebellar Neurons Differentially Contribute To The Acquisition Of Motor And Social Behaviors, Meike E Van Der Heijden, Alejandro G Rey Hipolito, Linda H Kim, Dominic J Kizek, Ross M Perez, Tao Lin, Roy V Sillitoe

Duncan NRI Faculty and Staff Publications

Insults to the developing cerebellum can cause motor, language, and social deficits. Here, we investigate whether developmental insults to different cerebellar neurons constrain the ability to acquire cerebellar-dependent behaviors. We perturb cerebellar cortical or nuclei neuron function by eliminating glutamatergic neurotransmission during development, and then we measure motor and social behaviors in early postnatal and adult mice. Altering cortical and nuclei neurons impacts postnatal motor control and social vocalizations. Normalizing neurotransmission in cortical neurons but not nuclei neurons restores social behaviors while the motor deficits remain impaired in adults. In contrast, manipulating only a subset of nuclei neurons leaves social …

Functional Neuronal Circuits Promote Disease Progression In Cancer, Anthony C Restaino, Austin Walz, Samuel J Vermeer, Jeffrey Barr, Attila Kovács, Robin R Fettig, Daniel W Vermeer, Hunter Reavis, Caitlin S Williamson, Christopher T Lucido, Tuany Eichwald, Dalia K Omran, Euihye Jung, Lauren E Schwartz, Maria Bell, Desirae M Muirhead, Jody E Hooper, William C Spanos, Ronny Drapkin, Sebastien Talbot, Paola D Vermeer

Faculty, Staff and Student Publications

The molecular and functional contributions of intratumoral nerves to disease remain largely unknown. We localized synaptic markers within tumors suggesting that these nerves form functional connections. Consistent with this, electrophysiological analysis shows that malignancies harbor significantly higher electrical activity than benign disease or normal tissues. We also demonstrate pharmacologic silencing of tumoral electrical activity. Tumors implanted in transgenic animals lacking nociceptor neurons show reduced electrical activity. These data suggest that intratumoral nerves remain functional at the tumor bed. Immunohistochemical staining demonstrates the presence of the neuropeptide, Substance P (SP), within the tumor space. We show that tumor cells express the …

Inhibitory Input Directs Astrocyte Morphogenesis Through Glial Gababr, Yi-Ting Cheng, Estefania Luna-Figueroa, Junsung Woo, Hsiao-Chi Chen, Zhung-Fu Lee, Akdes Serin Harmanci, Benjamin Deneen

Faculty, Staff and Students Publications

Communication between neurons and glia plays an important role in establishing and maintaining higher order brain function1. Astrocytes are endowed with complex morphologies which places their peripheral processes in close proximity to neuronal synapses and directly contributes to their regulation of brain circuits2–4. Recent studies have shown that excitatory neuronal activity promotes oligodendrocyte differentiation5–7; whether inhibitory neurotransmission regulates astrocyte morphogenesis during development is unknown. Here we show that inhibitory neuron activity is necessary and sufficient for astrocyte morphogenesis. We found that input from inhibitory neurons functions through astrocytic GABABR and …

Social Deprivation Induces Astrocytic Trpa1-Gaba Suppression Of Hippocampal Circuits, Yi-Ting Cheng, Junsung Woo, Estefania Luna-Figueroa, Ehson Maleki, Akdes Serin Harmanci, Benjamin Deneen

Faculty, Staff and Students Publications

Social experience is essential for the development and maintenance of higher order brain function. Social deprivation results in a host of cognitive deficits and cellular studies have largely focused on associated neuronal dysregulation; how astrocyte function is impacted by social deprivation is unknown. Here we show that hippocampal astrocytes from juvenile mice subjected to social isolation exhibit increased Ca2+ activity and global changes in gene expression. We found that the Ca2+ channel TRPA1 is upregulated in astrocytes after social deprivation and astrocyte-specific deletion of TRPA1 reverses the physiological and cognitive deficits associated with social deprivation. Mechanistically, TRPA1 inhibition of hippocampal …

