Cambridge-based researchers provide new evidence that the human brain lives "on the edge of chaos", at a critical transition point between randomness and order. The study, published March 20 in the open-access journal PLoS Computational Biology, provides experimental data on an idea previously fraught with theoretical speculation.
Self-organized criticality (where systems spontaneously organize themselves to operate at a critical point between order and randomness), can emerge from complex interactions in many different physical systems, including avalanches, forest fires, earthquakes, and heartbeat rhythms. According to this study, conducted by a team from the University of Cambridge, the Medical Research Council Cognition & Brain Sciences Unit, and the GlaxoSmithKline Clinical Unit Cambridge, the dynamics of human brain networks have something important in common with some superficially very different systems in nature. Computational networks showing these characteristics have also been shown to have optimal memory (data storage) and information-processing capacity. In particular, critical systems are able to respond very rapidly and extensively to minor changes in their inputs.
"Due to these characteristics, self-organized criticality is intuitively attractive as a model for brain functions such as perception and action, because it would allow us to switch quickly between mental states in order to respond to changing environmental conditions," says co-author Manfred Kitzbichler.
The researchers used state-of-the-art brain imaging techniques to measure dynamic changes in the synchronization of activity between different regions of the functional network in the human brain. Their results suggest that the brain operates in a self-organized critical state. To support this conclusion, they also investigated the synchronization of activity in computational models, and demonstrated that the dynamic profile they had found in the brain was exactly reflected in the models. Collectively, these results amount to strong evidence in favour of the idea that human brain dynamics exist at a critical point on the edge of chaos.
According to Kitzbichler, this new evidence is only a starting point. "A natural next question we plan to address in future research will be: How do measures of critical dynamics relate to cognitive performance or neuropsychiatric disorders and their treatments?"
PLEASE ADD THIS LINK TO THE PUBLISHED ARTICLE IN ONLINE VERSIONS OF YOUR REPORT: http://dx.plos.org/10.1371/journal.pcbi.1000314 (link will go live upon embargo lift)
CITATION: Kitzbichler MG, Smith ML, Christensen SR, Bullmore E (2009) Broadband Criticality of Human Brain Network Synchronization. PLoS Comput Biol 5(3): e1000314. doi:10.1371/journal.pcbi.1000314
Dr. Ed Bullmore
University of Cambridge
This press release refers to an upcoming article in PLoS Computational Biology. The release is provided by the article authors and/or their institutions. Any opinions expressed in this release or article are the personal views of the journal staff and/or article contributors, and do not necessarily represent the views or policies of PLoS. PLoS expressly disclaims any and all warranties and liability in connection with the information found in the releases and articles and your use of such information.
About PLoS Computational Biology
PLoS Computational Biology (www.ploscompbiol.org) features works of exceptional significance that further our understanding of living systems at all scales through the application of computational methods. All works published in PLoS Computational Biology are open access. Everything is immediately available subject only to the condition that the original authorship and source are properly attributed. Copyright is retained by the authors. The Public Library of Science uses the Creative Commons Attribution License.
About the Public Library of Science
The Public Library of Science (PLoS) is a non-profit organization of scientists and physicians committed to making the world's scientific and medical literature a freely available public resource. For more information, visit http://www.plos.org.
PLEASE MENTION THE OPEN ACCESS JOURNAL PLoS COMPUTATIONAL BIOLOGY (www.ploscompbiol.org) AS THE SOURCE FOR THIS ARTICLE AND PROVIDE A LINK TO THE FREELY AVAILABLE TEXT. THANK YOU.
PLoS Computational Biology is an open-access, peer-reviewed journal published weekly by the Public Library of Science (PLoS) as the official journal of the International Society for Computational Biology (ISCB).
PLoS Computational Biology