Frontal midline theta rhythm and gamma activity measured by sheet-type wearable EEG device

Abstract

IntroductionThe current study measured the frontal midline theta rhythm (Fmθ), which appears in the frontal midline region during the attentional focus state, using the sheet-type wearable electroencephalograph (EEG) device HARU-1, and examined the modulation of frontal gamma band activity by cognitive tasks.MethodsWe measured the frontal EEG of 20 healthy subjects using HARU-1 for 2 min during the rest eyes-closed condition and simple mental calculation task condition, respectively. Statistical analyses were conducted using permutation testing based on t-test and cluster analysis to compare the results between the resting state and the task condition.ResultsTwelve of 20 subjects showed Fmθ during the task condition. The 12 subjects with Fmθ showed significantly higher activity of the theta and gamma bands, and significantly low activity of the alpha band during the task condition compared to the resting condition. In the eight subjects without Fmθ were significantly low activity of the alpha and beta bands and no significant activity in the theta and gamma band activity during the task condition compared to the resting condition.DiscussionThese results indicate that it is possible to measure Fmθ using HARU-1. A novel finding was the gamma band activity appearing with Fmθ in the left and right frontal forehead regions, suggesting that it reflects the function of the prefrontal cortex in working memory tasks.

Neuroimaging Approach: Effects of Hot and Cold Germinated Wheat Beverages on Electroencephalographic (EEG) Activity of the Human Brain

“…Frontal midline theta activity may be related to memory processes and negatively correlated with anxiety levels [ 35 , 36 , 37 ]. Furthermore, increased frontal-midline theta was demonstrated as a parasympathetic response during meditation [ 13 ].…”

“…During EEG recording, hot and cold beverages were alternately presented in the order of hot-cold and cold-hot to acquire more reliable and accurate data. Brain waves were determined for delta (1-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), beta (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25), high beta (25-30 Hz), gamma (30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40), and high gamma (40-50 Hz) using FFT [9].…”

“…In human brain, there are five basic categories of brain waves: delta waves observed during sleep and dreaming; theta waves associated with states of deep relaxation, meditation, daydreaming, and light sleep; alpha waves typically related to relaxed but alert states, such as meditating or resting; beta waves associated with active thinking, concentration, alertness, and problem-solving; and gamma waves associated with heightened mental activity, perception, and learning [8]. Generally, EEG spectral bands applied for the analysis of brain activity are delta (1-4 Hz), theta (4-8 Hz), alpha (8)(9)(10)(11)(12), beta (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25), high beta (25)(26)(27)(28)(29)(30), gamma (30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40), and high gamma (40-50 Hz) [9]. These waves reflect neuronal electrical activity in the brain and can be affected by sleep, brain disorders, medication, and age [7].…”

Predicting postoperative delirium after cardiovascular surgeries from preoperative portable electroencephalography oscillations

“…We analyzed 2-min-resting-eyes-closed EEG data on three channels, applied a 4–75 Hz band pass filter ( 18 ) and a 60 Hz notch filter to remove the powerline interference. The power spectrum density (PSD) ( 19 ) was calculated for each channel, and the mean PSD was calculated for each frequency band (theta 4–8 Hz, alpha 8–13 Hz, beta 13–30 Hz, gamma1 30–59 Hz, gamma2 61–75 Hz). The above 5 × 3 = 15 values and their respective ratios were used as features for machine-learning analysis.…”

Decoding Attentional Task Performance Using Electroencephalogram Signals

“…Therefore, the peak frequency in the gamma range has received considerable attention [28]. Gamma band activity, combined with frontal midline theta rhythm in the left and right frontal forehead regions, appears to reflect prefrontal function in working memory tasks [29]. Furthermore, lateralized patterns of band phase coupling between the frontal and parietaloccipital regions have been identified during covert visuospatial attention tasks in healthy young adults [30].…”