I can't speak to the brain scan rate. I would be surprised if the brain refreshes the whole image simultaneously at a regular rate, but what do I know.

But artificial lighting stobes with the power line frequency. I use this phenomenon when testing speeds of tape recording equipment. I have a spinning disc with lines on it, and they will strobe a pattern in the flourescent lighting. i am supposed to get out a neon strobe for this, but why bother... It is the exact same AC freq strobing either.

So if your spinning whatnot is indoors, chances are the lighting is strobing. Even putdoors, if there are artificial lights around, they will add their strobe effect to the otherwise steady solar lighting. Even on airport gateways there are high intensity lighting systrems running even in daylight often as not.

These effects can be seen in real life and are independent of any TV or film frame rates. Which have their own obvious effects.

Regardless of the source, the spacing of the spokes and their speed will have to interact with some form of strobe, whether it is film frames, flourescent lighting , or brain scanning. SO if you added more spokes, it would change the apparent speed of the phantom image, yes.