Seminar Series

All seminars are held in NHB 1.720 unless noted otherwise.

To subscribe to our Seminars mailing list, please visit https://utlists.utexas.edu/sympa/info/neu-seminars and click on "Subscribe" in the left column.

For any inquiries, you may contact Neuro.Seminar.Series@austin.utexas.edu.

Roger Nicoll, MD

University of California, San Francisco

Department of Cellular and Molecular Pharmacology

A molecular machine for memory

Monday, September 11, 2023 3:00 PM Hosted by Amy Lee

Roger Nicoll at UCSF ↗

Abstract

CaMKII and long-term potentiation (LTP) were discovered within a decade of each other and have been inextricably intertwined ever since. Francis Crick proposed that a memory molecule should possess two properties. First, it should be a multimeric protein with identical subunits that can phosphorylate each other. Second, to address how memories outlast molecular turnover he proposed that naïve unphosphorylated subunits could exchange into the phosphorylated multimer and become phosphorylated. Within two years CaMKII was shown to satisfy the first property. In my talk I will show that the autophosphorylation of CaMKII, indeed, maintains LTP (memory) by the synaptic capture of AMPA receptors and that this memory survives the protein turnover of CaMKII.

Claudia Lucchinetti, MD

Dean, Dell Medical School, The University of Texas at Austin

Department of Neurology

Multimodal Imaging of Multiple Sclerosis Pathlogy: From Structure to Function

Monday, September 18, 2023 3:00 PM Hosted by Dr. Bob Messing

Lucchinetti, Dell Med Dean ↗

Abstract

Background: Multiple sclerosis (MS) is a chronic inflammatory demyelinating disorder of the central nervous system, pathologically characterized by focal demyelination, inflammation, scar formation, and variable axonal destruction. Lesion evolution in MS is highly dynamic and not well understood likely contributing to the inability to halt or reverse disease progression. The presence of mitochondrial dysfunction, oxidative injury, and metabolic changes in MS raises the possibility of influencing metal equilibrium and the behavior of vital macromolecules, such as lipids, proteins, nucleic acids, and carbohydrates. This study aims to characterize MS lesion features through a multidisciplinary approach to gain a comprehensive understanding of the disease.

Methods: Human formalin-fixed biopsy and autopsy tissue of MS patients were investigated with immunohistochemistry for the classification of demyelinating pathology. Synchrotron-based X-ray fluorescence (XRF) microscopy was used to map transition metals with high precision, revealing distinct metal distributions among different immunopatterns of MS lesions. Fourier-transformed infrared (FTIR) spectroscopy was employed to investigate alterations in biomolecules within lesions, providing insights into oxidative stress-induced changes in lipids, proteins, and other constituents. We utilized laser capture microdissection and proteomics to interrogate mechanisms that may be driving lesion progression.

Results: XRF microscopy revealed heterogeneous iron accumulation across MS immunopatterns, suggesting diverse disease mechanisms. Early active lesions of immunopattern II display greater iron accumulation compared to immunopattern III, potentially due to variations in macrophage polarization and origin. This study also uncovers the interplay between iron and zinc under hypoxic conditions, linking metal imbalances to HIF-1α expression and astrocyte demise. Iron's role in remyelination is explored, highlighting its potential facilitation through astrocyte-driven iron efflux. However, in an inflammatory context, uncontrolled iron release may exacerbate oxidative damage and neurodegeneration. FTIR spectroscopy revealed MS lesion-specific alterations in lipids and proteins indicative of oxidative damage. These changes include shortened lipid chains, increased unsaturation, and shifts in protein secondary structures. Additional FTIR peaks corresponding to glycogen suggest altered energy metabolism in chronic MS lesions, potentially involving anaerobic pathways. Proteomics analysis of inactive lesions and periplaque white matter identified differentially expressed proteins that may be important in myelination, metabolic function, focal adhesions, and cellular homeostasis.

