ECoG observations of power-law scaling in the human cortex
نویسندگان
چکیده
We report the results of our search for power-law electrical signals in the human brain, using subdural electrocorticographic recordings from the surface of the cortex. The power spectral density (PSD) of these signals has the power-law form P (f) ∼ f from 80 to 500 Hz. This scaling index χ = 4.0 ± 0.1 is universal, across subjects, area in the cortex, and local neural activity levels. The shape of the PSD does not change with local cortex activity, only its amplitude increases. We observe a knee in the spectra at f0 ≃ 70 Hz, implying the existence of a characteristic time scale τ = (2πf0) −1 ≃ 2− 4 msec. For f < f0 we find evidence for a power-law with χL ≃ 2.0± 0.4.
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