Physiology and Biophysics

Seminars

Apr
6
Thu
2017
2017 Hille Lecture – Thomas Schwarz @ Foege Auditorium
Apr 6 @ 4:00 pm – 5:00 pm

Moving and Removing Axonal Mitochondria

Thomas L. Schwarz, PhD
Professor Neurology
F.M. Kirby Center for Neurobiology
Children’s Hospital, Boston
and Dept. of Neurobiology, Harvard Medical School

Time: 4:00PM

Location: Foege Auditorium, GNOM S060

seminar abstract: Mitochondria are dynamic organelles.  In every cell they move and undergo fission and fusion.  Their distribution and associations with the cytoskeleton change in response to many signals, including the mitotic cell cycle.  In addition, because neurons look like no other cell in the organism, with axons of up to a meter in humans, mitochondrial motility is particularly crucial to the survival of the neuron. The neuron also needs to clear away damaged mitochondria efficiently wherever in the cell they may arise.  Not surprisingly then, defects in the transport machinery of neurons and in their mechanisms for removing damaged mitochondria have been linked to several neurodegenerative diseases, including ALS and Parkinson’s disease.  This talk will present the evidence for a motor/adaptor complex that is responsible for and regulates the movement of mitochondria and will discuss how that movement is regulated by the cell cycle, Ca++, and glucose.  We will look at the operation of two proteins PINK1 and Parkin that are mutated in forms of Parkinson’s disease and examine how these proteins operate in axons to clear away damaged mitochondria that might otherwise compromise the health of the cell.  Particularly in the case of mitophagy, we will consider the special challenges posed for neurons by their extended geometry and the difficulty of having a PINK1-dependent pathway operating far from the soma.

 

Apr
13
Thu
2017
PBIO seminar – Rui Chang @ HSB G-328
Apr 13 @ 9:30 am – 10:30 am

From body to brain: control of autonomic physiology by the sensory vagus nerve

Rui Chang, Ph.D.
Department of Cell Biology
Harvard Medical School

Seminar abstract:

Cardiac, respiratory, and other autonomic functions are precisely controlled by the nervous system, yet many autonomic reflexes remain poorly characterized at a molecular and cellular level. The sensory vagus nerve is a major conduit between body and brain, and is critical for many autonomic physiology. Using a genetic approach, we molecularly deconstructed the vagus nerve, and successfully identified neuron populations that are critically involved in respiratory physiology and digestive functions. We further elucidated the molecular mechanism for lung inflation-mediated apnea. Together, these findings lay the groundwork for a molecular dissection of respiratory and gastrointestinal physiology.

Apr
20
Thu
2017
PBIO seminar – Claudia Moreno @ HSB G-328
Apr 20 @ 9:30 am – 10:30 am

Couple, amplify, fire!

Coupling of L-type calcium channels and excitability

L-type CaV1.2 and CaV1.3 calcium channels are key players in the generation and regulation of electrical activity in different cell types, including neurons and myocytes. In the pacemaker cells of the heart, the spike of the action potential that initiates each heartbeat depends entirely on the entry of calcium through these channels. Recently, we discovered a novel cooperative gating mechanism, on both CaV1.2 and CaV1.3 channels, which facilitates calcium entry and modulates the excitability of ventricular cardiomyocytes and neurons. We found that these channels establish a calcium-dependent physical interaction via their c-termini, which results in an increase in their open probability. Our more recent project aims to answer two new questions: Do CaV1.2 and CaV1.3 channel undergo functional coupling in the pacemaking cells of the heart? And, if so, is this coupling modulated by physiological stimuli? Our new results point to a mechanism by which beta-adrenergic signaling increases the coupling of CaV1.2 channels in the pacemaker cells. These exciting results add to our understanding on how the sympathetic nervous system increases heart rate.

