seminars & bulletins

2014-2015
PBIO SEMINAR SERIES

THURSDAYS in G-328
10:30am (unless otherwise noted)
Refreshments follow the seminar

PBIO News

PBIO Special Events

Health Sciences Bulletin

Seminar Series archives

2011-2012 SEMINAR SERIES

October 18, 2011 
Special lecture: 2011 Lamport Lecture

Eric Gouaux
Senior Scientist, Vollum Institute, Investigator, HHMI, Vollum Institute, OHSU
"Architecture and mechanism of receptors and transporters at chemical synapses"

3:30pm, T-733

Signaling at chemical synapses involves transmitter release, detection and uptake. My talk will focus on the molecules involved in detection and uptake, molecules that are ligand-gated ion channels and sodium coupled transporters, respectively. I will describe the atomic structures and symmetries of an ionotropic glutamate receptor and a bacterial ortholog of the biogenic amine transporters. In combination with experimental data on receptor and transporter activity, I will put forth general principles by which we can now understand the molecular mechanisms of these molecules within the context of three-dimensional structure.

Host: Stan Froehner

October 27, 2011 

Duk-Su Koh
Research Associate Professor, Physiology & Biophysics, University of Washington
"Single cell analysis of stimulation-secretion coupling"

Host: Stan Froehner

November 03, 2011 

Bill Geisler
Professor of Psychology, University of Texas, Austin
"Natural Scene Statistics and Natural Tasks"

Host: Anitha Pasupathy/ Adrienne Fairhall
Co-hosting Department: Bio Structure, Computational Neuroscience

November 18, 2011 
Special lecture: Inaugural Sackler Biophysics Seminar

Thomas Portet
Sackler Scholar
"Effect of Mechanical Stresses on Lipid Membrane Phase Properties"

4pm, Foege N-130

Host: Department of Physiology & Biophysics

November 18, 2011 
Special lecture: Inaugural Sackler Biophysics Seminar

Tom Erez
Sackler Scholar
"Optimal Control of Biomechanical Simulations"

4pm, Foege N-130

Host: Department of Physiology & Biophysics

December 01, 2011 

Christine Portfors
Associate Professor, Washington State University - Vancouver
"Efficient encoding of behaviorally relevant sounds in the auditory midbrain of awake mice"

An important question in sensory neuroscience is what coding strategies and mechanisms are used by the brain to detect and discriminate among behaviorally relevant stimuli. Recent work in our laboratory has shown that neurons in the inferior colliculus (IC) of mouse show heterogeneous responses to natural vocalizations. Using information theoretic measures, we have shown that these heterogeneous responses contribute to efficient encoding of vocalizations at the level of the auditory midbrain. In this talk, I will discuss two neural mechanisms involved in creating these heterogeneous response properties; inhibition and cochlear distortions.

Host: Adrienne Fairhall

February 23, 2012 

Nathan Dascal
Sackler School Tel Aviv University
"Signaling from G protein coupled receptors to ion channels: the case of the muscarinic M2R-Gi/o-GIRK cascade"

Host: Bertil Hille
Co-hosting Department: Pharmacology

March 15, 2012 

Mehrdad Jazayeri
University of Washington
"A neural mechanism for tracking time in sensorimotor function"

Humans and animals infer temporal regularities, anticipate events, and plan their actions in time. The neural mechanisms that give rise to the measurement and production of time intervals are however unknown. I will summarize results from our psychophysical studies in humans and physiological studies in nonhuman primates in which we have begun to explore the behavioral and neural correlates of interval timing. Our psychophysical studies have shown that mechanisms of interval timing are remarkably plastic and are calibrated by the temporal statistics of the environment. Our physiological studies have focused on how timing information engages sensorimotor structures. I will describe results from an experiment in which we recorded neural activity in the parietal cortex (area LIP) of monkeys trained to measure and reproduce different sample intervals. In the measurement epoch, LIP responses had a nonlinear profile and firing rates at the end of the epoch increased monotonically with the sample interval. In the production epoch, activity increased linearly with a rate of rise that decreased monotonically with the sample interval. Remarkably, LIP responses predicted the trial-by-trial variability in the animalís behavior. Firing rates at the end of the measurement epoch were correlated with the slope of the ramping activity in the production epoch, which was in turn correlated with the animalís production interval. These results suggest that sensorimotor neurons receive ongoing information about the brainís estimate of elapsed time. Future work will exploit this finding to unravel the mechanisms by which neural circuits integrate timing information into sensorimotor function.

