How do we perceive presence of our mind?

We have following normal states of being:

1) Awake
2) Drowsy
3) Sleep with NREM (Non Rapid Eye Movement)
4) Sleep with REM (Rapid Eye Movement)
5) Deep dreamless sleep

There are some abnormal states like semi-coma and deep coma.

In a wakeful state, we feel, we think, we decide, we react, we imagine, we observe, we relate and co-relate about innumerable things. We can be in in a stable-peaceful-happy state or disturbed-frustrated-unhappy-imbalanced state. We can find ourselves engrossed in work.

In dreams, we come across different world altogether. Our dreams can have known or unknown people, real or imaginary sequence of events. Events can be complete or incomplete (fragmented). Most of them we do not remember, some of them we may remember. Very few dreams we find meaningful.

We come to know about presence of dreamless sound sleep, when we get up and feel very fresh and alive and happy for no reason. Very few of us can be that fortunate.