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SUMMARY:The cognitive relevance of the community structure of the function
 al co-activation network of the human brain - Nicolas Crossley\, Institute
  of Psychiatry\, King's College London
DTSTART:20121204T110000Z
DTEND:20121204T120000Z
UID:TALK41489@talks.cam.ac.uk
CONTACT:Mikail Rubinov
DESCRIPTION:There has been growing interest in the complex topology of hum
 an brain functional networks\, often measured using resting state function
 al MRI (fMRI). Here\, we used a meta-analysis of the large primary literat
 ure that employed fMRI or PET to measure task-related activation (>1600 st
 udies\; 1985-2010). We estimated the similarity (Jaccard index) of the act
 ivation patterns across experimental tasks between each pair of 638 brain 
 regions. This continuous co-activation matrix was used to build a weighted
  graph to characterize network topology. We found that the co-activation n
 etwork was modular\, with occipital\, central and default mode modules pre
 dominantly co-activated by specific cognitive domains (perception\, action
  and emotion\, respectively). It also included a rich-club of hub nodes\, 
 located in parietal and prefrontal cortex and often connected over long di
 stances\, which were co-activated by a diverse range of experimental tasks
 . Investigating the topological role of edges between a deactivated and an
  activated node\, we found that such competitive interactions were most fr
 equent between nodes in different modules or between an activated rich clu
 b node and a deactivated peripheral node. Many aspects of the co-activatio
 n network were convergent with a connectivity network derived from resting
  state fMRI data (N=27\, healthy volunteers)\; although the connectivity n
 etwork was more parsimoniously and less centrally connected. We conclude t
 hat the community structure of human brain networks was related to cogniti
 ve function. Deactivations may play a role in flexible reconfiguration of 
 the network according to cognitive demand\, varying the integration betwee
 n modules\, and between the periphery and a central rich club.\n
LOCATION:BCNI seminar room\, Sir William Hardy Building\, Downing Site
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