Isabella Farhy-Tselnicker, Ph.D
Molecular Neurobiology Laboratory
Salk Institute for Biological Studies
ABSTRACT
Correct establishment of neuronal synapses during development is crucial for proper brain function. Synaptic deficits have been linked to neurological disorders such as autism and schizophrenia, however, the underlying cellular mechanisms are still poorly understood. Astrocytes, a major type of glial cells, play a key role in synaptogenesis by secreting factors that regulate multiple aspects of synapse formation and function. To find novel treatment avenues, it is critical to identify the mechanisms of astrocyte-neuron communication that regulate synapse formation under normal and pathological conditions.
In this talk I describe my recently published findings, identifying the mechanism by which the astrocyte secreted factor, Glypican 4, induces formation of active synapses. I further describe my ongoing work investigating the regulation of astrocyte derived synapse-promoting genes expression by neuronal and astrocyte activity. My findings provide important insights into the complex interaction between astrocytes and neurons in the developing brain, and establish a framework for future studies of astrocyte roles at the synapse.
Host: Matthew Torres, Ph.D.
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Vollum Institute
Oregon Hearing Research Center
Oregon Health & Science University
The cerebellum is essential for coordinated movement and balance, but despite being a major focus of study for over 100 years, the circuitry and physiology of the cerebellum is incompletely understood. Dr. Balmer’s work focuses on the unipolar brush cell, a recently discovered excitatory interneuron with fascinating synaptic signaling properties. His work elucidates how signals are transformed using unconventional synaptic mechanisms at the unipolar brush cell‘s enormous synapse, which may be a specialization to integrate slowly changing signals. The inputs to these cells were investigated using transgenic, viral and optogenetic approaches, revealing a remarkably specific pattern of innervation from the vestibular system. Dr. Balmer plans to continue studying the role of unipolar brush cells in cerebellar function, as well as in the dorsal cochlear nucleus, a cerebellum-like circuit containing UBCs with important roles in hearing.
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Joshua Plotkin, Ph.D.
Department of Biology
University of Pennsylvania
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Nancy Moran, Ph.D.
Department of Integrative Biology
The University of Texas at Austin
SPEAKER BIO
Moran obtained her bachelor's degree from The University of Texas at Austin and her doctoral degree from the University of Michigan. She is an evolutionary biologist whose research intersects the fields of genetics and genomics, microbiology, entomology, and ecology. Moran’s focus is on genome evolution in host-associated microorganisms, especially bacterial symbionts of insects, and on the consequences of symbiotic associations for biological diversity and ecological relationships. She has authored 200 research papers. Moran was elected as a Member of the National Academy of Science in 2004 and of the American Academy of Arts and Sciences in 2005. She was awarded the International Prize for Biology in 2010. Before coming to The University of Texas at Austin, she was Regent's Professor at the University of Arizona (1986-2010) and the William Fleming Professor of Biology at Yale University (2010-2013).
Host: Marvin Whiteley, Ph.D.
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The Biological Sciences Seminar featuring Jianlong Wang, originally scheduled for March 26, 2020, has been postponed. Please visit biosci.gatech.edu for further updates.
Jianlong Wang, Ph.D.
Columbia Center for Human Development,
Columbia University Irving Medical Center
ABSTRACT
Molecular control of stem cell and developmental potencyresides in a core circuitry of master transcription factors that act in conjunction with epigenetic cofactors for activation and repression of downstream target genes. We have employedboth genomic and proteomic approaches as well as mouse models to study protein-protein interaction and protein-DNAregulatory networks that govern embryonic stem cell (ESC) pluripotency, somatic cell reprogramming, and embryogenesis. Our long-term goal isto understand how cell identity is established, maintained, and altered during mammalian (both mouse and human) developmentunder both normal and pathological conditions. In my talk, I will discussour published and unpublished work dissecting molecular mechanismsunderlying ESCpluripotency, somatic cell reprogramming, and totipotency-to-pluripotency transition during early development.
Host: Yuhong Fan
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The Southeast Center for Mathematics and Biology will host its second annual symposium on the intersection of math and biological systems Feb. 17-18, 2020, at the Marcus Nanotechnology Building at Georgia Tech.
Leading mathematicians and bioscientists will discuss the challenges and opportunities at the math-bio interface while sharing their latest research.
