Gamma (30-80 Hz)
Gamma Rule
We inhibit frontal Gamma from going down to ensure that the Theta in the mix is concentration Theta and not sleepy Theta. Sleepy Theta arises during drowsiness and so interferes with the ability to maintain a tight focus. Gamma is an activating frequency, so it is not likely to occur when one is sleepy. We reward increases in Gamma because high amounts of frontal Gamma arise during strong periods of concentration (Kakumanu et al. 2018).
Gamma Weights
We multiply decreases in Gamma by a rule weight of 2 for Levels 1 and 2 to make sure that the depth score goes down a lot when Gamma goes down. This ensures that one is putting out focus Theta, not sleepy Theta. Levels 3 and 4 get a rule weight of +1 for increases in Gamma to support strong concentration.