 

Claudia Moreno, Ph.D.
Department of Physiology and Membrane Biology
School of Medicine
University of California, Davis

host: Stan Froehner

Apr
27
Thu
2017
PBIO Seminar Series: Chris Liu @ HSB G-328
Apr 27 @ 9:30 am – 10:30 am

“Molecular Signaling Mechanisms of Cardiac Remodeling and Heart Failure”

Chris Liu

University of Washington
Dept of Physiology & Biophysics

 

host: Stan Froehner

May
4
Thu
2017
PBIO Seminar Series: Dr. Felix Viana @ HSB G-328
May 4 @ 9:30 am – 10:30 am

“Molecular physiology of cold-activated TRP channels”

Dr. Félix Viana

Tenured Investigator of the Spanish Council for Scientific Research (CSIS)

Instituto de Neurociencias de Alicante  Institute of Neurosciences, Alicante (Spain)

Visiting Scholar in the Department of Biological Structure, UW

Transient receptor potential (TRP) channels are a family of cationic channels with important roles in many aspects of sensory physiology, from vision to taste. Several of these channels are highly sensitive to temperature and have been shown to play critical roles in thermoreception, thermoregulation and pain. I will provide an overview of our work with two cold-activated channels, TRPA1 and TRPM8, highlighting their differential function in cold transduction, thermoregulation and nociception, and some newly discovered pathophysiological roles outside the nervous system.

host: Bertil Hille

May
11
Thu
2017
PBIO Seminar Series: Daniel Polley @ HSB G-328
May 11 @ 9:30 am – 10:30 am

Rebooting sensory processing after afferent loss: probing the capabilities and limitations of adult cortical plasticity 

Daniel Polley, PhD

Harvard Medical School

Massachusetts Eye and Ear Infirmary

host: Ed Rubel

abstract:

Following a near-complete loss of auditory nerve fibers that convey signals from the cochlea to the brain, all evidence of central sound processing grinds to a halt. Over the ensuing weeks, neurons at higher stages of central auditory processing increase the gain on the small fraction of remaining inputs and restore perceptual awareness and normative rate coding, even when markers of brainstem processing indicate complete deafness. I will describe our efforts to understand the mechanisms and limitations of this “cortical amplifier” that supports a partial compensatory plasticity. The second half of the talk will address whether further gains of function might be possible through auditory training tasks that activate cholinergic neurons in the basal forebrain. In particular, we are motivated to discover ways to ‘de-noise’ cortical representations of stimuli embedded in high levels of background noise. These experiments describe a multiplexed encoding of auditory stimuli and behavioral reinforcement signals in cholinergic neurons of Nucleus Basalis that project to the auditory cortex. We ask how these neurons are activated during auditory learning, first through simple auditory fear conditioning and ultimately through complex audiomotor tasks that generate high levels of sensory prediction errors. We conclude by showing how training on closed-loop audiomotor behavioral tasks can broadly enhance cortical and perceptual processing of faint sounds near the noise floor both in unit recordings from the mouse auditory cortex and through measurements of speech processing in elderly human subjects with profound hearing loss.

Jun
15
Thu
2017
PBIO Seminar Series: Jean Claude Beique @ HSB G-328
Jun 15 @ 9:30 am – 10:30 am
Jun
20
Tue
2017
2017 Crill Lecture – William Bialek @ D-209 HSB
Jun 20 @ 4:00 pm – 5:00 pm

Thinking about a thousand neurons

William Bialek
John Archibald Wheeler/Battelle Professor in Physics
Princeton University

Sep
21
Thu
2017
PBIO Seminar Series: Andrei Smertenko @ HSB G-328
Sep 21 @ 9:30 am – 10:30 am

How plants conquer the space: the cell’s flying plates

Plant cytokinesis is orchestrated by a specialized structure, the phragmoplast. The phragmoplast first occurred in representatives of Charophyte algae and then became the main division apparatus in land plants.  Major cellular activities, including cytoskeletal dynamics, vesicle trafficking, membrane assembly, and cell wall biosynthesis, cooperate in the phragmoplast under the guidance of a complex signaling network. My research focuses on the self-organization processes that govern phragmoplast functions. I will give a general overview of plant cytokinesis, and present our recent data on the gamma-tubulin independent microtubule nucleation by the plant-specific protein MACERATOR and a conserved member of TPX2 protein family.

