Phase Transitions in Brain
Networks
Phase
transitions occur in a variety of physical and biological systems, including
brain networks. They are characterized by instabilities that generate special dynamical
properties, which are associated with dynamical and functional benefits. Phase
transition is also an appealing framework that has been utilised to explain
pathological brain activity. Historically, the idea of phase transitions in the
brain is not new and has sparked some controversy over the years. In this half-day
workshop, a number of current world-class experts will revisit the possible
roles of phase transitions in the brain. They will discuss the recent progress
in the field and the relevance and limitations of this framework to
computational neuroscience. In order to further exploit and explicitize
contemporary viewpoints on the promises and pitfalls of phase transitions in
the brain, we will end this workshop with a roundtable discussion in which the
speakers and the audience will be invited to participate. When: July 16. Where: Barcelona. Speakers: • Anna Levina (MPI): Influence of spatial structure on data processing and phase transitions in neuronal networks • Serena di Santo (Universidad de Granada): Building a Landau-Ginzburg theory of the brain • Jonathan Touboul (Brandeis University): The statistical mechanics of noise-induced phase transitions • Fernando Santos (UFPE): Topological phase transitions in functional brain networks • James Roberts (QIMRB): Geometry and fragility of the human connectome • Linda Douw (Amsterdam UMC): A historical perspective on phase transitions in the brain Abstracts Anna Levina (MPI) Influence of spatial structure on data processing and phase transitions in neuronal networks Networks are backbones of the complex brain activity. Modern methods allow extracting more and more reliable functional and structural networks on different scales. One of the major challenges is to understand the relationship between the structure of the network and the properties of its dynamics. Using simple models and data analysis I am going to discuss, on the one hand, how the features of the networks are reflected in the dynamics of single units. And on the other hand, how the system's structure changes the nature of the phase transition in its dynamics. Serena di Santo (Universidad de Granada) Building a Landau-Ginzburg theory of the brain Jonathan Touboul (Brandeis University) The statistical mechanics of noise-induced phase transitions Fernando Santos (UFPE) Topological phase transitions in functional brain networks James Roberts (QIMRB) Geometry and fragility of the human connectome The human connectome is a topologically complex, spatially embedded network. While its topological properties have been richly characterized, the constraints imposed by its spatial embedding are poorly understood. In this talk I will present a recent novel resampling method that enables randomization of a network while preserving its spatial embedding. Applying this method to tractography data reveals that the brain's spatial embedding – its geometry – makes a major contribution to the topology of the human connectome. For example, geometry accounts for much of the brain's modularity. But geometry is not the sole determinant: the brain's structural hubs would be positioned closer to the geometric center of the brain if geometry was the only source of topology. Closer analysis of the brain's hubs under weaker randomization reveals that the brain sits at a local minimum in wiring cost, and that progressive randomization leads to a topologically unstable regime consistent with a phase transition. Moreover, prefrontal hubs are particularly fragile to perturbations, correlating with the pattern of acceleration of grey matter loss in schizophrenia. This suggests that fragile prefrontal hub connections and topological volatility act as evolutionary influences on complex brain networks, whose set point may be perturbed in neurological and psychiatric disorders. Linda Douw (Amsterdam UMC) A historical perspective on phase transitions in the brain Organizers: Leonardo Gollo (QIMRB) Linda Douw (Amsterdam UMC) Past events: |
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