Zoom Link：619 713 0777
Password：1202
Time: 9:00-10:00 on Thu., Dec.2, 2021
Speaker：Tongchao Li Department of biology ,Stanford University
Topic:
Multi-strategic investment of fly olfactory circuit assembly through time-lapse imaging and single-cell RNA sequencin
Abstract：
The development of brain is featured by the extremely precise connectivity formed by enormous number of neurons. In the fly olfactory circuit axons of 50 types of olfactory receptor neurons (ORNs) form precise one-to-one connection with dendrites of 50 types of projection neurons (PNs) in stereotypical glomeruli. To understand how ORN axons make correct connections with synaptic PN dendrites, we recently established an explant based time-lapse imaging system. Using this system we comprehensively imaged the targeting process of 90 single axons from 30 types of ORNs. This led to many interesting discoveries in the cell biological bases underpinning dynamic neural targeting. Using single-cell RNA sequencing technology, we also profiled the transcriptomes in developing ORNs, from which we identified diverse regulatory strategies for olfactory receptor expression and axon targeting. Together these two powerful techniques will help us understand how specific genes regulate precise targeting in the development of neuron circuits.
Biography：
Tongchao Li received his bachelor’s degree from the Biological Science and Biotechnology Department of Tsinghua University in 2009. During his undergraduate research he studied the mechanisms of flagellar assembly and disassembly in Chlamydomonas in Dr. Junmin Pan’s lab at Tsinghua. He then moved to Baylor College of Medicine in Houston, where he earned his Ph.D. degree from the program of Developmental Biology in 2016. During his PhD he joined the laboratories of Dr. Hugo Bellen and Dr. Andrew Groves, and characterized the evolutionarily conserved genetic mechanism underlying the development of the Drosophila auditory organ. He is currently a postdoctoral fellow in the Department of Biology at Stanford University from the laboratory of Dr. Liqun Luo since 2016. In the Luo lab, Dr. Li is using explant based time-lapse imaging and single-cell RNA sequencing to study the assembly of the olfactory circuit in Drosophila.
Time: 10:00-11:00 on Thu., Dec.2, 2021
Speaker：Yunlong Tao Waisman center, University of Wisconsin - Madison
Topic:
Neural differentiation and regeneration
Abstract：
My research interests focus on studying human nervous system development, investigating the pathogenic mechanisms of neurological diseases and developing cell therapies to treat neurodegenerative diseases. My main research model is the pluripotent stem cells (PSC). The neural differentiation from human PSC recapitulates the human neural development processes in vitro, which provides unique advantages to study human nervous system development and neurological diseases under the human genetic background. Additionally, PSC derived neural cells hold great potentials to treat neurodegenerative diseases by replacing the degenerated cells. For example, degeneration of dopamine (DA) neurons in the midbrain underlies the pathogenesis of Parkinson’s disease (PD). Supplement of DA via L-Dopa alleviates motor symptoms but does not prevent the progressive loss of DA neurons. Cell therapy has been tried to treat PD in open-label and double-blinded clinical trials using human fetal tissues. However, the outcomes are mixed, primarily due to the undefined and unstandardized donor tissues. Generation of DA progenitor from patient induced PSC enables standardized and unlimited cell source for PD without ethic concerns. In this seminar, I will present my research about studying human retinal development, generation of norepinephrine neurons and developing autologous cell therapy for PD in non-human primates using PSC.
Biography：
Dr. Yunlong Tao is Assistant Scientist in the Waisman center at University of Wisconsin – Madison. He received his B.S. degree from University of Science and Technology of China in 2008 and obtained his PhD from University of Chinese Academy of Sciences (Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences) in 2014. During his postdoc training period with Dr. Su-chun Zhang at University of Wisconsin – Madison, he has been using human pluripotent stem cell as model to study the process of human nervous system development, dissect out the mechanisms underlying neurological disorders and develop cell therapies for neurodegenerative diseases.
