Photons and Neurons
27th Symposium: June 3-6, 2010
Supported by the National Eye Inst. R13EY020691 and the Center for Visual Science
All talks & discussion sessions were held in Goergen Hall, University of Rochester, River Campus
Thursday, June 3
7:30 - 10:30 PM Registration & Welcome Reception, Staybridge Suites (Rapids Room)
Friday, June 4
8:00 AM Registration & Breakfast, Munnerlyn Atrium
8:45 AM Welcome, Ania Majewska
Session I: Imaging Central Circuits (Krystel Huxlin, Moderator)
9:00 - 9:45 AM Eyal Seidemann, Univ. of Texas at Austin
Real-time optical imaging of neural population responses in the visual cortex of behaving monkeys: insight on population coding
What are the principles that govern the encoding and decoding of visual stimuli by populations of neurons in the primate visual cortex? To begin to address this general question, our laboratory uses a combination of voltage-sensitive dye imaging and electrophysiology to measure neural population responses from the primary visual cortex (V1) of monkeys while they perform well controlled, threshold visual tasks. To study encoding, we measure the precise spatiotemporal dynamics of V1 population responses to small visual stimuli. We then develop and test simple computational models of the early visual system that can account for the observed properties of V1 responses, and can be used as a framework for testing specific hypotheses regarding the underlying neural mechanisms. To study decoding, we develop and test possible readout models that perform the same task as the monkey using only the measured neural responses from the monkey's brain in single trials. We then compare different candidate readout models in terms of their ability to predict the visual stimulus and the behavioral choices of the monkey. In this talk, I will present some of our recent findings from these two lines of research and discuss their possible implications for population coding in the cortex.
9:45 - 10:30 AM Zachary Mainen, Champalimaud Neuroscience Programme
Reading out neural circuits for decision-making in the rat
For several years we have been studying the performance of rats in an odor mixture categorization task, in which an animal makes a left/right spatial choice instructed by the dominant component of a binary odor mixture. In order to better understand the neural basis of such odor-guided decisions we have recorded ensembles of tens of neurons in several different brain regions during the performance of this task. I will present findings from these studies, emphasizing the nature of neural representations in the primary olfactory cortex and how it is decoded or read out by downstream structures such as orbitofrontal cortex or superior colliculus.
10:30 - 11:00 AM Break (Refreshments will be served), Munnerlyn Atrium
11:00 - 11:45 AM Samuel Wang, Princeton University
Widespread shifts in activity patterns in the cerebella of locomoting mice
The cerebellum has been suggested to act as an error detector, with errors encoded by climbing fibers (CFs), which represent unexpected events, and the mossy fiber (MF) pathway, which acts as a principal source of drive to Purkinje cells, the principal output leading to the deep nuclei. This processing is context-dependent, since cerebellar responses to external events and internal signals can be modulated according to an animal's behavioral state.
To monitor the dynamics of cerebellar processing over many neurons at once, we used extracellular recording and in vivo two-photon microscopy in awake mice locomoting on a spherical treadmill. We recorded from Purkinje cell dendrites, stellate/basket interneurons, and granule cells in zone A of lobule IV/V, representing sensation and movement from trunk and limbs. In resting animals, stimuli triggered synchronous firing of dense bands of Purkinje cell dendrites and transient bursts of activity in interneurons and granule cells. The majority of granule cells showed both stimulus- and movement-related activity. The start of locomotion was marked by sustained increases in interneuron and granule cell activity followed by Purkinje cell synchrony, as well as a loss of sensitivity to external stimuli. Thus climbing fiber synchrony and mossy fiber pathways share a common upstream gating mechanism that exerts widespread control over the cerebellum.
11:45 AM - 12:30 PM Maiken Nedergaard, University of Rochester
In vivo imaging of non-neuronal brain cells
Non-neuronal cells constitute the majority of cells in CNS. Traditional electrophysiological approaches are not useful for studying electrically unexcitable cells, such as astrocytes, oligodendrocytes, NG-2 cells, and microglial cells. We have used 2-photon laser scanning microscopy in combination with photolysis (2-photon and UV) to study astrocytes and other glial cells in live, anesthetized mice. These studies are based on loading the exposed cortex with calcium indicators or imaging of endogenous fluorophores such as NADH. The advantage and limitations of 2-photon in vivo imaging will be discussed, as well as new directions used to dissect the biological functions of astrocytes.
