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W. G. Pritchard Lab Seminar: 11:15 AM - 12:15 PM, 106 McAllister Bldg

	              **Monday November 6, 2006**
	
Spatiotemporal pattern formation and control in the brain

Steven J. Schiff

Depts Neurosurgery / Engineering Science & Mechanics
Penn State University


Abstract:

Although the identification of oscillatory dynamics following stimulation 
of the sensory sheets of mammalian cortex has been long established, the 
spatiotemporal organization of such oscillations have not been well 
studied. We here describe the dynamical organization and evolution of 
oscillatory pattern formation in tangential slices of the middle cortical 
layers of rat visual cortex using voltage sensitive dyes. These episodes 
follow a pattern of spatiotemporal irregular and high dimensional 
activity, which spontaneously organize into spiral, plane, and ring waves, 
followed by gradual dissolution into irregular wave activity prior to 
episode termination. We demonstrate using a principal orthogonal 
decomposition that these dynamics evolve within a phase space whose 
dimensions shrink and expand consistently regardless of the specific wave 
type observed, and that this consistency is reflected in both amplitude as 
well as the frequency domain. We speculate that such empirical mode 
decomposition reveals the basic building blocks of cortical dynamics. We 
furthermore speculate on experimentally testable control strategies.

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