The Journal of Neuroscience, May 3, 2006, ():
Synchronization between Background Activity and Visually Evoked Potential Is Not Mirrored by Focal Hyperoxygenation: Implications for the Interpretation of Vascular Brain Imaging
J. Neurosci. Koch et al.
26: 4940
Supplemental data
Files in this Data Supplement:
- supplemental material -
Spearman correlation coefficients (ρ) and p values (two-tailed) between deoxy-Hb and ssVEP respectively alpha-activity in single subjects and across averaged subjects (n = 22 data pairs for all correlations)
- supplemental material -
Supplemental material
- supplemental material
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Figure S1:
(a) α-power as a function of stimulation frequency extracted from the artificial dataset. The different lines denote the α-power variation assuming 3 different trial-to-trial variability levels in the VEP added to the same resting state EEG segment (black: ±50%; blue: ±150%; red: ±400%). Note that for each variability level the α-power shows an erroneous maximum at the stimulation frequency of 11 Hz resulting from the superimposed stimulus-locked VEP. (b) The VEP subtraction prior to α-power analysis efficiently eliminates the erroneous peak response at approximately 11 Hz for trial-to-trial variability up to ±150%, while still reducing the artefact at the excessively high variability level of ±400%.
- supplemental material
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Figure S2:
Example of normalization procedures prior to averaging. The ssVEP from two subjects show different resonance-peaks in the alpha-range (Fig. S2a). To preserve a sharpened resonance-peak after averaging, data were normalized to the integer of the averaged alpha-frequency across subjects (Fig. S2b). Finally the frequency-normalized data were amplitude-normalized by z-scoring (Fig. S2c). Note, these procedures were applied for ssVEP, alpha-activity, deoxy-Hb and oxy-Hb in all subjects prior to averaging.