12:30 - 1:00 PM Discussion Session
1:00 - 2:00 PM Lunch, Munnerlyn Atrium
Session II: Advances in Optical Imaging (Maiken Nedergaard, Moderator)
2:00 - 2:45 PM Eric Betzig, Janelia Farm
Pushing the envelope in biological imaging
Optical microscopy has been instrumental in studies of the structure and function of biological systems for centuries. However, many questions at the forefront of molecular, cellular, and neurobiology remain beyond its current capabilities. Here I will summarize our work in fluorescence imaging beyond the diffraction limit with photoactivated localization microscopy, deep tissue imaging with two-photon adaptive optics, and high speed volumetric cellular imaging with Bessel beam plane illumination microscopy.
2:45 - 3:30 PM Chris Xu, Cornell University
Technology development for deep tissue multiphoton imaging
MPM has been used as a standard tool for the study of blood flow, neuronal activity, and anatomy in the cortex of mouse brain. Imaging up to a depth of 600 µm for vasculature and 700 µm for neurons has been achieved with femtosecond modelocked Ti:Al2O3 oscillators. The maximum imaging depth in MPM depends on the ability of excitation light to reach the focus unscattered (ballistic excitation photons) and emitted fluorescence to reach the detector. It scales linearly with the attenuation coefficient of the excitation light in tissue and logarithmically with average power incident on the sample surface, the duty cycle, and the collection efficiency. Theer et al. achieved 1 mm imaging depth using a Ti:Al2O3 regenerative amplifier (µJ pulses) which reduces the repetition rate from 100 MHz to 200 kHz. An effective strategy for improving the imaging depth is reduction of the attenuation of excitation light by tissue. As a result of the large difference between scattering mean free paths (MFP) and absorption lengths in the brain tissue, scattering is the dominant attenuation factor over water and intrinsic molecule absorption for wavelengths between 350 nm and 1300 nm. We propose using longer excitation wavelengths, specifically the 1300-nm regime, in order to reduce the effect of scattering. In this paper, the fundamental difficulties of deep tissue imaging will be discussed. We then compare the maximal MPM imaging depth achieved with 775-nm excitation to that achieved with 1280-nm excitation using in vivo and ex vivo MPM of vasculature in the cortex of adult mouse brain. Approximately 1.15-mm imaging depth can be achieved in in vivo imaging of adult mouse brain at 1280 nm with ~ 1 nJ pulse energy. We also record blood flow speed in individual vessels at depths of up to 900 µm. Third harmonic generation imaging of red blood cell at 1280 nm excitation in in vivo mouse brain will also be presented. Practical issues and future possibilities of long wavelength MPM will be discussed.
3:30 - 4:00 PM Break (Refreshments will be served), Munnerlyn Atrium
4:00 - 4:45 PM Lihong Wang, Washington University
Photoacoustic tomography: breaking through the optical diffusion limit
We develop photoacoustic tomography (PAT) for functional and molecular imaging by physically combining optical and ultrasonic waves via energy transduction. Key applications include early-cancer detection and functional imaging. Light provides rich tissue contrast but does not penetrate biological tissue in straight paths as x-rays do. Consequently, high-resolution pure optical imaging (e.g., confocal microscopy, two-photon microscopy, and optical coherence tomography) is limited to depths within one optical transport mean free path (~1 mm in the skin). Ultrasonic imaging, on the contrary, provides good image resolution but suffers from poor contrast in early-stage tumors as well as strong speckle artifacts. PAT overcomes the above problems because ultrasonic scattering is ~1000 times weaker than optical scattering. In PAT, a pulsed laser beam illuminates the tissue and generates a small but rapid temperature rise, which causes the emission of ultrasonic waves due to thermoelastic expansion. The short-wavelength ultrasonic waves are then detected to form high-resolution tomographic images. PAT broke through the diffusion limit for penetration and achieved high-resolution images at depths up to 5 cm in tissue. Further depths can be reached by thermoacoustic tomography (TAT) using microwaves or RF waves instead of optical waves as the excitation source. PAT is commonly embodied in the forms of photoacoustic computed tomography and scanning photoacoustic microscopy.
