EEG and Brain Connectivity: A Tutorial - Bio-Medical Instruments, Inc.

More documents

Recommendations

Info

This is an instantaneous cosine and sine representation of a time series from which the time series of the “cospectrum” and “quadspectrum” are computed from the cross-spectrum (see Appendix B for the mathematical details of complex demodulation). As described in section 9 the results of the CDF is the creation of a new real valued time series. The CDF real valued time series is then used as the input to spectral analyses for the computation of bi-coherence and bi-phase. 25- What is the physiological meaning of EEG Auto-Frequency Coherence (AFC) and Auto-Frequency Phase (AFP)? Cross-channel Auto-Frequency Coherence and Auto-frequency phase measure the spatial and temporal relations between EEG “spindles” or “burst activity” and “rhythmic episodes” as well as the frequency structure of EEG bursts between two channels but at the same frequency (i.e., autofrequency). Complex demodulation of a EEG time series at a given center frequency measures the instantaneous power (uV 2 ) of activity at each instant of time in a frequency band, similar to a filter except that the time series is represented in the complex domain. The frequency spectrum of “spindle activity” at a given frequency measures spindle duration and inter-spindle intervals or how common spindles are within a record and auto bi-coherence shows the phase synchrony of spindle activity at different frequencies within a channel. Cross bi-coherence measures the phase synchrony of spindle or burst activity at the same or different frequency in different channels. The FFT of the complex demodulation time series (x’ t ) computes the inter-burst frequency and average burst duration and burst rise times because x’ t is the envelope of the spindle structure of EEG events. For example, long duration bursts result in high power in the lower frequencies of the FFT spectrum. Short inter-burst intervals result in high power at higher frequencies of the FFT spectrum.
Fig. 24 – Top is filtered EEG at 25 – 30 Hz from F8 and reveals the burst structure of the EEG. Bottom is the complex demodulation (JTFA) time series of instantaneous power at 25 – 30 Hz (x’ t ) and represents the integral or envelope of burst activity in the hi-beta frequency band. Long duration bursts result in high spectral power in the lower frequencies and short inter-burst intervals result in high spectral power in the higher frequencies of the spectrum. Analyses were produced using the NeuroGuide Lexicor demo from the download at www.appliedneuroscience.com
Page 1 and 2:
(unpublished manuscript - Version 1
Page 3 and 4:
29- Definition of the Cross Channel
Page 5 and 6:
possible and this is why the cospec
Page 7 and 8:
is because there are relatively lon
Page 9 and 10:
Fig. 1 - Illustration of volume con
Page 11 and 12:
Fig. 3- Example of cospectrum (in-p
Page 13 and 14:
coefficient is a valid and importan
Page 15 and 16:
Eq. 1- r = ∑ N ∑ N ( X ( X −
Page 17 and 18: Fig. 5 - Comparisons between the Br
Page 19 and 20: to a Pearson product-moment correla
Page 21 and 22: constitute the basis for all spectr
Page 23 and 24: The frequency analysis of a time se
Page 25 and 26: That is, the cross-spectrum power i
Page 27 and 28: Demo). 11- Third Compute Coherence
Page 29 and 30: 100 90 80 70 60 50 40 30 20 10 0 0
Page 31 and 32: frame” of consciousness (Thatcher
Page 33 and 34: Fig. 9 - Various degrees and types
Page 35 and 36: Fig. 10 - Illustrations of phase re
Page 37 and 38: when the 1 st derivative of the pha
Page 39 and 40: Fig. 13 shows an example of two 10
Page 41 and 42: Figure 15 - The x-axis are differen
Page 43 and 44: Fig - 16. Top is coherence (y-axis)
Page 45 and 46: Coherence inflation is defined as a
Page 47 and 48: time over which the average is comp
Page 49 and 50: Nonetheless, “instantaneous” ph
Page 51 and 52: Example of conventional digital EEG
Page 53 and 54: score; 2- Simplification by providi
Page 55 and 56: the brain. The integration of QEEG
Page 57 and 58: Multiple frequencies and multiple m
Page 59 and 60: Example of one of the progress char
Page 61 and 62: advantage of imaging of non-cortica
Page 63 and 64: where n is the number of observatio
Page 65 and 66: Fig. 22 - Illustration of phase str
Page 67: measure of the area under the curve
Page 71 and 72: Fig. 26 - Top is the spontaneous EE
Page 73 and 74: 27- How to compute Auto-channel Cro
Page 75 and 76: 30- Cross-Channel Cross-Frequency C
Page 77 and 78: degrees or radians and is “normal
Page 79 and 80: exhibits statistically significant
Page 81 and 82: www.appliedneuroscience.com 37 - Co
Page 83 and 84: elationships as defined by the phas
Page 85 and 86: Fig. 33 - Example of phase differen
Page 87 and 88: Fig. 35 - Example of 4 different fr
Page 89 and 90: Fig. 37 - Example of a measure of c
Page 91 and 92: Fig. 39- Illustration of how cross-
Page 93 and 94: Fig. 41- Example of cross-frequency
Page 95 and 96: Gray, C.M., Konig, P., Engle, A.K.
Page 97 and 98: localization and functional connect
Page 99 and 100: 35 - 48, 2007. Thatcher, R.W., Bive
Page 101 and 102: Cannon, R., Lubar, J., Sokhadze, E.
Page 103 and 104: Lubar, J., Congedo, M. and Askew, J
Page 105 and 106: Yoo, S. S. et al. Increasing cortic
Page 107 and 108: F and likewise, F iω0t iϕ t [ y e
Page 109 and 110: 6- Phase Delay or phase difference
show all

EEG and Brain Connectivity: A Tutorial - Bio-Medical Instruments, Inc.

Create successful ePaper yourself

Delete template?

Save as template?