What is theta activity?

Theta activity refers to a specific pattern of brain waves associated with the transitional state between wakefulness and sleep. This type of brain wave is dominant during certain phases like when you're falling asleep or in a deep meditative or dreamlike state. Interestingly, theta waves can be observed when the brain exhibits freer, more creative thinking, or a state of deep relaxation.

In the context of discussing the effects of the drug Ketamine, Andrew Huberman explains that the drug can abolish typical alpha patterns of brain activity, which are usually associated with a calm, alert, and relaxed state. Instead, under the influence of Ketamine, the theta pattern of brain activity emerges more dominantly. This pattern is similar to what occurs as you transition into sleep, characterized by dreamlike, vivid forms of thought 1.