4:45 - 5:30 PM Bart Borghuis, Janelia Farm
Dissecting rodent retinal circuits with a genetically encoded calcium indicator
The vertebrate retina is a canonical neural circuit. To dissect cell type-specific signaling in this circuit, we expressed the genetically encoded calcium indicator GCaMP3 in mouse retinal neurons. Specific combinations of transduction technique and promoter element produced different expression patterns. Using viral transduction and the human synapsin-1 promoter, GCaMP3 was expressed in ganglion cells; other retinas were incubated with the synthetic indicator OGB-1 for comparison. Light-evoked calcium responses measured in whole-mount retinas were equivalent for the two probes, both in amplitude and decay time constant. Electrophysiological recordings from GCaMP3-positive cells showed a nearly linear relation between spiking activity and fluorescence intensity. In some cells the sensor failed to signal firing rate changes below 10 spikes s-1. Sensor gain (fluorescence change per spike) varied between cells, including those of the same functional type. This precludes inferring spike rates from the fluorescence signal without additional calibration measurements. Spatio-temporal tuning functions calculated from spike and fluorescence recordings matched, and specific functional types (e.g. direction-selective) were readily detected within a population. A cell's light-evoked fluorescence response measured in dendrites was faster and larger than that measured in the soma. In ganglion cells, speed and amplitude scaled such that the integrated fluorescence signal was equal in both compartments. Using the mGluR1 promoter we measured light-evoked calcium dynamics in the soma, proximal and distal dendrites of type AII amacrine cells. These measurements agree with previous reports, support the AII's proposed connectivity and demonstrate how GCaMP3 can contribute directly to the efficient mapping of retinal circuits.
5:30 - 6:00 PM Discussion Session
6:00 - 9:00 PM Posters - Reception/Dinner, Munnerlyn Atrium
Saturday, June 5
8:00 AM Breakfast, Munnerlyn Atrium
Session III: Imaging the Senses (David Williams, Moderator)
9:00 - 9:45 AM Tim Holy, Washington University
Outnumbered no more: deciphering olfactory coding using fast three-dimensional calcium imaging
Mammals detect chemical cues in their environment using their sense of smell. The great diversity of volatile compounds is matched by a great diversity of the detectors: more than a thousand different receptors, 3-4% of the mammalian genome, are expressed olfactory sensory neurons, with each neuron expressing just one receptor. This diversity poses a challenge to physiological studies that seek to understand the function of the olfactory system.
Recently, we have developed techniques for fast three-dimensional imaging using light sheets. In conjunction with mice expressing the genetically-encoded fluorescent calcium sensor GCaMP2, we record olfactory responses from thousands of sensory neurons simultaneously. These recordings have revealed, in fine detail, numerous (and previously-unexpected) patterns in sensory responses across neurons.
We are also improving the technology for fast imaging, in particular increasing both the temporal and spatial resolution of volumetric calcium imaging.
9:45 - 10:30 AM Austin Roorda, UC Berkeley
Exploring vision in living eyes on a cellular scale
Challenges in understanding the limits to vision are imposed by the eye's optical aberrations and eye movements. Both are large relative to the size of cones and receptive fields at and near the fovea. Systems that combine adaptive optics (AO) with eye tracking offer unique ways to reveal some of the basic properties and limits of vision. We use an AO scanning laser ophthalmoscope to project stimuli onto the retina while simultaneously imaging its microscopic structure at video rates. In human studies, we find that immediately outside of the foveal center, spatial vision degrades faster than predicted by cone photoreceptor spacing, suggesting that ganglion cell receptive field centers near the fovea may comprise more than one cone. We've confirmed the existence of larger-than-expected receptive field centers near the fovea through targeted cone stimulation and simultaneous electrophysiological recording to map the cones that comprise receptive fields in the macaque.
Our efforts to track the retina and control the retinal stimulus continually reinforce the notion that spatial percepts derive from both spatial and temporal processes. We measured the conditions under which retinal stimulus motion is perceived as being stable, and discovered that only retinal image motions that are consistent with the retinal slip generated by normal eye motion are seen as stable, whereas retinal image motions that are inconsistent with the eye's motion, even at very small magnitudes, appear unstable.