Host: Greg Horwitz

March 29, 2012 

Adrian KC Lee
University of Washington, Speech and Hearing Sciences/ILABS
"Using magnetoencephalography to study cortical network involved in auditory attention and more"

Understanding brain dynamics involved in many perception and cognitive tasks is of particular interest to scientists in the fields of speech & hearing, psychology, as well as neuroscience at large. Recently, an emerging neuroimaging technique known as magnetoencephalography (MEG) has arrived at the University of Washington. The MEG center is housed at the Institute for Learning & Brain Sciences (I-LABS). This technology is specifically suitable for capturing the dynamics of our brain mechanisms. In this talk, I will present our ongoing work on mapping the cortical network involved in auditory attention using a multimodal imaging approach (combining MEG with electroencephalography and magnetic resonance imaging). I will also talk about the new MEG course I have been teaching in the past year in which we have attracted students around campus from different departments (SPHSC / LING / PSYCH / NEUBEH / CSE / EE). This is an ongoing effort to foster an interdisciplinary environment such that students from neuroscience and engineering backgrounds can develop fruitful collaborative approaches to advance our understanding of brain dynamics using MEG.

Host: Adrienne Fairhall

April 05, 2012 

Michael Regnier
Professor & Vice-Chair, University of Washington Bioengineering
"Supercharging the Heart: Elevating 2 deoxy-ATP to Increase Myocardial Performance"

Striated muscle myosin is a promiscuous motor-enzyme, able to use a variety of nucleotides to different effectiveness. We have found that 2 deoxy-ATP enhances myosin activity and increases contractility of cardiac muscle at all levels of Ca2+ activation in demembranated myocardium. This occurs by enhanced myosin affinity for actin, coupled with faster myosin detachment at the end of the power-stroke. We recently reported that over-expression of Ribonucleotide Reductase (R1R2) can elevate cellular levels of dATP sufficiently to enhance cardiomyocyte contraction and relaxation. In both transgenic mouse and viral transduction models in mouse and rat, elevated cardiac dATP improves systolic function without impairing diastolic function, and our preliminary experiments demonstrate the ability to rescue systolic function of myocardium from infarcted hearts. Thus, myocardial elevation of dATP offers a potentially promising approach to the treatment of systolic heart failure.
Disclosure: Dr. Regnier holds a provisional patent application (UW ref. 45511.01US1) on R1R2 over-expression to improve cardiac contractile function.

Host: Fernando Santana

April 12, 2012 

Alex Merz
Associate Professor, University of Washington
"Velcro and clothespins: mechanisms of vesicle tethering, docking, and fusion in the Endolysosomal System"

Host: Stan Froehner and William N. Zagotta

April 19, 2012 

Eric Shea-Brown
Assistant Professor, University of Washington
"A mechanistic approach to multi-spike patterns in neural circuits"

There is a combinatorial explosion in the number of possible activity patterns in neural circuits of increasing size, enabling an enormous complexity in which patterns occur and how this depends on incoming stimuli. However, recent experiments show that this complexity is not always accessed -- the activity of many neural populations is remarkably well captured by simpler descriptions that rely only on the activity of single neurons and neuron pairs.

What is especially intriguing is that these pairwise descriptions succeed even in cases where circuit architecture seems likely to create a far more complex set of outputs. We seek a mechanistic understanding of this phenomenon -- and predictions for when it will break down -- based on simple models of spike generation, circuit connectivity, and stimuli. This also offers a chance to explore how much (and how little) beyond-pairwise spike patterns can matter to coding in different circuits.

As a specific application, we consider the empirical success of pairwise models in capturing the activity of ON-parasol retinal ganglion cells. We first use intracellular recordings to fully constrain a model of the underlying circuit dynamics. Our theory then provides an explanation for experimental findings based on ON-parasol stimulus filtering and spike generation properties.

Host: Adrienne Fairhall

April 26, 2012 

Jihong Bai
Assistant Member, Division of Basic Sciences, Fred Hutchinson Cancer Research Institute
"Regulation of Endophilin in synaptic vesicle endocytosis and its coupling to exocytosis"

Synaptic vesicle (SV) endocytosis is a highly specialized process with unique spatial and temporal controls. First, SV endocytosis occurs immediately after exocytosis and is accomplished locally at presynaptic sites. Second, the capacity of endocytosis is tightly coupled to the extent of exocytosis. These features suggest that components of the endocytic machinery are under direct control of SV exocytosis. My talk will focus on Endophilin, one of the founding members in the BAR-domain superfamily. I will discuss its role in bending membranes to promote SV endocytosis, as well as potential regulations allowing Endophilin to function with spatiotemporal precision during the SV cycle.

