Thank you so much, Martin, for your detailed response! You have made me feel much better and less anxious now when trying to sleep. Your response #5 was my thought as well. If we have a good night’s sleep the next night after one night of no sleep, why wouldn’t our brains clean out the tau as it normally does. Your #6 makes sense as well. If tau is only found in the blood, our brains are possibly just in the process of removing it from our bodies.
Thanks delv-x and jazzcat22 for your quick responses also.