Guest speakers include:
• Guo-Wei Wei (Michigan State University)
• Amina Qutub (University of Texas at San Antonio)
• Kristen Naegle (University of Virginia)
• Konstantin Mischaikow (Rutgers University)
• Alexander Anderson (Moffitt Cancer Center)
• Amy Shaub Maddox (University of North Carolina/Chapel Hill)
• Caroline Uhler (Massachusetts Institute of Technology)
The SCMB is one of four National Science Foundation (NSF) – Simons Research Centers for Mathematics and Complex Biological Systems. It is headquartered at Georgia Tech; other member regional institutions of the SCMB are the Oak Ridge National Laboratory, Tulane University, the University of South Florida, the University of Florida, Clemson University, and Duke University.
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Extracting nectar from flowers that may be dancing in the wind requires precise, millisecond timing between the brain and muscles.
By capturing and analyzing nearly all of the brain signals sent to the wing muscles of hawk moths (Manduca sexta), which feed on such nectar, researchers have shown that precise timing within rapid sequences of neural signal spikes is essential to controlling the flight muscles necessary for the moths to eat.
The research shows that millisecond changes in timing of the action potential spikes, rather than the number or amplitude of the spikes, conveys the majority of information the moths use to coordinate the five muscles in each of their wings. The importance of precise spike timing had been known for certain specific muscles in vertebrates, but the new work shows the general nature of the connection.
“We were able to record simultaneously nearly every signal the moth’s brain uses to control its wings, which gives us an unprecedented and complete window into how the brain is conducting these agile and graceful maneuvers,” said Simon Sponberg, Dunn Family Professor in the School of Physics at the Georgia Institute of Technology. “These muscles are coordinated by subtle shifts in the timing at the millisecond scale rather than by just turning a knob to create more activity. It’s a more subtle story than we might have expected, and there are hints that this may apply more generally.”
The research was reported Dec. 16 in the journal Proceedings of the National Academy of Sciences. The work was supported by the National Science Foundation, the Esther A. & Joseph Klingenstein Fund, and the Simons Foundation.
Researchers Joy Putney, Rachel Conn and Sponberg set out to study how the brain coordinates agile activities such as running or flying that require compensating for perturbations in the air or variations on the ground. While the size of the signals could account for gross control of the behavior, the fine points of choreographing the tasks had to come from elsewhere, they reasoned.
Recording motor control signals in humans and other vertebrates would be a daunting task because so many neurons are used to control so many muscles in even simple behaviors. Fortunately, the researchers knew about the hawk moth, whose flight muscles are each controlled by a single or very few motor neurons. That allowed the researchers to study neural signals by measuring the activity of the corresponding muscles, using tiny wires inserted through the insect’s exoskeleton.
Putney and Conn determined the location of each wing muscle inside the moth exoskeleton, and learned where to create tiny holes for the wires — two for each muscle — that capture the signals. After inserting the wires in the anesthetized moths, the graduate students closed the holes with superglue to hold the wires in place. Connections to a computer system allowed recording and analysis.
“The first time I did the surgery by myself, it took six hours,” said Putney. “Now I can do it in under an hour.”
While connected to the computer, the moths were able to fly on a tether as they viewed a moving 3D-printed plastic flower. To measure the torque forces the moths created as they attempted to track the flower, the wired-up moths were suspended from an accelerometer.
The torque information was then correlated with the spiking signals recorded from each wing muscle.
The importance of the work relates to the completeness of the signal measurement, which brought out the importance of the timing codes to what the moth was doing, Putney said.
“People have recorded lots of muscles together before, but what we have shown is that all of these muscles are using timing codes,” she said. “The way they are using these codes is consistent, regardless of the size of the muscle and how it is attached to the body.”
Indeed, researchers have seen hints about the importance of precision timing in higher animals, and Sponberg believes the hawk moth research should encourage more study into the role of timing. The importance and prevalence of timing across the moth’s motor program also raises questions about how nervous systems in general create precise and coordinated motor commands.
“We think this raises a question that can’t be ignored any longer — whether or not this timing could be the real way that the brain is orchestrating movement,” Sponberg said. “When we look at specific signals in vertebrates, even up to humans, there are hints that this timing could be there.”
The study could also lead to new research on how the brain produces the agile motor control needed for agile movement.
“Now that we know that the motor control is really precise, we can start trying to understand how the brain integrates precise sensory information to do motor control,” Sponberg said. “We want to really understand not only how the brain sets up signals, but also how the biophysics of muscles enables the precise timing that the brain uses.”
This material is based upon work supported by National Science Foundation Graduate Research Fellowships DGE-1650044 and DGE-1444932, an NSF CAREER award (1554790), and a Klingenstein-Simons Fellowship Award in the Neurosciences. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the sponsoring organization.
