What happens during theta?

What precisely occurs during theta? Could you elaborate on the physiological processes that take place during this particular brainwave state? I'm particularly interested in understanding the neural mechanisms that underlie theta activity and how it might affect consciousness, cognition, or even emotions. Additionally, I'm curious to know if there are any specific external stimuli or conditions that typically trigger theta waves in the brain. Could you also discuss any potential benefits or applications of understanding theta in the fields of cryptocurrency and finance?