10:30 - 11:00 AM Break (Refreshments will be served), Munnerlyn Atrium
11:00 - 11:45 AM Donald Miller, Indiana University
Probing photoreceptor activity using adaptive optics and optical coherence tomography
Vision begins with the capture of light by photoreceptors, triggering a complex cascade of biochemical events called phototransduction that culminates in the hyper-polarization of the photoreceptors. Phototransduction has been extensively studied in vitro, however, direct observation in the living eye has been confined to the initial photon absorption kinetics (measured by photopigment densitometry) and the final membrane hyper-polarization (measured by electrophysiology) event. While the cascade of activation and amplification stages can be probed using electrophysiological techniques such as double flash, the analysis is somewhat indirect, and a more direct and local measurement would be useful. To this end we have developed a non-invasive optical technique based on high speed imaging and adaptive optics to observe in individual cones the fast physiological processes that accompany phototransduction. The method takes advantage of the interference of multiple reflections within the outers segments (OS) of cones, a self-interference phenomenon that is highly sensitive to phase changes caused by variations in refractive index and physical length. The same self-interference phenomenon can also be used to measure the rate of outer segment renewal, a gradual lengthening (2-3 microns/day) of the OS necessitated by the extreme optical and metabolic demands of phototransduction. To our knowledge these are the first demonstrations of in vivo optical imaging of the fast physiological processes that accompany phototransduction and the extremely slow process of OS renewal in individual photoreceptors. Results of these measurement and efforts to expand them to 3D using optical coherence tomography are discussed.
11:45 AM - 12:30 PM Joseph Carroll, Medical College of Wisconsin
Imaging the human retina - development & disruption
High-resolution ophthalmic imaging techniques like optical coherence tomography and adaptive optics ophthalmoscopy have literally changed the way we see the retina. Pathology can now be assessed on the cellular level, and numerous sub-clinical phenotypes have been uncovered. This talk will discuss on the use of these imaging modalities to provide insight into foveal development, both using the normal retina and cases where development has been disrupted (albinism). We are beginning to appreciate the role of pigmentation in foveal development, and this understanding offers the possibility that we may be able to modify foveal anatomy through modifying pigment production in the retina.
I will also discuss recent advances in our understanding of color vision defects. We have assembled a collection of individuals with various genetic mutations that all result in some type of cone dysfunction. Given the involvement of a single genetic locus, we have begun to construct a high-resolution genotype-phenotype map for these conditions. As a result, our understanding of the etiology of some of these conditions has improved - a requisite first step for identifying therapeutic opportunities for individuals with these disorders.
12:30 - 1:00 PM Discussion Session
1:00 - 2:00 PM Lunch, Munnerlyn Atrium
Session IV: Imaging Visual Cortical Circuits (Ania Majewska, Moderator)
2:00 - 2:45 PM Rafael Yuste, Columbia University
Two-photon mapping and manipulation of neocortical circuits
We have developed optical methods to stimulate or inhibit individual neurons in brain slices in any arbitrary spatio-temporal pattern, using two-photon uncaging of RuBi-glutamate or RuBi-GABA with beam multiplexing with DOEs or SLMs. By sequentially stimulating up to a thousand potential presynaptic neurons, we generate functional maps of inputs to a cell. In addition, we combine this approach with two-photon calcium imaging in an all-optical method to image and manipulate circuit activity.
2:45 - 3:30 PM David Fitzpatrick, Duke University
Imaging the experience-dependent emergence of functional circuits in visual cortex
The onset of vision occurs when neural circuits in the visual cortex are immature, lacking both the full complement of connections, and the response selectivity that defines functional maturity. The direction-selective responses of cortical neurons are particularly vulnerable to the effects of early visual deprivation, but it remains unclear how stimulus-driven neural activity guides the emergence of cortical direction selectivity. We developed a novel motion training paradigm that allows us to monitor the impact of visual experience on the developmental emergence of direction selective response properties in individual visually naïve ferrets. Using intrinsic signal imaging techniques, we found that training with a single axis of motion induced the rapid emergence of direction columns that were confined to cortical regions preferentially activated by the training stimulus. To probe alterations in the response properties of single cells that underlie the emergence of direction columns, we used in vivo two-photon imaging following injections of the calcium indicator Oregon Green BAPTA. In visually naive animals, single neurons exhibited strong selectivity for orientation, but only weak directional biases and they lacked the strong local coherence in the spatial organization of direction preference that was evident in mature animals. Training with a bidirectional moving stimulus rapidly strengthened the direction-selective responses of individual neurons by building on the weak initial biases and producing a significant increase in local coherence. Dark rearing experiments showed that the weak initial biases are dependent on visual experience and are essential for the rapid emergence of direction selective responses. Additional evidence that experience with stimulus motion plays an instructive role in this process comes from the fact that unidirectional training results in a preponderance of neurons that prefer the direction of the training stimulus, and that changes in direction selectivity are absent when animals are trained with a flashing grating stimulus. We conclude that early experience with moving visual stimuli drives the rapid emergence of direction-selective responses in the visual cortex.
