Dynamics of high frequency brain activity

Abstract

Evidence suggests that electroencephalographic (EEG) activity extends far beyond the traditional frequency range. Much of the prior study of >120 Hz EEG is in epileptic brains. In the current work, we measured EEG activity in the range of 200 to 2000 Hz, in the brains of healthy, spontaneously behaving rats. Both arrhythmic (1/f-type) and rhythmic (band) activities were identified and their properties shown to depend on EEG-defined stage of sleep/wakefulness. The inverse power law exponent of 1/f-type noise is shown to decrease from 3.08 in REM and 2.58 in NonREM to a value of 1.99 in the Waking state. Such a trend represents a transition from long- to short-term memory processes when examined in terms of the corresponding Hurst index. In addition, treating the 1/f-type activity as baseline noise reveals the presence of two, newly identified, high frequency EEG bands. The first band (ψ) is centered between 260–280 Hz; the second, and stronger, band is a broad peak in the 400–500 Hz range (termed ω). Both of these peaks display lognormal distributions. The functional significance of these frequency bands is supported by the variation in the strength of the peaks with EEG-defined sleep/wakefulness.

Detection and estimating the blood accumulation volume of brain hemorrhage in a human anatomical skull using a RF single coil

“…Brain activity produces electrical signals (EEG). However, the frequency range of the electrical activity in the brain is much lower (1-2,000 Hz) (Moffett et al, 2017) than the operating range of the system proposed in this article (100-1,000 MHz). Therefore, the electrical signals from the brain activity do not actually affect the signal transmitted/ received from the measurement system.…”

Peer Review #1 of "Detection and estimating the blood accumulation volume of brain hemorrhage in a human anatomical skull using a RF single coil (v0.1)"

“…Brain activity produces electrical signals (EEG). However, the frequency range of the electrical activity in the brain is much lower (1-2000Hz) (Moffett et al, 2017) than the operating range of the system proposed in this paper (100-1000MHz). Therefore, the electrical signals from the brain activity do not actually affect the signal transmitted/received from the measurement system.…”

Differential Electrographic Signatures Generated by Mechanistically-Diverse Seizurogenic Compounds in the Larval Zebrafish Brain

“…Next, the mean normalised spectra for each fish were averaged within treatment groups (see Figure 6B). Finally, normalised spectra were binned into frequency bands used for studying mammalian and human EEG data (Moffett et al, 2017;Wang et al, 2020). These bands were: δ (1-4 Hz), θ (4-7 Hz), α/μ (8-13 Hz), β (beta, 15-30 Hz), γ (gamma, 30-80 Hz) and high γ (80-150 Hz) and HFO (150-500 Hz).…”