Conclusion: Overall, these results suggest that the integration of different imaging platforms and region-specific proteome changes can enhance our understanding of the evolution of lesion progression in MS. Iron's dual role as a cofactor and source of oxidative stress underscores its complex contribution to MS pathogenesis. These findings unveil distinct metal distributions among MS immunopatterns, lesion-specific lipid, protein, and energy metabolism alterations, revealing complexities beyond routine histopathology. This comprehensive framework offers valuable insights into MS mechanisms, potentially leading to biomarker discoveries and novel therapeutic interventions.

Erik Jorgensen, PhD

University of Utah, Department of Biomedical Engineering

Howard Hughes Medical Institute

Synaptic Transmission in Time (ms) and in Space (nm)

Monday, September 25, 2023 3:00 PM Hosted by Dr. Jon Pierce

Erik Jorgensen ↗

Abstract

Neurons couple to one another at synapses and can track action potentials firing at 100-1000 times a second. How do synapses fire at these rates with fidelity and at the same time remain robust for high frequency stimulation. To explore membrane dynamics at synapses we are pursuing a forward genetic strategy using the nematode C. elegans and validate our findings in cultured rodent neurons using superresolution fluorescence microscopy, time-resolved electron microscopy and electrophysiology.

Exocytosis. Synaptic vesicles dock and are poised to fuse with the plasma membrane. Fusion is initiated by calcium influx into the synapse. The speed of fusion is maintained by coupling synaptic vesicles to calcium channels at docking sites, so that calcium reaches the fusion site within microseconds.

Endocytosis. Synaptic vesicle proteins and membrane must be recovered after fusing to the synaptic membrane. To capture images of endocytosis in a living organism, we combined optogenetics, high-pressure freezing and electron microscopy. We observed that in mouse neurons membrane is recycled within 50 to 300 milliseconds after stimulation. This novel form of membrane recovery is called ultrafast endocytosis, and it allows the synapses to recover synaptic vesicle components to maintain neurotransmission.

Krešimir Josić, PhD

University of Houston

Department of Mathematics

Plasticity, balance and the structure of neuronal networks

Monday, October 9, 2023 3:00 PM Hosted by Thibaud Taillefumier

Kresimir Josic at UH ↗

Abstract

I will first describe how to extend the theory of balanced networks to account for synaptic plasticity. This theory can be used to show when a plastic network will maintain balance, and when it will be driven into an unbalanced state. I will next discuss how this approach provides evidence for a novel form of rapid compensatory inhibitory plasticity. Experimental evidence for such plasticity comes from optogenetic activation of excitatory neurons in primate visual cortex (area V1) which induces a population-wide dynamic reduction in the strength of neuronal interactions over the timescale of minutes during the awake state, but not during rest. I will shift gears in the final part of the talk, and discuss how community detection algorithms can help uncover the large scale organization of neuronal networks using connectome data.

Kristina Nielsen, PhD

The Johns Hopkins University

Zanvyl Krieger Mind/Brain Institute

Representation of 3D and 2D shape in visual area V4

Monday, October 16, 2023 3:00 PM Hosted by Dr. Nicholas Priebe

Nielsen Lab ↗

Abstract

Shape coding in mid-level visual area V4 has generally been discussed in terms of processing of flat or 2D shapes. Yet, the world around us is 3-dimensional and filled with solid, volumetric objects. In this talk, I will discuss our recent findings that 3D, volumetric shape is robustly represented in V4, showing that this complex tuning property emerges at a much earlier processing stage than commonly assumed. In addition to tuning for 3D shape parameters, we also used 2-photon imaging to demonstrate that preference for 3D or 2D shape is reflected in the micro-organization of V4, with neurons clustering according to their preference for either type of shape. This further highlights the importance of 3D shape encoding in V4, and is an important addition to early shape-processing models that so far have largely focused on 2D pattern processing..