Time: 11:00-12:00 on Thu., Dec.2, 2021
Speaker：Guang Chen Department of Neuroscience, Baylor College of Medicine
Topic:
Frontal network modular organization for robust and flexible behavior
Abstract：
Robust and flexible behavior is critical for human and/or animal survival in noisy and dynamically changing environments. Healthy behavior would require both high stability (robustness) and flexibility. However, there is a dilemma between cognitive stability and flexibility, where one’s increase results in the other’s decrease. How does the brain maintain stability and flexibility as high as possible? Neural network modular organization may be a general principle to implement high stability and flexibility together. My recent studies discovered a novel modular organization in frontal cortical regions for robust short-term memory behavior. Through these studies, I established an experiment and analysis framework to measure neural circuit functional/effective connection and uncover network organization underlying complex cognitive behavior. In the future, I’ll systematically dissect brain-wide multi-regional network organization for robust short-term memory. I’ll further develop new cognitive/motor control behavior tasks on mice to examine neuronal network mechanisms of cognitive/motor stability and flexibility. Ultimately, I aim to develop new neuromodulation/BMI technologies to cure brain diseases that exhibit imbalance or deficits of stability and flexibility. My studies may also facilitate the design of new brain-inspired algorithms that leverage modular organizing principles.
Biography：
Dr. Guang Chen graduated from Shanghai Jiao Tong University in 2009 and completed his Ph.D. degree in the Institute of Neuroscience, Chinese Academy of Sciences, Shanghai in 2016. He is currently a postdoctoral associate in the department of neuroscience at Baylor College of Medicine. His research is focusing on dissecting neural circuit/network mechanisms of neural activity dynamics underlying cognitive and motor functions. He is an expert at using high-density silicon/neuropixels probes, two-photon calcium imaging, and optogenetic tools to record and perturb a large number of neurons during the complex behavior of healthy and unhealthy animals. He has published multiple papers in high-impact journals, such as Cell, Neuron, and eLife.
Time: 13:00-14:00 on Thu., Dec.2, 2021
Speaker：Steven Boeynaems Stanford University
Topic:
Multi-strategic investment of fly olfactory circuit assembly through time-lapse imaging and single-cell RNA sequencin
Abstract：
Cellular stress is a universal feature of Life, and is deeply implicated in the etiology of human disease. In the past few years, biomolecular condensates have emerged as key stress-responsive compartments, that allow cells to sense and respond to stress. Additionally, perturbations in these same biomolecular condensates are associated with several neurodegenerative diseases and aging. However, it is still unclear whether such BMC alterations are adaptive or actually driving dysfunction. In my work, I uncovered a prime role for perturbed biomolecular condensation and stress signaling in a spectrum of neurodegenerative conditions that centers around amyotrophic lateral sclerosis. Yet, many questions remain as to how exactly these defects underlie pathogenesis and how we can therapeutically target them, as currently biomolecular condensates present a largely undruggable space. The stress-induced defects underlying aging and disease are not exclusively limited to humans. Therefore, countless organisms not only cope with but thrive in the face of stress, and have evolved a wide array of approaches to mitigate cellular stress. Hence, a better understanding on how biomolecular condensates intersect with stress signaling in other—stress-tolerant—organisms, will highlight novel ways to modulate them in human disease. I will discuss how such an evolution-guided approach, in combination with innovative proteomics methods and machine learning is helping us to uncover how biomolecular condensates are regulated in health and disease. Additionally, I will show that these approaches provide us with novel synthetic biology tools that allow us to develop biomimetic designer condensates for drug screens and disease modeling. In all, my work translates fundamental insights into condensate biology from plants, bacteria and venomous animals to humans, and inspires new ways of how we think about neurodegenerative disease and therapy.
Biography：
Steven Boeynaems is a postdoctoral fellow at Stanford, whose work focuses on our understanding of how cells and organisms regulate their proteome as a way to sense and respond to cellular stress, which remains a poorly understood area of cell biology. Over the years, this has led him to study a variety of stress paradigms in physiology and disease with an emphasis on the role of tandem repeats, intrinsically disordered proteins, and biomolecular condensates. Steven’s goal is to create biosynthetic and -mimetic tools for synthetic biology, and to translate fundamental biological insights into novel therapeutic approaches for human diseases.
