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BEGIN:VEVENT
DTSTAMP:20260921T114417Z
LAST-MODIFIED:20180611T123112Z
DTSTART:20180611T170000Z
DTEND:20180611T180000Z
UID:event1953@bu.edu
URL:http://physics.bu.edu/internal/events/show/1953
SUMMARY:Critical Dynamics and Self-organization in Bursts of Brain Rhythms 
	as a Fundamental Hallmark of Physiological Function
DESCRIPTION:Featuring Jilin Wang\n\nPart of the Preliminary Oral Exam.\n\nE
	xamining Committee:  Plamen Ivanov\, Karl Ludwig\, Shyam Erramilli\, Kirill
	 Korolev\n\nAbstract: In nature\, systems consisting of many interacting co
	nstituents may organize themselves into a state characteristic of equilibri
	um systems at the critical point\, without any significant external "tuning
	". The dynamics of such systems is characterized by long-range spatio-tempo
	ral correlations\, and the statistical properties are described by power-la
	ws. Following Bak\, Tang and Wiesenfeld\, this behavior is described as sel
	f-organized criticality (SOC).\nIn the mammalian brain\, neuronal networks 
	exhibit bursting dynamics\, with a complex temporal organization that invol
	ves rhythms covering a broad range of frequencies. Rhythms in different fre
	quency bands often occur in bursts that last from seconds to minutes\, and 
	are one of the most important features of brain activity throughout the ent
	ire sleep-wake cycle.\nEarlier studies have reported that the micro-structu
	re of wake and sleep episodes shows a SOC-like dynamics. Based on these ear
	lier observations\, we initiated investigations of the bursting dynamics of
	 θ and δ rhythms\, which are typically associated with sleep. We found th
	at bursts of θ rhythms exhibit a temporal organization characterized by a 
	power-law probability distribution for their durations and long-range power
	-law correlations. In contrast\, δ-burst durations follow a Weibull distri
	bution\, rather than a power-law. These distinct behaviors of θ- and δ-bu
	rsts are reminiscent of the ‘avalanche’ and waiting time dynamics in ot
	her out-of-equilibrium physical systems exhibiting SOC\, and in their corre
	sponding models. We find that the duality of power-law vs Weibull and the a
	ssociated scaling properties are robust features of brain dynamics across t
	he sleep-wake cycle. Moreover\, in addition to the long-range power-law tem
	poral correlations in the bursting dynamics of θ and δ-bursts\, we uncove
	r a robust coupling between the durations of consecutive θ and δ bursts. 
	The discovered non-equilibrium features in brain dynamics fall outside the 
	current paradigm of sleep as a system in equilibrium (homeostasis)\, are no
	t addressed by current empirical and modeling investigations\, and open new
	 avenues to understanding brain dynamics and functions under healthy condit
	ions and pathological perturbations.
LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215
STATUS:CONFIRMED
CLASS:PUBLIC
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