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SUMMARY:Information integration\, Granger causality and measuring consciou
 s level. - Adam Barrett\, University of Sussex
DTSTART:20130625T100000Z
DTEND:20130625T110000Z
UID:TALK45622@talks.cam.ac.uk
CONTACT:Mikail Rubinov
DESCRIPTION:A key challenge in the neuroscience of consciousness is to dev
 elop theoretically grounded and practically applicable quantitative measur
 es sensitive to conscious level. Such measures should be high for vivid al
 ert conscious wakefulness\, and low for unconscious states such as dreamle
 ss sleep\, coma and general anaesthesia. I begin by motivating the hypothe
 sis that\, given the basic structure of conscious experience\, conscious l
 evel must somehow correlate with the extent to which underlying neural dyn
 amics are simultaneously generating and integrating information. I will th
 en talk about two groups of proposed measures based on this hypothesis: (i
 ) measures of integrated information\, which reflect the extent to which t
 he information generated by the whole system exceeds that generated by its
  parts\; (ii) measures of causal density\, which use Granger causality to 
 quantify the overall causal interactivity in the system. I will compare an
 d contrast the two groups of measures\, both in their\nconception and in t
 heir properties in simulation\, and discuss their merits and shortcomings\
 , in theory and in practice. I then present some preliminary empirical tes
 ts of the theory from steady-state electrophysiological data: EEG data fro
 m subjects undergoing general anaesthesia and intracranial depth electrode
  data recorded during deep sleep and wakeful resting.\n
LOCATION:MRC CBU lecture theatre\, 15 Chaucer Road
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