It is when the mind and ego cease to dominate our every thought and we just bask in a state of no thought without the constant running commentary of mid.
I don’t know the physiological reasons but I do know that this is the goal of meditation practice.
Thanks for the responses, but I’m looking more for a medical/biological answer. Just curious about the nature of it; evolutionary purpose, is there a clinical benefit, etc.
I doubt there is a single physical or medical answer. It depends on the underlying cause. My grandson is high functioning autistic, and he has frequent episodes. When he was younger, we would tease, saying “Earth to AL”, thinking he just wasn’t paying attention. Once he was diagnosed, we stopped.