2012 Kavli Prize in Astrophysics: David Jewitt, Jane Luu and Michael Brown
"for discovering and characterizing the Kuiper Belt and its largest members, work that led to a major advance in the understanding of the history of our planetary system."
In 1992, the Solar System became a much larger and more interesting place. That’s when astronomers David Jewitt and Jane Luu discovered the first of many dozens of objects at the frigid and dark edge of the solar system – celestial bodies that collectively would be known as the Kuiper Belt. Later, Michael Brown made startling discoveries of increasingly larger Kuiper Belt Objects, including one he called Eris that is more massive than Pluto, and another beyond the Kuiper Belt he called Sedna. These and other discoveries forced astronomers and the larger public to re-think not only the overall architecture of the solar system but the very status of Pluto so that now the solar system has only eight planets.
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2012 Kavli Prize in Nanoscience: Mildred Dresselhaus
“for her pioneering contributions to the study of phonons, electron-phonon interactions, and thermal transport in nanostructures.”
Mildred Dresselhaus, the first sole recipient of a Kavli Prize, has had a long and illustrious career in physics. Dubbed "The Queen of Carbon" by her peers, she was instrumental in unlocking the secrets of carbon's electronic structure and the mysterious forms it takes on in nature. Among her accomplishments, Mildred Dresselhaus contributed to the discovery of fullerenes – very large molecules of carbon that resemble Buckminster Fuller’s geodesic domes. She also predicted the existence of carbon nanotubes – single-atom-thick cylinders of carbon that could be used in everything from stronger materials, ultrastrong cables, and hydrogen storage to advanced electronics, solar cells, and batteries. And she remains a leader in the science of nanoscale carbon structures, which are thousands of times smaller than the diameter of a human hair, exploring their electronic behavior and how they convert heat into electricity.
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2012 Kavli Prize in Neuroscience: Cori Bargmann, Winfried Denk and Ann Graybiel
“for elucidating basic neuronal mechanisms underlying perception and decision"
Understanding how the brain receives information from the environment and processes it to make decisions is a major challenge in neuroscience. Cori Bergmann, Winfried Denk and Ann Graybiel have addressed this question in different organisms. Bargmann used nematode worms to gain insight into the molecular controls for animal behaviour; Denk developed techniques that allowed him to answer major questions about how information is transmitted from the eye to the brain; Graybiel identified and traced neural loops going from the outer layer of the brain to a region called the striatum and back again, and revealed that these form the basis for linking sensory cues to actions involved in habitual behaviours.
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How do genes and the environment interact to generate a variety of behaviors? How are behavioral decisions modified by context and experience? Genetic variation, internal states, and environmental cues converge on shared neuronal circuits to regulate behaviors in the nematode worm Caenorhabditis elegans. An anatomical wiring diagram provides an essential map for innate behaviors, such as preferences for specific odors. Superimposed on this detailed circuit diagram are neuromodulators reflecting internal states, which help select appropriate behavioral responses from a larger number of latent circuits. Individual genetic variation and experience change an animal's sensitivity to external and internal regulators, generating behavioral diversity. Return to Top
The past decade saw an explosion in the discoveries of Pluto- and near Pluto-sized bodies in the outer solar system, giving rise to a new classification of "dwarf planets." Like Pluto, each of these largest dwarf planets has a unique story to tell about the history and evolution of the solar system. I'll discuss the discoveries of these objects and the new views of giant collisions, stellar encounters, and planetary rearrangement that we are gaining from their study. Return to Top
Both, generating and testing ideas of how the nervous system works have always relied heavily on microscopes and the images they generate. No tissue is more defined by the pattern of connections between cells and nowhere is imaging functional signals from intact, living tissue and mapping its structure with high resolution and wide scope more important. Two-photon-excitation fluorescence microscopy allows the former, serial block-face electron microscopy the latter. Combining both on the same piece of retinal tissue, we showed how specific the neural connectivity is in the direction-selectivity circuit. We also performed a dense, almost complete, reconstruction of the inner-plexiform-layer in a piece of retina. This allowed the determination of a connection matrix (connectome), whose functional implications are currently analyzed. The availability of the axonal and dendritic morphologies of all bipolar cells in this volume allowed the exhaustive classification of bipolar-cell types, which yielded a new, rare type of bipolar cell. Using their connectivity to the ganglion cells we could also sub-classify the "type 5" bipolar cell. A future goal is to extend serial block-face EM to the whole mouse brain. Return to Top