CITATION: Joy Putney, Rachel Conn, and Simon Sponberg, “Precise timing is ubiquitous, consistent and coordinated across a comprehensive, spike-resolved flight motor program.” (Proceedings of the National Academy of Sciences, 2019.) https://www.pnas.org/content/early/2019/12/11/1907513116
Research News
Georgia Institute of Technology
177 North Avenue
Atlanta, Georgia 30332-0181 USA
Media Relations Contact: John Toon (404-894-6986) (jtoon@gatech.edu)
Writer: John Toon
Silvia Salinas Blemker, Ph.D.
Professor
Biomedical Engineering, Mechanical & Aerospace Engineering, Ophthalmology, and Orthopaedic Surgery
University of Virginia
Abstract
Skeletal muscles are extraordinarily adapted motors that enable us to perform many important functions, from walking to sight to speech. From a basic science perspective, we have a sophisticated understanding of the fundamental biology and mechanics of skeletal muscle. However, how these fundamentals relate to in vivo function is complex and remains poorly understood, which limits the translation of this basic biology understanding to medicine. The goal of the Multi-Scale Muscle Mechanophysiology (“M3”) Lab’s research is to develop and experimentally validate multi-scale computational models of skeletal muscle that allow us to relate structure, biology, and function across a range of muscles. We aim apply these models to answering questions related to the role of complex muscle biology and mechanics in a variety of clinical problems. In this presentation, I will describe these approaches and present some recent examples of how computational models of muscle have led to clinically relevant insights.
Speaker Bio
Silvia Salinas Blemker is a Professor of Biomedical Engineering, with joint appointments in Mechanical & Aerospace Engineering, Ophthalmology, and Orthopaedic Surgery, at the University of Virginia in Charlottesville, VA, USA. She obtained her B.S. and M.S. degrees in Biomedical Engineering from Northwestern University and her Ph.D. degree in Mechanical Engineering from Stanford University. Before joining the faculty at UVa in 2006, Silvia worked as a post-doctoral Research Associate at Stanford University’s National Center for Biomedical Computation. At UVA, she leads the Multi-scale Muscle Mechanophysiology Lab (“M3 Lab”).
The M3 lab group develops advanced multi-scale computational and experimental techniques to study skeletal muscle biomechanics and physiology, and they are currently applying these techniques to variety of areas, including speech disorders, movement disorders, vision impairments, muscle atrophy, aging, and muscular dystrophies. While the work is grounded in biomechanics, it strongly draws from many other fields, including biology, muscle physiology, biomedical computation, continuum mechanics, imaging, and a variety of clinical fields. The M3 lab is enthusiastic to take part in outreach activities, including having active participation of K-12 teachers in the lab and hosting an annual National Biomechanics Day event locally. The M3 lab’s research has been funded by several institutes at the National Institutes of Health (NIAMS, NIBIB, NIA, and NIDCD), NASA, the NSF, the Department of Defense, The Hartwell Foundation, the UVA-Coulter Translational Research Partnership, in addition to industry partnerships. Dr. Blemker has multiple patents pending and recently co-founded Springbok, Inc, a company focused on image-based muscle analytics for a variety of applications from sports medicine to neuromuscular disorders.
Host: Gregory Sawicki
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The ExplOrigins group is hosting the 3rd annual Exploration and Origins Colloquium on January 27th and 28th, in another example of Georgia Tech’s thriving collaboration between the astrobiology and space science communities.The program kicks off with a poster session on Monday, Jan. 27, and continues with plenary lectures, contributed talks, and a networking session on Tuesday, Jan. 28.
The interdisciplinary colloquium will highlight space exploration science, as well as biological, geological, and astronomical origins research in the Georgia Institute of Technology and neighboring universities. The colloquium aims to forge relationships among diverse individuals, encourage collaboration and interdisciplinary understanding, and kick-start fundable projects requiring the skills and expertise of multilab teams.
The colloquium will begin with a poster session on the evening of the 27th where attendees will show off their latest work in an environment conducive to interdisciplinary collaboration. Activities on the 28th include a day-long seminar with twelve contributed talks, and highlighted keynote addresses by: Mariel Borowitz of Georgia Tech’s Sam Nunn School of International Affairs, and Christopher Carr of MIT and Massachusetts General Hospital. This colloquium takes place in the context of a burgeoning astrobiology community at Georgia Tech, with the Institute having recently hosted the Astrobiology Graduate Conference in 2018 and announced the host of Astrobiology Science Conference in 2021.
Register here.
Check here for schedule.
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