Fig. 2
From: Abnormality of visual neuromagnetic activation in female migraineurs without aura between attacks
Time-frequency analysis of visual-evoked magnetic fields (VEFs): An example of the results from time-frequency analysis recorded from a migraine subject and a healthy control. Polarity spectrograms and contour maps (second and fourth) of neuromagnetic signals showed a focal activation (lighting color bar) in 5–30 Hz in the low frequency band (50-100 Hz) and 100-300 Hz in the high frequency range during a visual stimulus. There is increased spectral power in the two frequency bands of 100–300 and 500–700 Hz in the polarity spectrograms. The contour maps showed a similar activation pattern of visual evoked magnetic fields (VEF) in migraines and controls