Andrei Smertenko, Ph.D.
Assistant Professor, Molecular Plant Sciences
Washington State University

host: Linda Wordeman

Oct
12
Thu
2017
PBIO Seminar Series: Liangyi Chen @ HSB G-328
Oct 12 @ 9:30 am – 10:30 am

High spatiotemporal resolution, three-dimension fluorescence imaging of biological samples in vivo

Dr. Liangyi Chen
Professor
Laboratory of Cell Secretion and Metabolism
Institute of Molecular Medicine,
Peking University, Beijing, China

Host: Bertil Hille

Abstract: I will give two stories. (i) One story describes unpublished ultrasensitive Hessian structured illumination microscopy that enables ultrafast and long-term super-resolution (SR) live-cell imaging. At a photon dose one order less than point-scanning microscopy, Hessian-SIM has achieved 88-nm and 188-Hz spatial-temporal resolution for live cells imaging and lasted thousands of images without artifacts. Operating at 1 Hz, Hessian-SIM enables hour-long, time-lapse SR imaging with mitigatable photobleaching, highlighting the possibility of achieving SR imaging with commonly used fluorophores for an unlimited period of time. (ii) The second story is our recent Nature Methods paper, our invention of the fast high-resolution miniature two-photon microscope for brain imaging in freely-behaving mice at the single-spine level. With a headpiece weighing 2.15 g and a new type of hollow-core photonic crystal
fiber to deliver 920-nm femtosecond laser pulses, the mini-microscope is capable of imaging commonly used biosensors at high spatiotemporal resolution (0.64 μm laterally and 3.35 μm axially, 40 Hz at 256 × 256 pixels). It compares favorably with benchtop two-photon microscopy and miniature wide-field fluorescence microscopy in the structural and functional imaging of Thy1-GFP- or GCaMP6f-labeled neurons. Further, we demonstrate its unique application and robustness with hour-long recording of neuronal activities down to the level of spines in mice experiencing vigorous body and head movements or engaging in social interaction.

Oct
26
Thu
2017
PBIO Seminar Series: Brian Kalmbach @ HSB G-328
Oct 26 @ 9:30 am – 10:30 am

“Of Mice and Men: Intrinsic Membrane Properties of Human Cortical Pyramidal Neurons”

Brian Kalmbach, Ph.D.

Allen Institute for Brain Science

host: Nikolai Dembrow

Nov
2
Thu
2017
2017 Lamport Lecture – Gilles Laurent @ T-739 HSB
Nov 2 @ 4:00 pm – 5:00 pm

Evolution and brain computation

I will introduce our work towards identifying principles of brain function and computation, focused on using comparative approaches and exploiting unusual model systems (reptiles, cephalopods) to study sleep, texture perception and cerebral cortex evolution.

Gilles Laurent, PhD, DVM

Director

Max Planck Institute for Brain Research

http://www.brain.mpg.de/home/

 

4:00 PM

Location: T-739, HSB

 

host: Stan Froehner

Dec
7
Thu
2017
PBIO Seminar Series: Nikolai Dembrow @ HSB G-328
Dec 7 @ 9:30 am – 10:30 am

Title: TBA

Nikolai Dembrow, PhD

host: Stan Froehner

Jan
9
Tue
2018
PBIO Seminar: Rishidev Chaudhuri @ HSB G-328
Jan 9 @ 9:30 am – 10:30 am

“Cognitive manifolds and their dynamics across states and areas”

Rishidev Chaudhuri, PhD.
Center for Learning & Memory
The University of Texas at Austin

Host: Stanley C. Froehner

Jan
16
Tue
2018
PBIO Seminar: Ashok Litwin-Kumar, PhD @ HSB G-328
Jan 16 @ 9:30 am – 10:30 am

“Randomness and structure in neural representations for learning”

Ashok Litwin-Kumar, PhD
Center for Theoretical Neuroscience
Columbia University

Host: Stanley C. Froehner

Jan
25
Thu
2018
Canceled – Seminar: Amy Bastian, PhD @ HSB G-328
Jan 25 @ 9:30 am – 10:30 am

Canceled

Dr. Bastian’s seminar will be rescheduled for a later date.