Time: 14:00-15:00 on Thu., Dec.2, 2021
Speaker：Fei Hu University of California,Berkeley
Topic:
Neural Circuits Controlling Visual Attention
Abstract：
At any given moment, we are constantly bombarded with messages. Selective attention, the ability to pay attention to important things but ignore the rest, is critical for navigating everyday life. Decades of studies in human and non-human primates have identified multiple brain regions important in attentional modulation. Due to the difficulty of dissecting neural circuits in primates, the neuronal mechanisms underlying attentional modulation and the origin of attention signals remain poorly understood. Mice provide a powerful animal model for addressing such circuit-level questions, but their cognitive capability for selective attention was demonstrated only very recently. Our recent work showed that corticotectal pyramidal neurons in the mouse anterior cingulate cortex exert powerful top-down modulation of visually guided behavior and visual cortical responses through collateral projections to two subcortical targets: the motor layers of the superior colliculus and pulvinar thalamus. Moreover, we established an auditory cue-directed visual spatial attention task for head-fixed mice that induces powerful attentional modulation of visual cortical responses, similar to that observed in primates. We identified an auditory cue-evoked response in the nucleus of the brachium of the inferior colliculus, which is faithfully transmitted to the superior colliculus, as the key attention signal that controls both the behavioral performance and attentional modulation in the superior colliculus and visual cortex.
Biography：
Dr. Fei Hu graduated from Huazhong University of Science & Technology and received his bachelor’s degrees with dual majors in biotechnology and law in 2009. He obtained his Ph.D. degree at Peking Union Medical College, Tsinghua University and National Institute of Biological Sciences, Beijing in 2014, supervised by Dr. Minmin Luo. His Ph.D. work primarily focused on how peptides and small molecules modulate the neurotransmission in the mysterious neural pathway from the medial habenula in the epithalamus to the interpeduncular nucleus in the midbrain. Since 2015, he has been a postdoctoral fellow working with Dr. Yang Dan at University of California, Berkeley. His postdoctoral research uncovered the circuit mechanism for how corticotectal pyramidal neurons in the mouse anterior cingulate cortex exert powerful top-down modulation of visual processing. He further developed a novel auditory cue-directed visual spatial attention task for mice and identified a source of attention signal in the midbrain. He is also part of the International Brain Laboratory, a team performing the largest scale electrophysiological recording project with high quality standards to ensure reproducibility across labs.
Time: 15:00-16:00 on Thu., Dec.2, 2021
Speaker：Xinyu Zhao Janelia Research Campus, HHMI
Topic:
Cellular Mechanisms Underlying Context-Dependent Memory of Sensory Cues in the Hippocampus
Abstract：
Memory defines who we are. One signature of memory encoding is that sensory information is bound with specific contexts, to disambiguate distinct experiences containing similar sensory cues. Hippocampus is a critical brain structure for episodic memory, where context-dependent firing has been observed. What is the input dynamics underlying the context-dependent firing and what form of plasticity is responsible for generating it? I addressed these questions by combining in-vivo intracellular recordings, in-vivo extracellular recordings, and spatial navigation tasks in virtual reality. My results demonstrate that the rapid synaptic plasticity, induced by dendritic calcium spikes, can reliably convert silent cells into context-dependent place cells in the CA1 subregion of the mouse hippocampus. Surprisingly, the membrane potential depolarization showed a nearly all-or-none dynamics for different contexts, indicating the context dependency in CA1 is inherited from its presynaptic areas. Recordings in CA3 support this hypothesis. At the end, I will talk about preliminary results using similar approaches to investigate hippocampus’ role in more complex cognitive functions beyond learning simple cue-reward associations.
Biography：
Dr. Xinyu Zhao graduated from Tsinghua University with Bachelor and Master’s degrees, working on Drosophila olfactory memory in Dr. Yi Zhong’s lab. He then did his Ph.D. research in Dr. Jianhua Cang’s lab at Northwestern University, where he conducted physiological studies in various brain areas in the mouse visual system. His research contributes to the understanding of binocular integration, thalamic orientation selectivity, and the modulation of looming-evoked visual responses. Following Ph.D., he worked at Janelia Research Campus, Howard Hughes Medical Institute, with Dr. Nelson Spruston and Dr. Jeff Magee. His research has focused on the synaptic plasticity mechanism responsible for memory encoding in the hippocampus, using a combination of electrophysiology, virtual reality, and computational tools.