Nanoscience is strongly influenced by the physical properties of nanostructures, which are highly sensitive to the behavior of the interactions between electrons, phonons which denote the lattice vibrations of the constituent atoms, and the interaction between these electrons and phonons known as the electron-phonon interaction. Whereas the electrical conductivity of materials can vary between one material and another by many orders of magnitude, the thermal conductivity varies by only a few orders of magnitude. This talk will discuss how nanostructures can be used to vary and control the electrical and thermal properties of materials, both for enhancing and suppressing such properties as the electrical and thermal conductivities. Some insight will be given into how and why this enhancement and suppression occurs, how we study the novel phenomena occurring at the nanoscale, and why the science community is excited about advances that have been made in the past 20 years, including some contributions made in my research group. Return to Top
Until quite recently, our view of how the brain represents thought and action mainly emphasized neural circuits in the cerebral cortex. Paradoxically, however, major inputs to the neocortex come from deeply buried brain regions long thought to be primitive in nature. This lecture will focus on this paradoxical brain architecture and how it relates to the transitions that we make between conscious, deliberative behavior and habitual, semi-automatic behavior. When we act out of "habit", we can perform sequences of behavior that initially are clearly directed by value-monitoring functions of the brain; but in other instances, our behaviors seem to occur regardless of the positive or negative value of the behaviors. Experimental findings now suggest that cortico-basal ganglia circuits operate to build new patterns of activity as positive and negative expected outcome values are learned, and as transitions occur between clearly value-driven behaviors and semi-automatic behaviors. Strikingly, these neural circuits can be quite flexible or quite fixed in their signaling properties. With the development of new methods, the dynamics of cortico-basal ganglia circuits can be probed along with the monitoring of behavior and neural activity. These combinations of methods are yielding a new view of the transitions in neural activity that allow us to shift between behavioral flexibility and behavioral fixity. They also are yielding new views of emotional decision-making. It is likely that many of these changes reflect epigenetic as well as genetic modulation of circuits interconnecting elements in extended cortico-basal ganglia circuits. Remarkably, the same circuits that operate in the transition from deliberative to habitual behavior are implicated in a range of neurologic and neuropsychiatric disorders. Our goal is to uncover mechanisms of action of cortico-basal ganglia circuits that will yield critical insights into these disorders and the potential for their treatment. Return to Top
Previously unknown and unexplored, the trans-Neptunian region is the Solar System's deep freeze - an icy repository of the most primitive objects in the Solar System. The scientific impact of the Kuiper belt on the study of the formation and evolution of the Solar System cannot be overstated. The Kuiper belt is the source of the short-period comets and a relic of the formation epoch 4.6 billion years ago. Evidence from the distribution of Kuiper belt objects proves that the planets did not form in their present orbits, a result with deep implications for the history of our system. The belt is also a local analogue of dusty disks recently discovered around nearby main-sequence stars, so connecting the planetary and stellar astronomy communities. I will provide a sweeping and accessible big-picture overview of Kuiper belt science. Return to Top
Up until the 1990's, many astronomers thought we knew everything that was in the solar system: the planets and their satellites, the asteroids, the meteorites, the comets. In fact, if one talked to the average astronomer, chances were he/she would have asked what was left to study in the solar system. Was not everything known already? This perception of the solar system was turned upside down in 1992, when our survey of the outer solar system revealed that the region beyond the planets was full of things, moving in orbits no one had expected. I will recount the story of our exploration of the outer solar system. Return to Top