Shantanu Jadhav, PhD

Brandeis University

Department of Psychology

Neural coordination mechanisms for memory-guided behavior

Monday, October 30, 2023 3:00 PM Hosted by Dr. Laura Colgin

Jadhav Lab ↗

Abstract

Our brains are remarkably plastic, giving us the ability to learn from our daily experiences and to use memories of these experiences to guide our behavior. My lab studies coordination of activity in neural circuits distributed across multiple brain regions that enable animals to learn, to store and retrieve memories, and to make decisions. I will present recent findings that elucidate the role of prominent neurophysiological activity patterns in coordinating ensembles of neurons in the hippocampus and prefrontal cortex to support learning and memory-guided decision making. We show that these activity patterns underlie state-dependent coordination of neural ensembles at multiple timescales to mediate memory-guided behavior in rodent spatial memory models. These results suggest a framework in which multiple-timescale mechanisms coordinate cell assemblies for governing cognitive functions and highlight a critical link between neural dynamics and cognition.

Priya Rajasethupathy, MD, PhD

The Rockefeller University

Laboratory of Neural Dynamics and Cognition

Exploring genetic contributions to variation in attention and short-term memory

Monday, November 6, 2023 3:00 PM Hosted by Dr. Lief Fenno

Priya Rajasethupathy at Rockefeller ↗

Abstract

How are transient stimuli converted into lasting internal representations? And are there unique strategies to achieve memory on different time scales. Our lab addresses these questions by bridging functional genomics with systems neuroscience to provide cross-disciplinary insights. On one hand, we perform genetic mapping in outbred mice for unbiased discovery of genes, cell types, and circuits relevant for memory across different time scales. In parallel, we develop and apply methodologies to record and manipulate high resolution neural activity from relevant circuits in the behaving animal. In this talk, I will discuss how these approaches have led to insights into the genetic contributions and long-range circuit dynamics that facilitate both short- and long- term memory.

Gek-Ming Sia, PhD

UT Health San Antonio

Department of Pharmacology

Immune mechanisms that shape brain circuitry in health and disease

Monday, November 27, 2023 3:00 PM Hosted by Dr. Jennifer Donegan

Gek-Ming Sia at UT Health ↗

Abstract

The brain has historically been considered an immune-privileged organ devoid of immune activity. However, there is mounting evidence that the complement cascade of the innate immune system acts through microglia in the brain to selectively prune synapses during brain development and disease. In this talk, I will present two projects from our lab. The first project examines the role of a complement inhibitor in regulating synapse elimination during brain development. The second project examines how chronic stress acts through microglial phagocytosis of synapses to cause synapse loss in the prefrontal cortex and working memory deficits. Taken together, our work shows that immune processes in the brain can directly modify neural circuits and organism behavior through removal of synapses.

David Paydarfar, MD

Dell Medical School, Neurology

The University of Texas at Austin

Noise-sensitive neural oscillators: theory and applications for their control

Monday, January 22, 2024 3:00 PM Hosted by Dr. Laura Colgin

Chair, Dell Med Neurology ↗

Abstract

Neural oscillations are essential for many physiological control systems – for example regulating breathing, behavioral states, and locomotion. Neural oscillations are also implicated in many disease states. I will present and discuss theoretical, experimental, and clinical observations on the initiation and termination of neural rhythms at the neuronal, circuit, and systems levels. The findings reveal how small appropriately tuned noisy inputs could silence a neural oscillator or, conversely, could promote rhythmic activity. Noise-sensitive neurons have intrinsic properties that yield interesting physiological properties on the edge of a bifurcation, affording remarkable adaptive properties to circuits that require rapid and energy-efficient on-off switching. I will discuss clinical examples including rhythmic discharges of neurons in epilepsy and episodic severe apnea in preterm infants. Mathematical and computational methods can provide important insights into the etiology and treatment of oscillopathies.

Alice Ting, PhD

Stanford University

Departments of Biology & Genetics

Engineering proteins to map and manipulate cells

Monday, February 19, 2024 3:00 PM Hosted by Dr. Kristen Harris

Ting Lab ↗

Abstract

Biological function is orchestrated through the collective action of molecules and cells. Our laboratory develops technologies to study molecular and cellular assemblies at high spatial and temporal resolution in living cultures and organisms. I will describe recent technologies from our laboratory including TransitID for unbiased mapping of proteome trafficking within cells and between cells, light-regulated proximity labeling, and new enzymes for proximity labeling created through machine learning. I will also describe new technologies for manipulating cellular behavior in response to specific external cues, through the use of engineered synthetic receptors.

