OR! ... A human is comprised of three parts, a body, a mind, and a spirit. All three manifest in the physical realm.
What's to say that the three parts of a human aren't ALWAYS existing in the three separate realms? Wouldn't that make sense considering what the three realms are? Merely transference from one to another could be anyhing. THOUGHT could be described as a stream of information from the cognitive realm as needed.
What if that gate we think needs to be held OPEN (nightblood theory) is already always open. Merely being closed by the sheath. My backup to that would be the squirrel that Lightsong awakens.. that creature has some semblance of personality and brain power, hence why you can give it a more complex command then say a bunch of sticks. But where is that brain power coming from if not from the cognitive realm? Sure as heck ain't the thing's dead brain doing it.
My brain feels good. It's active today.