brainwave entrainment and beyond: toward holistic approach
DESCRIPTION
Brainwave Entrainment and Beyond: Toward Holistic Approach. Prof. Emil Jovanov Electrical and Computer Engineering Department The University of Alabama in Huntsville Huntsville, Alabama http://www.ece.uah.edu/~jovanov [email protected]. Brainwave Entrainment. Goal? Subject in a loop - PowerPoint PPT PresentationTRANSCRIPT
Brainwave Entrainment and Beyond: Toward Holistic
Approach
Prof. Emil JovanovProf. Emil Jovanov
Electrical and Computer Engineering DepartmentElectrical and Computer Engineering DepartmentThe University of Alabama in HuntsvilleThe University of Alabama in Huntsville
Huntsville, AlabamaHuntsville, Alabama
http://www.ece.uah.edu/~jovanovhttp://www.ece.uah.edu/[email protected]@ece.uah.edu
Brainwave Entrainment Symposium, Stanford, May 2006
Brainwave Entrainment
Goal?Goal? Subject in a loopSubject in a loop
Open loop vs. Closed loop Open loop vs. Closed loop Driving vs. Biofeedback Driving vs. Biofeedback Exact frequency, current state of the userExact frequency, current state of the user
Range of EEG frequencies below audible Range of EEG frequencies below audible frequency rangefrequency range Rhythmic stimulationRhythmic stimulation Binaural beat stimulationBinaural beat stimulation
Multimodal stimulation and biofeedbackMultimodal stimulation and biofeedback AuditoryAuditory Photic drivingPhotic driving VibrationVibration
Brainwave Entrainment Symposium, Stanford, May 2006
Functional brain
EElectrical activity recording techniqueslectrical activity recording techniques EEGEEG ( (EElectrolectroEEncephaloncephaloGGraphy)raphy) ERPERP ( (EEvent vent RRelated elated PPotentials)otentials) ECoGECoG ( (EElectrolectroCCorticoorticoGGraphy)raphy) MEG MEG ((MMagnetoagnetoEEncephaloncephaloGGraphy)raphy)
fMRIfMRI ((ffunctional unctional MMagnetic agnetic RResonanceesonance PET, PET, SPECT SPECT ((PPositron or ositron or SSingle ingle PPhoton hoton
EEmission mission TTomography)omography) IIRR ImagingImaging MRIMRI Spectroscopy Spectroscopy
Brainwave Entrainment Symposium, Stanford, May 2006
Spectral analysis
absolute powerabsolute power (the amount of energy within (the amount of energy within a particular frequency band)a particular frequency band)
relative powerrelative power (proportional contribution of (proportional contribution of certain frequency band in the total power certain frequency band in the total power spectrum) spectrum)
mean/peak frequencymean/peak frequency inter/intrahemispheric differencesinter/intrahemispheric differences coherencecoherence (measure of synchronicity between (measure of synchronicity between
two electrode sites)two electrode sites)
Brainwave Entrainment Symposium, Stanford, May 2006
Brainwave Frequencies
Frequency band
Frequency Physiological role
Gamma ( ) 40-60 Hz Individual Neurons
Beta ( ) 12-30 Hz Mental Activity
Alpha ( ) 8-12 Hz Awake state
Theta ( ) 4- 8 Hz REM sleep, meditation
Delta ( ) 1-4 Hz Deep sleep
sub - Delta < 1Hz -
Hypothetical representation
Individual neurons
Specialized regions
Physical consciousness
Mental consciousness
Higher level of consciousness
Collective consciousness
EEG Correlates of Conscious States
BehavioralContinuum
EEGCharacteristics
State ofAwareness
Efficiency
Strong, exci-ted emotion;fear, rage,anxiety
Desynchronized: lowto moderateamplitude; fastmixed frequencies
Restricted awareness;divided attention;diffuse, hazy;"confusion"
Poor: lack ofcontrol, freezingup, disorganized
Alertattentiveness
Partially synchro-nized: mainly fastlow-amplitude waves
Selective attention,but may vary or shift;"concentration"anticipation; "set"
Good: efficient,selective, quickreactions; orga-nized for serialresponses
Relaxedwakefulness
Synchronized:optimal alpha rhythm
Attention wanders –not forced; favors freeassociation
Good: routinereactions andcreative thought
EEG Correlates of Conscious States (II)
BehavioralContinuum
EEGCharacteristics
State ofAwareness
Efficiency
Drowsiness Reduced alpha andoccasionallow-amplitudeslow waves
Borderline partialawareness; imageryand reverie; dreamlikestates
Poor:uncoordinated,sporadic, lackingsequential timing
Light sleep Spindle bursts andslow waves (larger);loss of alphas
Markedly reducedconsciousness (loss ofconsciousness); dreamstate
Absent
Deep sleep Large and very slowwaves (synchronybut on slow timebases); randomirregular patterns
Complete loss ofawareness (nomemory of stimulationor dreams)
Absent
Coma Isoelectric toirregular large slowwaves
Complete loss ofconsciousness; little orno response tostimulation; amnesia
Absent
Brainwave Entrainment Symposium, Stanford, May 2006
Correlates of Altered States of Consciousness
Establishing Establishing alpha activityalpha activity during epochs with during epochs with opened eyes (Hirai60)opened eyes (Hirai60)
Increased Increased amplitude of alpha activityamplitude of alpha activity (Hirai60, (Hirai60, Banquet72, Wallace72)Banquet72, Wallace72)
Slower frequencySlower frequency of alpha rhythm (Hirai60 , of alpha rhythm (Hirai60 , Banquet72, Wallace72)Banquet72, Wallace72)
Rhythmical theta wavesRhythmical theta waves (Hirai60, Banquet72, (Hirai60, Banquet72, Wallace72)Wallace72)
Increased synchronization Increased synchronization ((hypersynchronizationhypersynchronization Banquet72) Banquet72)
Dissociation of perceptionDissociation of perception from the external from the external sense organs (Hirai60, Ray88)sense organs (Hirai60, Ray88)
Brainwave Entrainment Symposium, Stanford, May 2006
Correlates of Altered States of Consciousness (II)
Occasional Occasional fast wave activityfast wave activity (Banquet73, (Banquet73, Ray88)Ray88)
Synchronous Theta BurstsSynchronous Theta Bursts (Hebert77). (Hebert77). Increased Increased intrahemispheric coherenceintrahemispheric coherence in the in the
alpha and theta frequency bands (Farrow82).alpha and theta frequency bands (Farrow82). Autonomous nervous system changesAutonomous nervous system changes Transcendent signalTranscendent signal (Ray94) (Ray94)
Brainwave Entrainment Symposium, Stanford, May 2006
Fundamental problems
Subjective time-frame (reference)Subjective time-frame (reference) Signal processing requirementsSignal processing requirements
Subjective time-frame (transcendence?)