Nicole Calakos, MD, PhD

Duke University School of Medicine

Department of Neurobiology

The few but mighty: Striatal interneuron plasticity in habit formation

Monday, March 25, 2024 3:00 PM Hosted by Dr. Bob Messing

Calakos Lab ↗

Abstract

While long-term synaptic plasticity of glutamatergic synapses onto projection neurons is a core component supporting many adaptive behaviors, increasingly the multi-site distribution of circuit plasticity is recognized. I will discuss mechanisms by which striatal interneurons contribute to adaptive behaviors. Striatal fast-spiking interneurons (FSI) undergo experience-dependent plasticity in the process of instrumental task learning and habit formation. Insights to the molecular mechanisms and circuit consequences of FSI adaptations supporting habit learning will be presented.

Srivatsun Sadagopan, PhD

University of Pittsburgh

Center for Neuroscience

Auditory cortical computations for robust vocalization recognition

Monday, April 1, 2024 3:00 PM Hosted by Nicholas Priebe

Sadagopan Lab ↗

Abstract

Ethologically important sounds such as human speech and animal vocalizations are typically produced with tremendous between-subject and inter-trial variability. These sounds are also encountered in highly variable listening environments. A central function of auditory processing is to generalize over this variability and group sounds that carry distinct behavioral meanings into discrete categories. In this talk, I will describe a theoretical model of how such categorization can be achieved in the case of animal vocalizations. I will present electrophysiological evidence supporting this theoretical model, and using guinea pigs performing a vocalization categorization task, demonstrate that categorization behavior is also consistent with this model. Finally, I will discuss how the model can generate testable experimental predictions, ongoing efforts to test some model predictions using electrophysiological recordings in behaving animals, and how the model can generate insight into speech processing. In summary, these theoretical and experimental results will propose a biologically interpretable hierarchical model in which early acoustic representations are transformed into downstream goal-directed representations that support specific behaviors.

Alexander Jackson, PhD

Unviersity of Connecticut

Department of Physiology and Neurobiology

Molecular building blocks of lateral hypothalamic circuits

Monday, April 8, 2024 3:00 PM Hosted by Dr. MacKenzie Howard

Jackson Lab ↗

Abstract

My research program is focused on defining the cellular architecture and function of interconnected and interrelated neuromodulatory circuits in the lateral hypothalamic area (LHA). The LHA is critical in the regulation of fundamental behavioral states such as sleep, wakefulness, energy balance, motivated behavior and stress. A significant obstacle to developing a detailed, circuit-level picture of LHA circuit function is a significant gap in our understanding of the constituent neuronal cell types that populate this region. Delineating this underlying population structure is a critical first step in working out patterns of synaptic connectivity, neurochemical signaling within neural circuits, relationship to behavior and circuit-level dysfunction in disease. In the first part of my talk, I will discuss our recent efforts directed at using single-cell biology and circuit-mapping to develop cellular taxonomies of molecularly-distinct neuronal cell types in this region of the hypothalamus. In the second part of my talk, I will share how we have been leveraging our single cell atlas data to probe a suite of molecules that may have a role in the form and function of synapses in a neuropeptidergic LHA population involved in the regulation of sleep and wakefulness.

Jayeeta Basu, PhD

New York University

Department of Neuroscience & Physiology

Hippocampus shapes cortical output and novelty coding through a direct feedback circuit

