Balancing on an edge: dynamical criticality as a biological strategy for flexibility and integration
Monday, September 28, 2015 - 12:00pm to 1:00pm
Joseph Henry Room, Jadwin Hall
Physics and the Lewis-Sigler Institute

A number of biological systems organize themselves so as to be perpetually at the fulcrum between large, opposing forces. Simultaneously rapid synthesis and degradation of mRNA or proteins, ion channels open while ion pumps go at full blast, muscle tone of both muscles and countermuscles pulling our limbs in opposite directions, and large amounts of simultaneous excitatory and inhibitory activity in cortex: all these are well-established examples of this strategy. Like running the air conditioning and the heating at full blast at the same time, this strategy appears wasteful, since it continuously consumes energy, but what does it in fact achieve?

The precarious balance at the center of such tug-of-wars is called a critical point. It has been well-established that such a critical point underlies amplification and frequency selectivity in the cochlea. I will describe models of cortical dynamics where various critical poising scenarios balancing excitation and inhibition allow for the creation of flexible, rapidly changing states, and for adaptive strategies that can vary temporal or spatial scales of sensory integration depending on the signal-to-noise level of the input. I shall finally review analysis of ecocorticography recordings in humans and primates, showing that critical dynamics features present during awake behaviour disappear during induction of sleep and anesthesia.

View profile of Marcelo Magnasco.