Cancer Neuroscience: State Of The Field, Emerging Directions, Frank Winkler, Humsa S Venkatesh, Moran Amit, Tracy Batchelor, Ihsan Ekin Demir, Benjamin Deneen, David H Gutmann, Shawn Hervey-Jumper, Thomas Kuner, Donald Mabbott, Michael Platten, Asya Rolls, Erica K Sloan, Timothy C Wang, Wolfgang Wick, Varun Venkataramani, Michelle Monje

Faculty, Staff and Student Publications

The nervous system governs both ontogeny and oncology. Regulating organogenesis during development, maintaining homeostasis, and promoting plasticity throughout life, the nervous system plays parallel roles in the regulation of cancers. Foundational discoveries have elucidated direct paracrine and electrochemical communication between neurons and cancer cells, as well as indirect interactions through neural effects on the immune system and stromal cells in the tumor microenvironment in a wide range of malignancies. Nervous system-cancer interactions can regulate oncogenesis, growth, invasion and metastatic spread, treatment resistance, stimulation of tumor-promoting inflammation, and impairment of anti-cancer immunity. Progress in cancer neuroscience may create an important new …

Identification Of A Gabaergic Neural Circuit Governing Leptin Signaling Deficiency-Induced Obesity, Yong Han, Yang He, Lauren Harris, Yong Xu, Qi Wu

Faculty, Staff and Students Publications

The hormone leptin is known to robustly suppress food intake by acting upon the leptin receptor (LepR) signaling system residing within the agouti-related protein (AgRP) neurons of the hypothalamus. However, clinical studies indicate that leptin is undesirable as a therapeutic regiment for obesity, which is at least partly attributed to the poorly understood complex secondary structure and key signaling mechanism of the leptin-responsive neural circuit. Here, we show that the LepR-expressing portal neurons send GABAergic projections to a cohort of α3-GABAA receptor expressing neurons within the dorsomedial hypothalamic nucleus (DMH) for the control of leptin-mediated obesity phenotype. We identified the …

Approaching Object Acceleration Differentially Affects The Predictions Of Neuronal Collision Avoidance Models, Fabrizio Gabbiani, Thomas Preuss, Richard B Dewell

Faculty, Staff and Students Publications

The processing of visual information for collision avoidance has been investigated at the biophysical level in several model systems. In grasshoppers, the (so-called) [Formula: see text] model captures reasonably well the visual processing performed by an identified neuron called the lobular giant movement detector as it tracks approaching objects. Similar phenomenological models have been used to describe either the firing rate or the membrane potential of neurons responsible for visually guided collision avoidance in other animals. Specifically, in goldfish, the [Formula: see text] model has been proposed to describe the Mauthner cell, an identified neuron involved in startle escape responses. …

Glia-Neuron Coupling Via A Bipartite Sialylation Pathway Promotes Neural Transmission And Stress Tolerance Iglia-Neuron Coupling Via A Bipartite Sialylation Pathway Promotes Neural Transmission And Stress Tolerance In Drosophila, Hilary Scott, Boris Novikov, Berrak Ugur, Brooke Allen, Ilya Mertsalov, Pedro Monagas-Valentin, Melissa Koff, Sarah Baas Robinson, Kazuhiro Aoki, Raisa Veizaj, Dirk J Lefeber, Michael Tiemeyer, Hugo Bellen, Vladislav Panin

Duncan NRI Faculty and Staff Publications

Modification by sialylated glycans can affect protein functions, underlying mechanisms that control animal development and physiology. Sialylation relies on a dedicated pathway involving evolutionarily conserved enzymes, including CMP-sialic acid synthetase (CSAS) and sialyltransferase (SiaT) that mediate the activation of sialic acid and its transfer onto glycan termini, respectively. In Drosophila, CSAS and DSiaT genes function in the nervous system, affecting neural transmission and excitability. We found that these genes function in different cells: the function of CSAS is restricted to glia, while DSiaT functions in neurons. This partition of the sialylation pathway allows for regulation of neural functions via …

