Iota oscillations (25-35 Hz) during wake and REM sleep in children and young adults
High-frequency brain oscillations in humans are currently categorized into beta (13-30 Hz) and gamma (>30 Hz). Here, I introduce a new class of oscillations between 25 and 35 Hz, which I propose to call "iota." Iota oscillations have low amplitudes but can still be measured with surface electroencephalography (EEG). Within an individual, iota has a narrow spectral bandwidth of 2-4 Hz, thus distinguishing it from broadband beta and gamma. Iota oscillations occur as sustained bursts during both wakefulness and REM sleep but do not appear during NREM sleep. They are only found in a minority of individuals, more in children than in adults. Overall, iota oscillations are challenging to detect but could serve as a marker of both brain development and states of vigilance.