 

 

Learning and Relearning Movement

Human motor learning depends on a suite of brain mechanisms that are driven by different signals and operate on timescales ranging from minutes to years. Understanding these processes requires identifying how new movement patterns are normally acquired, retained, and generalized, as well as the effects of distinct brain lesions. The lecture focuses on normal and abnormal motor learning and how we can use this information to improve rehabilitation for individuals with neurological damage

Amy Bastian, Ph.D.
Professor of Neuroscience
Johns Hopkins University

 

Host: John Tuthill

 

Feb
1
Thu
2018
PBIO Seminar: Julijana Gjorgieva, PhD @ HSB G-328
Feb 1 @ 9:30 am – 10:30 am

Organizing principles in developing networks and sensory populations

Julijana Gjorgieva, PhD
Research Group Leader,
Max Planck Institute for Brain Research
Assistant Professor for Computational Neuroscience,
Technical University of Munich

Host: Stanley C. Froehner

Science in Medicine – Linda Wordeman @ D-209, HSB
Feb 1 @ 11:30 am – 12:30 pm

“Curious Intersection Between DNA Repair and Microtubule Dynamics”

Linda Wordeman, Ph.D
Professor
Physiology & Biophysics, UW

Dr. Linda Wordeman, Ph.D. uses high resolution live imaging to discover how changes in microtubule dynamics influence chromosome segregation and Chromosome INstability (CIN) in cancer cells. Dr. Wordeman will describe, mechanistically, how small changes in microtubule assembly dynamics promote CIN and reveal evidence for unexpected pathways, such as DNA damage repair, that may directly impact cellular mictrotubule dynamics.

Feb
5
Mon
2018
PBIO Seminar: Scott Linderman, PhD @ HSB G-328
Feb 5 @ 9:30 am – 10:30 am

Discovering Structure in Neural and Behavioral Data

Scott Linderman, PhD
Department of Statistics
Columbia University

 

Abstract:

New recording technologies are transforming neuroscience, allowing us to precisely quantify neural activity, sensory stimuli, and natural behavior.  How can we discover simplifying structure in these high-dimensional data and relate these domains to one another? I will present my work on developing statistical tools and machine learning methods to answer this question.  With two examples, I will show how we can leverage prior knowledge and theories to build models that are flexible enough to capture complex data yet interpretable enough to provide new insight. Alongside these examples, I will discuss the Bayesian inference algorithms I have developed to fit such models at the scales required by modern neuroscience.  First, I will develop models to study global brain states and recurrent dynamics in the neural activity of C. elegans.  Then, I will show how similar ideas apply to data that, on the surface, seem very different: movies of freely behaving larval zebrafish.  In both cases, these models reveal how complex patterns may arise by switching between simple states, and how state changes may be influenced by internal and external factors.  These examples illustrate a framework for harnessing recent advances in machine learning, statistics, and neuroscience.  Prior knowledge and theory serve as the main ingredients for interpretable models, machine learning methods lend additional flexibility for complex data, and new statistical inference algorithms provide the means to fit these models and discover structure in neural and behavioral data.

Host: Stanley C. Froehner

 

Feb
15
Thu
2018
PBIO Seminar Series: Bernhard Flucher @ HSB G-328
Feb 15 @ 9:30 am – 10:30 am

How and why are the currents of CaV1.1 calicum channels curtailied in skeletal muscle?

The presentation will include structure-function studies on CaV1 channels and analyses of the role of the calcium current in muscle fiber type specification and neuro-muscular junction formation using various mouse models.

Bernhard Flucher, PhD

Professor
Department of Physiology and Medical Physics
Medizinische Universität Innsbruck

host: Stan Froehner

May
3
Thu
2018
2018 Hille Lecture – Doris Tsao @ HSB G-328
May 3 all-day

Doris Tsao

Professor of Biology
HHMI Investigator
California Institute of Technology

time: TBD
location: TBD

host: Stan Froehner

May
10
Thu
2018
2018 Crill Lecture – J. Anthony Movshon @ HSB G-328
May 10 all-day

Time & Location TBA

J. Anthony Movshon, PhD

Professor, Department of Ophthalmology

Professor, Department of Neuroscience and Physiology

Jun
7
Thu
2018
PBIO Seminar Series: Amy Bastian @ HSB G-328
Jun 7 @ 9:30 am – 10:30 am

Learning and Relearning Movement

Human motor learning depends on a suite of brain mechanisms that are driven by different signals and operate on timescales ranging from minutes to years. Understanding these processes requires identifying how new movement patterns are normally acquired, retained, and generalized, as well as the effects of distinct brain lesions. The lecture focuses on normal and abnormal motor learning and how we can use this information to improve rehabilitation for individuals with neurological damage

Amy Bastian, Ph.D.
Professor of Neuroscience
Johns Hopkins University

Host: John Tuthill