EEG COORDINATION DYNAMICS: self-organization in the brain

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The Human Brain and Behavior Laboratory. EEG COORDINATION DYNAMICS: self-organization in the brain. http://www.ccs.fau.edu/hbbl.html. Emmanuelle Tognoli 12/17/2007 Merck – West-Point. The Human Brain and Behavior Laboratory. - PowerPoint PPT Presentation

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  • EEG COORDINATION DYNAMICS: self-organization in the brainThe Human Brain and Behavior LaboratoryEmmanuelle Tognoli 12/17/2007Merck West-Pointhttp://www.ccs.fau.edu/hbbl.html

  • IntroductionThe paradigm of EEG in cognitive neuroscienceThe Human Brain and Behavior Laboratoryhttp://www.ccs.fau.edu/hbbl.html

  • local areasinter-areal connectivity,circuits

  • Neuromarkers of social behaviorA dual EEG studyThe Human Brain and Behavior Laboratoryhttp://www.ccs.fau.edu/hbbl.html

  • SUBJECTS: Sixteen subjects (10 males, 6 females, aged between 22 and 41 years, (mean 29 years). Constituted 8 pairs: 4 gender-mixed; 3 male-male; 1 female-female. All right-handed on the basis of self-report. Had normal or corrected-to-normal vision and reported no history of neurological disease. t=20-40st=40-60st=0-20sTRIALS: 36 trials lasting 1 minute.

    Vision of the other controlled through fast-switching (1.2ms) LCD screen, turning transparent at t=20s and back to opaque at t=40s DUAL-EEG RECORDING: Dual-EEG recorded using two 60-channel EEG caps with Ag-AgCl electrodes (Falk Minow Services, Germany) arranged according to the 10 percent system (midline and rows 1 to 8), with 2 distinct referential montages.

    Signals directed to a single amplifier (Synamp2, Neuroscan, Texas) analog filtered (Butterworth, bandpass from 0.05 Hz ( -12 dB/octave) to 200 Hz (-24 dB/octave), amplified (gain= 2010) and digitized at 1000 Hz with a 24 bits ADC in the range 950 microV (vertical resolution of 0.11nV).

    Recording performed with the respective grounds located at FPz sites and the references at the corresponding linked mastoids. Impedances maintained below 10 kOhms. TASK: perform regular continuous finger movements at a comfortable pace during one minute trials. Subjects are instructed to adopt the most comfortable pace, at any time during the trial

  • Spatio-spectral patterns16.384 secFs: 1000 HzSamples: 16384Spectral Resolution: 0.06HzSpace (scalp surface): 2D Frequency: 1DAmplitude: 1D

  • +=f ERSa ERDm ERDtrouble

  • Assessment:

    method is sensitive (small change -obscured by other processes- can be detected)

    cracks-down sources of inter-individual variability

    has a good construct validity (the measure of mu is a measure of mu, not a measure of mixed processes)

    differentiates difficultly distinguishable neural activities

    essentially yields information about local areas (see after)

    The Human Brain and Behavior Laboratoryhttp://www.ccs.fau.edu/hbbl.html

  • Assessment:

    method is sensitive (small change -obscured by other processes- can be detected)

    cracks-down sources of inter-individual variability

    has a good construct validity (the measure of mu is a measure of mu, not a measure of mixed processes)

    differentiates difficultly distinguishable neural activities

    essentially yields information about local areas (see after)

    The Human Brain and Behavior Laboratoryhttp://www.ccs.fau.edu/hbbl.html

  • f1, f2a variantmx

  • Assessment:

    method is sensitive (small change -obscured by other processes- can be detected)

    cracks-down sources of inter-individual variability

    has a good construct validity (the measure of mu is a measure of mu, not a measure of mixed processes)

    differentiates difficultly distinguishable neural activities

    essentially yields information about local areas (see after)

    The Human Brain and Behavior Laboratoryhttp://www.ccs.fau.edu/hbbl.html

  • Theory of Coordination Dynamics:Self-organization of oscillatory ensemblesThe Human Brain and Behavior Laboratoryhttp://www.ccs.fau.edu/hbbl.html

  • 4p/350 msec67 msecABC0 msec

  • f = dw - a sinf - 2b sin (2f) + Qxt

  • my evidence in the past 18 years for sustained synchrony (never antiphasic), for spatial phase gradients in intracranial EEGs from high-density arrays, and for phase cones with phase velocities corresponding to intracortical axonal propagation velocities as evidence for state transitions.

    Walter Freeman

  • A0 msecElectrical:Spatial summationChemical:LTP/LTDZero-Lag Synchronization

  • Transiently Synchronized Neural Cell Assemblies:Phase Locking in the brain?

    The Human Brain and Behavior Laboratoryhttp://www.ccs.fau.edu/hbbl.html

  • Inphase in scalp EEG?

  • *Antiphase in scalp EEG?Indeed by the plenty (too many):

  • Rodriguez et al., 1999 Nature

  • broken symmetry2p

    p

    0BriefRareSmaller amplitude

  • Forward modelsWhere is the true antiphase?The same volume conduction effect that emphasizes spurious antiphase synchrony also attenuates real antiphase synchrony.

  • Forward models of source pairs:states and transitionsThe Human Brain and Behavior Laboratoryhttp://www.ccs.fau.edu/hbbl.html

  • E1: AE1: amplitude at location 1fE1:frequency at location 1fE1: phase at location 1E2: AE2: amplitude at location 1fE2: frequency at location 1fE2: phase at location 1S1: AS1: amplitude at location 1fS1:frequency at location 1fS1: phase at location 1S2: AS2: amplitude at location 1fS2: frequency at location 1fS2: phase at location 1E1=0.95*S1+p*S2E2=0.95*S2+p*S1

  • Transitions, intermittency, uncoupled areas

  • AMPLITUDE MODULATION

  • Assessment:

    While the average picture (part I):-discarded critical information (inter-areal coupling)-created intra- and inter-individual variability -occasionally created fictive properties-prevented introduction many variables/steps in protocols (parameter spaces)

    The continuous method:-yields first deterministic findings of inter-areal synchronization-has temporal resolution at the limit of recording instruments (pharmaco-dynamics)-has maximal consistency-and above all

  • Epistemological viewpoint

  • Epistemological viewpointInterest in real time behavior, especially transients: how to deal with them?

    If the temporal definition of their onset is insufficient or if their recurrence is too low (remember: average hundreds), we cannot analyze them.

    Even if we can analyze evoked activity, we may not want to seed the pseudo-real time EEG in the real-real time behavior:

    Models of EEG

  • In general, EEG amplitude IS NOT speaking about cortical source strength

  • CP4

  • Mu: wicket-shaped (en arceau)Topology: lateral parietalTopology: central/rolandiqueTopology: posterior/occipitalPhi: triangularAlpha: sinusoidal

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