21.01.2016: Yazan Billeh

Functional, clustered, and mesoscale brain networks

The brain is a network spanning multiple scales from subcellular to macroscopic. In this talk, I will present three projects studying brain networks at different levels of abstraction. The first involves determining a functional connectivity network based on neural spike trains and using a graph theoretical method to cluster groups of neurons into putative cell assemblies. In the second project I model neural networks at a microscopic level. Using different clustered wiring schemes, I show that almost identical spatiotemporal activity patterns can be observed demonstrating that there is broad neuro-architectural basis to attain structured spatiotemporal dynamics. Remarkably, irrespective of the precise topological mechanism, this behavior can be predicted by examining the spectral properties of the synaptic weight matrix.  Finally, I analyze axonal projections in sleep-deprived mice using data collected as part of the Allen Institute’s Mesoscopic Connectivity Atlas. I find that sleep deprivation during adolescence results in long
term reduction of overall mesoscale connectivity.