Kavli Foundation Plenary Lecture
The Kavli Foundation, based in Oxnard, California, is dedicated to the goals of advancing science for the benefit of humanity and promoting increased public understanding and support for scientists and their work. The Foundation's mission is implemented through an international program of research institutes, professorships, and symposia in the fields of astrophysics, nanoscience, neuroscience, and theoretical physics as well as prizes in the fields of astrophysics, nanoscience and neuroscience. To learn more about their foundation, please visit their website: http://www.kavlifoundation.org/
2012 Plenary Lecture
Professor, Neurobiology, Stanford University School of Medicine
Investigator, Howard Hughes Medical Institute
"A new look at gating: Selective Integration of sensory signals through network dynamics"
2011 Plenary Lecture
University Professor, Dornsife Professor of Neuroscience
Director of USC's Brain and Creativity Institute.
"About the Neural Basis of Feelings"
Abstract of Talk:
A reflection on recent advances and questions on the neuroscience of feelings,
with an emphasis on the different neural platforms required for sensing affective states.
2010 Plenary Lecture
We investigated basic neuronal reward and risk processes important for decision making using neurophysiological methods in monkeys and brain imaging in humans.
Informed decisions between different rewards are based on predictions about future outcomes. We investigated the nature of reward predictive neuronal signals in the amygdala by manipulating the informative nature of the predictive stimulus. We changed the contextual background reward while keeping stimulus reward constant. True reward predictive responses reflected the difference between background and stimulus reward, suggesting that reward contingency rather than simple stimulus-reward pairing (contiguity) determined the predictive neuronal responses.
Reward value appears to depend on the individual decision maker and the environment, and hence is subjective. Dopamine neurons in monkeys, and likely downstream striatal activations in humans, discounted reward value across temporal delays of a few seconds despite unchanged objective reward value, suggesting subjective value coding.
Reward predictions inform about probability distributions of reward values with varying degrees of risk. Subpopulations of orbitofrontal and striatal neurons, and most dopamine neurons, showed adaptation of reward related responses to the mean and variance (risk) of predicted probability distributions of reward value. These data suggest matching of distributions between neuronal output responses and reward input, resulting in effective reward coding akin to sensory adaptation. Adaptive teaching signals provide stability of learning and established performance in noisy environments. Adaptive neuronal coding may explain such behavioural phenomena as reference dependent coding.
The processing of risky outcomes depends on the subjective perception of risk and, separately, on the personal attitudes of individual decision makers towards risk. Dopamine and orbitofrontal neurons in monkeys showed distinct risk signals that were unlikely to constitute value or utility signals. In humans, risk signals and the influence of risk on value signals covaried with individual risk attitudes in subregions of prefrontal cortex, suggesting subjective coding of risk and its influence on reward value.
Taken together, these data demonstrate the nature of neuronal reward predictions and suggest subjective coding of key reward variables via temporal delays and adaptive processes in main reward structures of the brain.