3:30 - 4:00 PM Break (Refreshments will be served), Munnerlyn Atrium
4:00 PM - 4:45 PM Anna Roe, Vanderbilt University
Imaging attention in the brain: optical imaging studies of area V4 in awake, behaving macaque monkeys
Area V4 in the macaque monkey is a mid-tier cortical area in the ventral visual pathway. It plays important roles in visual object recognition and in visual attention. Neurons in V4 are tuned for orientation, spatial frequency, and color, as well as complex properties such as curvature, color constancy, and figure-ground response. Neuronal responses in V4 are also markedly modulated by spatial and featural attention. However, little is known regarding the functional organization of area V4 and how attention may relate to such functional organization. We used intrinsic signal optical imaging methods to map foveal and perifoveal regions of V4 in monkeys performing visual fixation, spatial attention, or featural attention tasks. Our studies reveal the presence of submillimeter-sized functional domains in V4 that exhibit preferential response to color, luminance, or orientation. In monkeys trained on attention tasks, we find spatial attention leads to topographically appropriate enhancement of imaged response which is not selective for domain type. In contrast, feature attention leads to little modulation of signal amplitude but significant enhancement of response correlation between feature domains relevant to the attended feature. Our data thus suggest that spatial and feature attention may be mediated in V4 in substantially different ways, one by modulation of response amplitude and the other by domain-specific response correlation. This also suggests that different attentional modes mediate their effect by recruiting different networks of functional domains in V4. These findings are consistent with and lend an organizational understanding to a large body of electrophysiological data. As well, they raise interesting questions with respect to the role of prefrontal influences on functional domain response in V4, a topic which awaits future study.
4:45 - 5:30 PM Mark Hübener, Max Planck Institute, Martinsried
Structural plasticity of excitatory and inhibitory neurons in mouse visual cortex
We are interested in changes in neuronal circuitry underlying plasticity in the visual cortex. As one means to induce plasticity in mouse visual cortex we use monocular deprivation (MD). Functional imaging revealed a savings effect in this system: the shift in eye representation occurs faster in mice that have already experienced an MD episode many weeks earlier. In order to study the potential synaptic mechanisms underlying this savings effect, we monitored GFP expressing pyramidal neurons with two-photon imaging. MD increased the number of dendritic spines in a cell type specific fashion, possibly reflecting the strengthening of open eye inputs. Surprisingly, the added spines did not disappear after reopening the temporary closed eye. In contrast, the induction of a second MD of the same eye many weeks later did not lead to further addition of spines, but spines induced by the first MD increased in size, indicating their functional reactivation, and suggesting that these persisting spines might form a structural trace mediating the savings effect.
Using a different paradigm, we studied the structural plasticity of GFP expressing inhibitory neurons. Following a complete loss of visual input by lesioning the retina, we did not detect any obvious changes in the overall dendritic structure of these neurons. Upon closer examination, we found that a subset of the labeled inhibitory cells had dendritic spines, as had been previously described for certain types of inhibitory neurons. Within 48 hours of lesioning the retina, more than 25% of these spines were permanently lost. In order to determine if the degree of spine loss depends on the level of cortical activity, we used a focal retinal lesion paradigm, thus creating a silenced region in the visual cortex, the lesion projection zone (LPZ), which is surrounded by a gradient of visually evoked activity. We found spine density to be correlated with distance from the border of the LPZ, such that cells located nearest to the LPZ had densities similar to those inside, while cells located far from the LPZ had densities comparable to controls. These results show that, similar to excitatory cells, inhibitory neurons are capable of rapid remodeling of synaptic input structures following alterations of neuronal activity.