Host: Chip Asbury

May 03, 2012 

Ulli Bayer
University of Colorado School of Medicine
"CaMKII in the processing and storage of synaptic information"

The Ca2+/calmodulin(CaM)-dependent protein kinase II (CaMKII) can become partially Ca2+-independent ("autonomous") after autophosphorylation at T286, a mechanism described as form of molecular memory and indeed important in long-term potentiation (LTP) of synaptic strength and in memory. Contrary to previous hypothesis, our results indicate that autonomous CaMKII activity is required for information processing leading to LTP induction and memory formation, rather than in LTP maintenance or memory storage. However, our recent results indicate that storage of synaptic information may instead be mediated by CaMKII interaction with the NMDA-receptor complex. These effects and the underlying mechanisms will be discussed, also in connection with two clinically relevant findings: (i) inhibition of autonomous CaMKII activity was neuroprotective even when done hours after stroke model insults, and (ii) an intervention to interfere with the CaMKII/NMDA-receptor complex reversed pre-established addiction behavior.

Host: Andres Barria

May 09, 2012 
Special lecture: 2012 Hille Lecture

Rob Malenka
Pritzker Professor of Physchiatry & Behavioral Sciences, Stanford University
"Mechanisms and functions of synaptic plasticity"

3:30 pm, T-733

The activity-dependent modifications in neural circuits that underlie all forms of experience-dependent plasticity are thought to involve long-lasting changes in the strength of synaptic transmission at excitatory synapses. The most well characterized forms of such synaptic plasticity, NMDA receptor-dependent long-term potentiation (LTP) and long-term depression (LTD), have been implicated in playing important roles in several forms of adaptive and pathological learning and memory. An update of the mechanisms underlying these phenomena will be provided with a focus on new approaches that are allowing the detailed molecular mechanisms of LTP and LTD to be elucidated in unprecedented detail. The second part of the talk will provide an example of cell-type specific synaptic plasticity in mesolimbic dopamine circuitry and discuss the possible functional implications of these synaptic modifications for disease processes.

Host: Stan Froehner

May 14, 2012 

Eun Jung Hwang, PhD
California Institute of Technology
"Visuomotor control in posterior parietal cortex and implications for BMIs"

10:30am, G-328

The posterior parietal cortex (PPC) is critical for visuomotor control as evidenced by human optic ataxia in which reaching and grasping for visual objects are impaired following parietal lobe damage. Electrophysiological examinations of primate PPC have identified an area called the parietal reach region (PRR) that is specifically engaged in reach planning. Consequently, PRR has become a candidate area for reading out a subjectís reach plans for brain machine interfaces (BMIs). However, the neural circuits underlying reach plans in PRR and the viability of extracting reach plans from PRR in various BMI task conditions have not been thoroughly studied. I examined these issues in a series of experiments in the macaque PRR using multichannel extracellular recording, online decoding, and pharmacological inactivation. I found that PRR represents the intended reach goal by integrating both bottom-up visual and top-down cognitive inputs, and provides robust and adaptable signals regarding when and where to reach for BMIs. Moreover, pharmacologically disrupting the goal information in PRR causes misreaching, the hallmark of optic ataxia. I will present these findings in detail as well as a brief overview of my future research plans.

Host: Stan Froehner

May 17, 2012 

Sascha du Lac
Associate Professor, Salk Institute, Systems Neurobiology Laboratories
"Occupy Brainstem! Spikes, Synapses and Plasticity in Neurons who Work for a Living"

Host: Fred Rieke

June 05, 2012 

Elizabeth Buffalo
Assistant Professor, Emory University
"Neural Codes for Memory and Space in the Monkey Hippocampal Formation"

10:30am, G-328

While it has long been recognized that medial temporal lobe structures are important for mnemonic processing, studies in rodents have also identified exquisite spatial representations in these regions in the form of place cells in the hippocampus and grid and border cells in the entorhinal cortex. However, very little is known about potentially analogous spatial representations in the primate hippocampal formation. In this talk, I will discuss some recent experiments in which we recorded neural activity in the hippocampus and entorhinal cortex while monkeys performed free-viewing visual memory tasks. These data show that modulations in both firing rate and rhythmic neuronal synchronization are related to successful memory formation. In addition, these data provide a direct demonstration of grid cells in the primate and suggest that entorhinal neurons encode space during visual exploration, even without locomotion. These spatial representations may provide a framework to anchor the encoding of stimulus content in a complex visual scene.

Host: Stan Froehner

June 12, 2012 
Special lecture: 2012 Crill Lecture

Randy Powers
Research Professor, University of Washington
"Multiple modes of amplification in motoneurons"

4:00 PM, D-209

Host: Stan Froehner

June 14, 2012 

Ryszard Kole, PhD
Distinguished Scientist & Senior Advisor, AVI Biopharma
"Progress in Exon Skipping Therapy for Duchenne Muscular Dystrophy"

Host: Stan Froehner

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