EEG COORDINATION DYNAMICS: EEG COORDINATION DYNAMICS: self-organization in the brainself-organization in the brain

The Human

Brain and Behavior

Laboratory

Emmanuelle Emmanuelle Tognoli Tognoli

12/17/200712/17/2007Merck – West-PointMerck – West-Point

http://www.ccs.fau.edu/hbbl.html

IntroductionIntroductionThe paradigm of EEG The paradigm of EEG

in “cognitive neuroscience”in “cognitive neuroscience”

The Human

Brain and Behavior

Laboratory

http://www.ccs.fau.edu/hbbl.html

local areas

inter-areal connectivity,

circuits

Neuromarkers of social behaviorNeuromarkers of social behaviorA dual EEG studyA dual EEG study

The Human

Brain and Behavior

Laboratory

http://www.ccs.fau.edu/hbbl.html

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

t=20-40st=20-40s t=40-60st=40-60st=0-20st=0-20s

TRIALS: TRIALS: 36 trials lasting 1 minute.36 trials lasting 1 minute.

Vision of the other controlled Vision of the other controlled through fast-switching (1.2ms) LCD through fast-switching (1.2ms) LCD screen, turning transparent at screen, turning transparent at t=20s and back to opaque at t=40s t=20s and back to opaque at t=40s

DUAL-EEG RECORDING:DUAL-EEG RECORDING: Dual-EEG recorded using two 60- Dual-EEG recorded using two 60-channel EEG caps with Ag-AgCl electrodes (Falk Minow channel EEG caps with Ag-AgCl electrodes (Falk Minow Services, Germany) arranged according to the 10 percent Services, Germany) arranged according to the 10 percent system (midline and rows 1 to 8), with 2 distinct referential system (midline and rows 1 to 8), with 2 distinct referential montages. montages.

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

Recording performed with the respective grounds located at Recording performed with the respective grounds located at FPz sites and the references at the corresponding linked FPz sites and the references at the corresponding linked mastoids. Impedances maintained below 10 kOhms. mastoids. Impedances maintained below 10 kOhms.

TASK:TASK: perform regular continuous finger perform regular continuous finger movements at a comfortable pace during movements at a comfortable pace during one minute trials. Subjects are instructed to one minute trials. Subjects are instructed to adopt the most comfortable pace, at any adopt the most comfortable pace, at any time during the trialtime during the trial

Spatio-spectral patterns

16.384 sec

Fs: 1000 Hz

Samples: 16384

Spectral Resolution: 0.06Hz

Space (scalp surface): 2D

Frequency: 1D

Amplitude: 1D

+

=

ERS

ERD

ERD

trouble

Assessment:Assessment:

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

cracks-down sources of inter-individual variabilitycracks-down sources of inter-individual variability

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

differentiates difficultly distinguishable neural differentiates difficultly distinguishable neural activitiesactivities

essentially yields information about local areas (see essentially yields information about local areas (see after)after)

The Human

Brain and Behavior

Laboratory

http://www.ccs.fau.edu/hbbl.html

Assessment:Assessment:

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

cracks-down sources of inter-individual variabilitycracks-down sources of inter-individual variability

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

differentiates difficultly distinguishable neural differentiates difficultly distinguishable neural activitiesactivities

essentially yields information about local areas (see essentially yields information about local areas (see after)after)

The Human

Brain and Behavior

Laboratory

http://www.ccs.fau.edu/hbbl.html

variant

Assessment:Assessment:

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

cracks-down sources of inter-individual variabilitycracks-down sources of inter-individual variability

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

differentiates difficultly distinguishable neural differentiates difficultly distinguishable neural activitiesactivities

essentially yields information about local areas (see essentially yields information about local areas (see after)after)

The Human

Brain and Behavior

Laboratory

http://www.ccs.fau.edu/hbbl.html

Theory of Coordination Dynamics:Theory of Coordination Dynamics:Self-organization of oscillatory Self-organization of oscillatory

ensemblesensembles

The Human

Brain and Behavior

Laboratory

http://www.ccs.fau.edu/hbbl.html

0

/2

/2

0

/2

/2

0

/2

/2/3

50 msec

67 msecA B C

0 msec

= - a sin - 2b sin (2) + Qt

“…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

0

/2

/2

A0 msec

Electrical:Spatial summation

Chemical:LTP/LTD

Zero-Lag SynchronizationZero-Lag Synchronization

Transiently Synchronized Neural Cell Transiently Synchronized Neural Cell Assemblies:Assemblies:

Phase Locking in the brain?Phase Locking in the brain?

The Human

Brain and Behavior

Laboratory

http://www.ccs.fau.edu/hbbl.html

Inphase in scalp EEG?

28

Antiphase in scalp EEG?

Indeed by the plenty (too many):

Rodriguez et al., 1999 Nature

broken symmetry

= - a sin - 2b sin (2) + Qt

BriefRare

Smaller amplitude

Forward models

Where is the true antiphase?The same volume conduction effect that

emphasizes spurious antiphase synchrony also attenuates real

antiphase synchrony.

Forward models of source pairs:Forward models of source pairs:states and transitionsstates and transitions

The Human

Brain and Behavior

Laboratory

http://www.ccs.fau.edu/hbbl.html

E1: AE1: amplitude at location 1fE1:frequency at location 1E1: phase at location 1

E2: AE2: amplitude at

location 1fE2: frequency at location

1E2: phase at location 1

S1: AS1: amplitude at location 1fS1:frequency at location 1S1: phase at location 1

S2: AS2: amplitude at

location 1fS2: frequency at location

1S2: phase at location 1

E1=0.95*S1+p*S2

E2=0.95*S2+p*S1

Transitions, intermittency, uncoupled areas

AMPLITUDE MODULATION

AssessmentAssessment::

While the While the average picture average picture (part I):(part I):-discarded critical information (inter-areal coupling)-discarded critical information (inter-areal coupling)

-created intra- and inter-individual variability -created intra- and inter-individual variability -occasionally created fictive properties-occasionally created fictive properties

-prevented introduction many variables/steps in -prevented introduction many variables/steps in protocols (parameter spaces)protocols (parameter spaces)

The The continuous methodcontinuous method::-yields first deterministic findings of inter-areal -yields first deterministic findings of inter-areal

synchronizationsynchronization-has temporal resolution at the limit of recording -has temporal resolution at the limit of recording

instruments (pharmaco-dynamics)instruments (pharmaco-dynamics)-has maximal consistency-has maximal consistency

-and above all…-and above all…

In general, EEG amplitude

IS NOT speaking about cortical source

strength