PHYSIOLOGICAL AND COMPUTATIONAL APPROACHES TO UNDERSTANDING NEURONAL SYNCHRONIZAT

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DESCRIPTION (provided by applicant): We are interested in how high frequency (30+ Hz) brains oscillations are generated using the mouse olfactory bulb as our model system. These oscillations are a prominent feature of neural activity in many brain areas including the olfactory system. The mechanisms that underlie these oscillations, as well as the functional role they play are poorly understood, but they have recently been implicated in many aspects of brain function and disease. In the previous funding period, we have described a novel mechanism, called stochastic synchrony, by which correlated fast fluctuating inputs can generate synchronous gamma-frequency (30-80Hz) oscillations in populations of neurons. While much of our previous work used olfactory bulb neurons as a model system for analysis of this novel mechanism of synchronization, this prior work ignored many details of olfactory bulb neurons and circuits in order to describe the general features of this phenomenon. In this application we propose to extend our previous work by considering how key features of olfactory bulb circuitry and physiology modulate stochastic synchrony. We are particularly interested in whether the observed heterogeneity of neural properties is a useful feature of neural networks or is a "bug" that results from the intrinsic imprecision of biological systems. Homogeneity should enhance synchrony but recent data suggests that heterogeneity across neurons of the same type may provide certain functional advantages. We are also interested in how the synaptic connectivity of the olfactory bulb may facilitate or disrupt synchrony. Exploring these mechanisms will improve our understanding of the function and disorders of synchrony, especially in the context of the vertebrate olfactory system PUBLIC HEALTH RELEVANCE: Activity of neurons in the olfactory system represents information about sensory stimuli in the environment. One of our long term goals is to understand how to interpret features of neuronal activity as representing features of olfactory stimuli. To accomplish this goal we believe that it is critical to develop our understanding of the dynamics of neuronal activity through the use of experiments and computational models. In this proposal we describe an integrated experimental and computational approach to analysis of the mechanisms of patterns of periodic synchronized activity in the olfactory system. In particular we want to understand how the detailed and diverse biophysical and synaptic properties of olfactory bulb neurons contribute to the generation of patterned activity.