I see from some other posts that relevant studies have been published recently. All of the news confirms benefits of fast paced cycling, but I don't see studies that last for a long time. Four turns on the cycle doesn't seem to me to have a high chance of changing brain function. However, as I'm an anthropologist, not a neuroscientist, I defer to those in the field.

Two years ago I was unable to ski. I had to work my way to the download station at Whistler and give up on the idea of skiing again. My shoulder was frozen and my arm very painful. I'm at Whistler again and have just finished two days of skiing at nearly the same level I had enjoyed for years. In the interim I have continued to ride my bike almost daily at the high 80-90 rpm. A few weeks ago I visited my MDS and he told me that I am still at Level 1, eight years after diagnosis and ten years after experiencing symptoms. I hear almost daily from people who are making the difficult commitment to fast pace cycling who are experiencing benefits similar to mine. It's not all perfect. I have off times nearly every day, but I find that if I keep active during the off times, I don't notice them as much. Staying away from protein during the day seems to make a big difference as well. If I eat protein at breakfast or lunch, I often have a stomachache that might last for hours. Hopefully, these observations will help.