5:30 - 6:00 PM Discussion Session
6:00 - 7:00 PM Posters
7:30 - 9:30 PM Dinner, George Eastman House
Sunday, June 6
8:00 AM Breakfast, Munnerlyn Atrium
Session V: Controlling Neurons with Light (Tony Movshon, Moderator)
9:00 - 9:45 AM Richard Kramer, UC Berkeley
Non-genetic photochemical tools for controlling neural activity with light
Light-regulated ion channels have opened new horizons for the optical control of neural activity. Genetic engineering enables photosensitization of specific neurons with light-regulated channels either borrowed from microbes or invented by chemical-biologists. Here I will discuss an alternative approach to imparting light-sensitivity, which involves the modification of endogenous ion channels in neurons by acute application of a small molecule "photoswitch." AAQ is a photoswitch that bestows light-sensitivity onto many voltage-gated K+ channels, without genetic modification. We have used AAQ to confer light-sensitivity onto retinas from blind rd1 mice, whose rods and cones degenerate after birth, leaving the rest of the retina intact but unable to respond to light. Brief application of AAQ bestows prolonged light sensitivity on multiple types of retinal neurons, resulting in synaptically amplified responses in retinal ganglion cells. Intraocular injection of AAQ can restore the pupillary light reflex, indicating restoration of signaling through brain circuits. Another photoswitch, named QAQ, shows promise as a light-regulated analgesic. The trans configuration QAQ is an intracellular blocker of every voltage-gated ion channel tested (K+, Na+, and Ca2+ channels), but blockade is alleviated by switching to cis with 380 nm light and restored by switching to trans with 500 nm light. The net effect is that neuronal activity can be silenced in a light-reversible manner. QAQ can be delivered into cells through ion channels with dilating pores, including the "capsaicin receptor" (TRPV1) and the ionotropic receptor for ATP (P2X). TRPV1 channels and P2X receptors are expressed in pain-sensing neurons. Hence co-application of QAQ plus capsaicin or ATP enables optical control of spiking in a targeted neuronal population without requiring exogenous gene expression. By enabling precise photoregulation, QAQ will facilitate scientific investigation of pain mechanisms and could have clinical use as an analgesic that is much more rapidly reversible than currently available drugs.
9:45 - 10:30 AM Ed Boyden, MIT
Controlling brain circuits with light: enabling integrative analysis and engineering of neural systems
Over the last several years our group has developed a suite of genetically-encoded reagents that enable powerful neural activation and silencing in response to pulses of light of specific colors. We discuss a new generation of such reagents that we have developed, with enhanced power and flexibility. In order to enable these tools to be used for systematic analysis of the causal contribution of specific cell types, pathways, and brain regions to neural computations, behaviors, and pathologies, we have developed hardware to enable neural circuits to be perturbed in a three-dimensional fashion, and for the network-wide impact of a circuit perturbation to be characterized. We explore how these tools can be used to enable systematic analysis of neural circuit functions, exploring the properties of neural circuits that mediate emotion and sensation, and that play roles in neurological and psychiatric disorders. We also discuss the translational potential of such tools to potentially enable novel ultraprecise neuromodulation therapies, resulting from our recent assessment of the safety and efficacy of optical neural control tools in the non-human primate brain.
10:30 - 11:00 AM Discussion Session
11:00 - 11:45 AM Break (Refreshments will be served), Munnerlyn Atrium
11:45 AM - 12:30 PM Jeff Lichtman, Harvard University
Connectomics in the developing nervous system
Connectional maps of the brain may have value in developing models of both how the brain works and how it fails when subsets of neurons or synapses are missing or misconnected. Such maps might also provide the first detailed information about how brain circuits develop and age. I am especially eager to obtain such maps from the developing nervous system because of a longstanding interest in the neuromuscular circuit changes during mammalian early postnatal life. In the neuromuscular system most axonal input to muscle fibers is pruned in early postnatal life. This so called 'synapse elimination' may be part of the process whereby the nervous system molds itself to a particular epigenetic landscape. We have developed techniques to observe all these synaptic interactions at different sites simultaneously by computer assisted axonal tracing and the generation of transgenic mice in which different axons are labeled different colors. These Brainbow mice (Livet et al., 2007) have given us an opportunity to see the entire connectional maps (or 'connectomes') for developing muscles. In brain, however, thin sectioning is required to disambiguate the many overlapping axons. My colleagues Ken Hayworth and N. Bobby Kasthuri have developed a new kind of microtome (and an electron imaging strategy) that allows automated high resolution imaging of thousands of ultra thin (<30 nm) sections that are very large (~4 mm2). This approach aims at making large scale serial microscopic analysis of volumes routine.
12:30 - 1:00 PM Wrap-up Discussion Session, Tony Movshon
1:00 - 1:15 PM Closing Remarks
End of Meeting
1:45 PM Barbecue at the home of David & Inger Williams, Fairport, NY
Ania Majewska, University of Rochester
David Williams, University of Rochester
Tony Movshon, New York University