Intravital Imaging Of Cellular Response Due To Traumatic Brain Injury Using Confocal Microscopy, Enoch G. Kim, Jeffrey Horbatiuk, Carolyn Harris

Medical Student Research Symposium

Introduction: Cellular reaction to traumatic brain injury is complex and involves considerable interactions between cells and reactivity to foreign bodies. Our objective was to assess neurons, microglia, astrocytes, and intracellular Ca²⁺ signaling by creating a novel confocal microscopy technique involving an air immersed lens that does not sacrifice resolution and limits signal attenuation. This study aimed to create a consistent dynamic methodology to observe the cortical cellular response using real-time intravital imaging as trauma is being induced.

Methods: Once surgical plane was achieved, rodent cortices were exposed via craniotomy and blunt insertion with a silicone shunt catheter into the …

Asprosin Promotes Feeding Through Sk Channel-Dependent Activation Of Agrp Neurons, Bing Feng, Hesong Liu, Ila Mishra, Clemens Duerrschmid, Peiyu Gao, Pingwen Xu, Chunmei Wang, Yanlin He

Faculty, Staff and Students Publications

Asprosin, a recently identified adipokine, activates agouti-related peptide (AgRP) neurons in the arcuate nucleus of the hypothalamus (ARH) via binding to protein tyrosine phosphatase receptor δ (Ptprd) to increase food intake. However, the intracellular mechanisms responsible for asprosin/Ptprd-mediated activation of AgRPARH neurons remain unknown. Here, we demonstrate that the small-conductance calcium-activated potassium (SK) channel is required for the stimulatory effects of asprosin/Ptprd on AgRPARH neurons. Specifically, we found that deficiency or elevation of circulating asprosin increased or decreased the SK current in AgRPARH neurons, respectively. AgRPARH-specific deletion of SK3 (an SK channel subtype highly expressed in AgRPARH neurons) blocked asprosin-induced …

Mutations In The Transcriptional Regulator Mecp2 Severely Impact Key Cellular And Molecular Signatures Of Human Astrocytes During Maturation, Jialin Sun, Sivan Osenberg, Austin Irwin, Li-Hua Ma, Nigel Lee, Yangfei Xiang, Feng Li, Ying-Wooi Wan, In-Hyun Park, Mirjana Maletic-Savatic, Nurit Ballas

Faculty, Staff and Students Publications

Mutations in the MECP2 gene underlie a spectrum of neurodevelopmental disorders, most commonly Rett syndrome (RTT). We ask whether MECP2 mutations interfere with human astrocyte developmental maturation, thereby affecting their ability to support neurons. Using human-based models, we show that RTT-causing MECP2 mutations greatly impact the key role of astrocytes in regulating overall brain bioenergetics and that these metabolic aberrations are likely mediated by dysfunctional mitochondria. During post-natal maturation, astrocytes rely on neurons to induce their complex stellate morphology and transcriptional changes. While MECP2 mutations cause cell-intrinsic aberrations in the astrocyte transcriptional landscape, surprisingly, they do not affect the neuron-induced …

Mass Spectrometry Imaging As An Emerging Tool For Studying Metabolism In Human Brain Organoids, Gerarda Cappuccio, Saleh M Khalil, Sivan Osenberg, Feng Li, Mirjana Maletic-Savatic

Faculty, Staff and Students Publications

Human brain organoids are emerging models to study human brain development and pathology as they recapitulate the development and characteristics of major neural cell types, and enable manipulation through an in vitro system. Over the past decade, with the advent of spatial technologies, mass spectrometry imaging (MSI) has become a prominent tool for metabolic microscopy, providing label-free, non-targeted molecular and spatial distribution information of the metabolites within tissue, including lipids. This technology has never been used for studies of brain organoids and here, we set out to develop a standardized protocol for preparation and mass spectrometry imaging of human brain …

Editorial: Molecular Mechanisms In Ocular Development And Disease, Rajalekshmy Shyam, Daisy Y Shu, Elizabeth Zuniga-Sanchez, Deepika Vasudevan

Faculty, Staff and Students Publications

No abstract provided.