1. Arboreal Mind: Finding Self in Nerve Cell Branching (Giorgio Ascoli)

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• published: 11 Jan 2011
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Part 1 of a 2-part talk. Presented by Giorgio Ascoli, Ph.D., Computational Neuroanatomy Group, Krasnow Institute for Advanced Study, George Mason University, VA The importance of neuronal morphology, i.e. the tree-like shape of nerve cells, in modern neuroscience is rooted in two foundational aspects. On the one hand, dendrites and axons mediate respectively the functional input and output of neurons. On the other, they constitute the essential substrates for network connectivity. To connect this level of scientific analysis to the philosophical problem of the mind-brain relation requires a radical shift in the current research paradigm to include first-person (subjective) experience as a legitimate topic of empirical investigation. To date, the exact neural correlates are not yet known for any conscious function. However, two general principles are commonly (if implicitly) believed. First, mental states (thoughts, feelings, memories, intentions, etc.) consist of spatio-temporal activity patterns in networks of neurons. Second, learning, meant as the acquisition of the potential to instantiate a previously unknown mental state, corresponds to the formation of new connections among neurons, enabling the activation of the new spatio-temporal pattern underlying said mental state. In this talk, Dr. Ascoli will introduce the notion that the branching structure of neurons provides a fundamental physical underpinning for a key cognitive function, namely the capability to learn. In particular, he will explain that this capability is far from trivial and that any individual can typically only acquire a fraction of the relations that can in principle be known. Moreover, he will illustrate how the spatial architecture of axons and dendrites provides a crucial constraint (and insight) on the capability to acquire knowledge. This talk will be presented at a lay level because subjective experience and tree shapes are accessible to all humankind. Dr. Ascoli is head of the Computational Neuroanatomy Group at the Krasnow Institute. The group's main effort is to model neuronal morphology (the "shape" of brain cells) and its influence on network connectivity and electrophysiological activity. One of the products of that group is L-Neuron, a modeling tool that generates and describes realistic neurons. Among the current research projects of the Computational Neuroanatomy Group are anatomically plausible neural networks and autobiographic memory. He edited the scientific book, Computational Neuroanatomy: Principles and Methods, which defines Computational Neuroanatomy in broad terms. His main long-term scientific and philosophical goal consists in establishing a working model for the highest cognitive functions such as human consciousness. His current consciousness model is fundamentally based on associative learning. On the experimental side, Dr. Ascoli's research involvement is primarily in neuroanatomy, but his scientific background is biochemistry. As a researcher at the former Laboratory of Adaptive Systems of the N.I.H., he worked on the structural characterization of a learning-associated neuronal protein, Calexcitin, and on the Prion protein, the infective agent of Mad Cow disease. He received his M.Sc. (Laurea) from the University of Pisa, and his Ph.D. from the Scuola Normale Superiore, in Italy, where he investigated drug-protein binding. The views expressed are those of the speaker and do not necessarily reflect the views of National Capital Area Skeptics.