Monday, April 15, 2024 3:00 PM Hosted by INS trainee, Mandi Severson

Basu Lab ↗

Abstract

To extract behaviorally relevant information from our surroundings, our brains constantly integrate and compare incoming sensory information with those stored as memories. Cortico-hippocampal interactions could mediate such interplay between sensory processing and memory recall but this remains to be demonstrated. Recent work parsing entorhinal cortex-to-hippocampus circuitry show its role in episodic memory formation and spatial navigation8. However, the organization and function of the hippocampus-to-cortex back-projection circuit remains uncharted. We combined circuit mapping, physiology, in vivo two photon imaging and behavior with optogenetic manipulations, and computational modeling to reveal how hippocampal feedback modulates cortical sensory activity and behavioral output. Here we show a new direct hippocampal projection to entorhinal cortex layer 2/3, the very layer that projects multisensory input to the hippocampus. Our finding challenges the canonical cortico-hippocampal circuit model where hippocampal feedback only reaches entorhinal cortex layer 2/3 indirectly via layer 5. This direct hippocampal input integrates with cortical layer 1 inputs in layer 2/3 neurons to heterosynaptically drive their plasticity and spike output. In vivo imaging validates that hippocampus actively modulates behaviorally relevant cortical activity during reward and spatial coding. During freely moving behavior, silencing the hippocampal input to layer 5 impairs encoding of novel objects and where as silencing the hippocampal input to layer 2/3 impairs memory recall of objects and their locations. Through the sensory-memory feedback loop, hippocampus can update real-time cortical sensory processing, efficiently and iteratively, thereby imparting the salient context for adaptive learned behaviors with new experiences.

Madineh Sedigh-Sarvestani, PhD

Cornell University

Department of Neurobiology and Behavior

Using the body to understand sensory processing in the brain

Monday, April 29, 2024 3:00 PM Hosted by Dr. Xuexin Wei

Sarvestani Lab ↗

Abstract

Advances in neuro-imaging methods have allowed neuroscientists to uncover enigmatic mathematical structures in sensory circuits of the brain, for instance smooth mapping of spatial location and edge orientation in primary visual cortex. However, not all species exhibit similar organization in analogous brain regions, pointing to a need for cross-species comparisons in the search for universal principles of neural organization. Using tree shrews, a non-typical animal model, I discovered a complex organization of spatial location in visual cortex. I’ll discuss these findings and how they help unify seemingly conflicting structures in the visual system of rodents and primates, especially when we consider their visual experience. In the second part of the talk, I’ll discuss my lab’s ongoing efforts to understand how the structure of sensorimotor circuits is shaped by the structure of sensorimotor experience, which is significantly constrained by bodily movements. These efforts require an embedded approach to the study of neural circuits, one that considers how brains and bodies work together to serve an animal’s specific needs.

Neuroscience Seminar Series

To subscribe to our Seminars mailing list, please visit https://utlists.utexas.edu/sympa/info/neu-seminars and click on "Subscribe" in the left column.

For any inquiries, you may contact Neuro.Seminar.Series@austin.utexas.edu.

Roger Nicoll, MD

A molecular machine for memory

Abstract

Claudia Lucchinetti, MD

Multimodal Imaging of Multiple Sclerosis Pathlogy: From Structure to Function

Abstract

Erik Jorgensen, PhD

Synaptic Transmission in Time (ms) and in Space (nm)

Abstract

Krešimir Josić, PhD

Plasticity, balance and the structure of neuronal networks

Abstract

Kristina Nielsen, PhD

Representation of 3D and 2D shape in visual area V4

Abstract

Shantanu Jadhav, PhD

Neural coordination mechanisms for memory-guided behavior

Abstract

Priya Rajasethupathy, MD, PhD

Exploring genetic contributions to variation in attention and short-term memory

Abstract

Gek-Ming Sia, PhD

Immune mechanisms that shape brain circuitry in health and disease

Abstract

David Paydarfar, MD

Noise-sensitive neural oscillators: theory and applications for their control

Abstract

Alice Ting, PhD

Engineering proteins to map and manipulate cells

Abstract

Nicole Calakos, MD, PhD

The few but mighty: Striatal interneuron plasticity in habit formation

Abstract

Srivatsun Sadagopan, PhD

Auditory cortical computations for robust vocalization recognition

Abstract

Alexander Jackson, PhD

Molecular building blocks of lateral hypothalamic circuits

Abstract

Jayeeta Basu, PhD

Hippocampus shapes cortical output and novelty coding through a direct feedback circuit

Abstract

Madineh Sedigh-Sarvestani, PhD

Using the body to understand sensory processing in the brain

Abstract