The Bernstein Center Freiburg

Informal Seminar
Thomas Petermann

ETH Zurich

The role of local interconnectedness in probablistic processes

Neuronal avalanches in vivo and their threshold invariance
Friday, April 9, 2010
14:30 h sharp
Bernstein Center
Hansastr. 9a
Part I: While the influence of small global distances in probablistic processes has been noted, it remains a great challenge to find approaches that unravel the precise role of local interconnectedness. Such topological properties enter very naturally in the framework of our two-time-step description, and it provides a quantitative interpretation of the role of loops up to length 4 in the stationary behavior.

Part II: Spontaneous neuronal network activity is an important property of the cerebral cortex but its spatiotemporal organization remains poorly understood. Here we show that negative LFP deflections (nLFPs), indicative of cortical synchronization, in awake rhesus monkeys form neuronal avalanches that are scale-invariant in space, time and with respect to the threshold of nLFP detection. This dimension, threshold invariance, describes a fractal organization: smaller nLFPs are embedded in clusters of larger ones without destroying the spatial and temporal scale-invariance of the dynamics.
The talk is open to the public. Guests are cordially invited!