Hi, I am currently comparing the coherence between highly and lowly hypnotic susceptible individuals for 4 frequency bands. I would like to know if I can directly compare the coherences or if I need to care for individual differences. If yes, which differences are these and how could I take care of them?
Any help would be greatly appreciated.
Many thanks
There appear to be large and durable discrepancies in the capacity for empathy between High and Low TRAIT hypnotizability people(Wickramasekera II & Szlyk 2003,Wickramasekera II 2015).
It appears that "surplus empathy "& hypersensitivity in interoception,or more specifically hypersensitivity in baroreceptor function can be a risk factor driving somatization(Wickramasekera 1979, 1986,1988,1993,1995,2003) and ANS dysregulation(Wickramasekera etal 1996 19998,Jorgensen & Zachariae 2002).
The Greenleaf et al 1992 data is on coronary bypass surgery patients in recovery in the ICU.Note the initial cardiovascular instability in ICU of of Highs and Low but not MODERATE (68% of people in the general population) TRAIT hypnotizability patients.Also note the DELAYED recovery of LOW TRAIT hypnotizable patients in the ICU (high financial cost).
Low TRAIT hypnotizability is functionally HIGH ALEXITHYMIA (LOW capacity for emotional empathy) and appears to require primary reinforcement for emotional reactivity or learning(Wickramasekera 1988)
Hello Andre,
Do you mean the coherence between certain EEG electrodes in specific frequency bands (e.g. alpha, 8-13 Hz and theta 4-8 Hz)? Because baseline coherence is influenced by volume condition properties of the head (Nunez, Nunez, & Srinivasan, 2016), we might expect differences in coherence across individuals solely due to differences in head shape and skull thickness across individuals.
It may be useful to get a baseline measure of coherence for each individual and then compare Signal-to-Noise (SNR) ratios of coherence across individuals. A ratio of alpha coherence over high gamma coherence would be one example. Another example would be to just compare increases or decreases in coherence due to some experimental manipulation.
There are coherence measures supposedly less susceptible to volume conduction, such as Phase Lag Index. However it it likely that they are still influence by volume conduction (e.g. see Peraza et al., 2012).
Nunez, M. D., Nunez, P. L., & Srinivasan, R. (2016). Electroencephalography (EEG): neurophysics, experimental methods, and signal processing. In Ombao, H., Linquist, M., Thompson, W. & Aston, J. (Eds.) Handbook of Neuroimaging Data Analysis (pp. 175-197), Chapman & Hall/CRC. Advance online publication. doi: 10.13140/rg.2.2.12706.63687 (attached)
Peraza, L. R., Asghar, A. U., Green, G., & Halliday, D. M. (2012). Volume conduction effects in brain network inference from electroencephalographic recordings using phase lag index. Journal of neuroscience methods, 207(2), 189-199.
I hope this is helpful!
Michael
I don't know much about Hypnotism, but your research sounds very interesting. Hypnotism has always been an unknown yet interesting mystery to me. However, please let me know more about the nature of the signal/data you are collecting, maybe then I will be able to help.
Michael D. Nunez Yes I mean the coherence between certain EEG electrodes in specific frequency bands. In my study I will use coherence and the imaginary part of the coherency. Comparing Signal-to-Noise- Ratios seems to a good advice. I will try this later. Thank you for your advice!
Niloy Sikder , under my most recent question you see the structure of my data. Thank you for your interest.
https://www.researchgate.net/post/Is_there_a_non-parametric_alternative_to_Two-Way_Repeated_Measures_Anova
- Badges
- Science topic
- Similar topics
- Biological Science
- Physiology
- Biosignals
- Biosignal Processing