t’ = (t)
t
t’
Mind
Measurementequipment
non linear function
Brainwave Entrainment Symposium, Stanford, May 2006
Signal Processing Requirements
Most processing algorithms require Most processing algorithms require large number of sampleslarge number of samples FFT of 1024 points @ 256 Hz FFT of 1024 points @ 256 Hz 4 seconds 4 seconds Time-frequency tradeoffTime-frequency tradeoff
Wavelet analysisWavelet analysis
Short events are lost Short events are lost
Brainwave Entrainment Symposium, Stanford, May 2006
EEG visualization methods
Brainwave Entrainment Symposium, Stanford, May 2006
Sonification - advantages
Faster processing than visual presentation
Easier to focus and localize attention in space (appropriate for sound alarms)
Good temporal resolution Additional information channel Possibility to present multiple data
streams
Brainwave Entrainment Symposium, Stanford, May 2006
Sonification - disadvantages
Difficult perception of precise quantities Difficult perception of precise quantities and absolute values. and absolute values.
Limited spatial distributionLimited spatial distribution Some sound parameters are not Some sound parameters are not
independent (pitch depends on loudness) independent (pitch depends on loudness) Interference with other sound sourcesInterference with other sound sources Absence of persistenceAbsence of persistence Dependent on individual user perceptionDependent on individual user perception
Brainwave Entrainment Symposium, Stanford, May 2006
Sonification - approaches
RhythmRhythm PitchPitch subjective perception of frequency subjective perception of frequency TimbreTimbre characteristic of instrument characteristic of instrument
generating sounds generating sounds Loudness Loudness (volume) (volume) Location Location of sound sourceof sound source
balancebalance of stereo sound of stereo sound
Brainwave Entrainment Symposium, Stanford, May 2006
Rhythm
Very powerful methodVery powerful method Natural use of very low frequenciesNatural use of very low frequencies
Delta and Theta frequenciesDelta and Theta frequencies Complex patterns is sub-Delta bandComplex patterns is sub-Delta band
Brainwave Entrainment Symposium, Stanford, May 2006
Binaural Entrainment
Excellent solution for Excellent solution for low frequencies low frequencies Brainwave frequenciesBrainwave frequencies
Superposition of two Superposition of two audio channels with audio channels with small difference in small difference in basic frequencybasic frequency L: 1000 HzL: 1000 Hz R: 1007 HzR: 1007 Hz Generated: Generated:
1007-1000=7Hz1007-1000=7Hz Fine control of the Fine control of the
entrained frequencyentrained frequency
Brainwave Entrainment Symposium, Stanford, May 2006
Holistic Approach
Mental processes Mental processes (EEG)(EEG)
BreathingBreathing Heart rateHeart rate
Cardiovascular Cardiovascular systemsystem
Glands & HormonsGlands & Hormons Body functionsBody functions
Brainwave Entrainment Symposium, Stanford, May 2006
Example #1: Yogic breathing (1 b/min)
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During
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LF/HF=146
Brainwave Entrainment Symposium, Stanford, May 2006
Example #2: Chanting
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Brainwave Entrainment Symposium, Stanford, May 2006
The Awakened Mind (C. Maxwell Cade) The importance of different frequency The importance of different frequency
bandsbands Holistic approachHolistic approach
L RL R
Frequency
Brainwave Entrainment Symposium, Stanford, May 2006
Conclusions
Subtle processes require sophisticated Subtle processes require sophisticated processing and presentationprocessing and presentation Flexible software supportFlexible software support
System customizationSystem customization Biofeedback Biofeedback
Multimodal stimulation Multimodal stimulation very effective very effective Improves immersionImproves immersion Issue: customization and maximizing Issue: customization and maximizing
perceptual distance perceptual distance Goal: becoming ONEGoal: becoming ONE