Andrew Huberman· PhD
The preoptic area also can send electrical signals to the amygdala, a brain area that is often talked about in the context of fear, but is really just a brain area that can activate your sympathetic nervous system. The sympathetic nervous system is part of your autonomic nervous system and is the one associated with fight or flight, or with the stress response, or even just the excited response. The sympathetic nervous system is also what gets activated when you're really excited about something. The preoptic area has the opportunity to trigger the activation of the amygdala. Now, it doesn't do it every time, but it can. And it tends to do that when you are suddenly in an environment that feels too hot, that you feel is risky levels of hot.