When someone moves, time slows down for him. Let, a man standing still and another moving very very very fast, this happens for an hour (as measured by the standing man). Time has moved slower for the moving man than for the still man. The fast has got less aged than the still. I've heard that length shortens for a thing when it moves. The faster it moves, length shortens more. I'm eager to know that; when a man is moving very fast while reading a book, will he comprehend the book's items faster than when he stands still while reading this same book? (I've thought neurons get smaller and impulses travelling lesser.)
In the co-moving frame (the frame attached to him), everything is what it is, including biological laws. Moving faster won't make you smart but out-of-date.
Probably not, since the neurons are moving in the same frame of reference as the book and the reader.
However, he will have had less time to read than the person standing still, so will have learned less, etc. Think of the classic twins separated by a fast, long spaceship ride: Upon return, the young one steps out of the rocket to meet his older (wiser) twin.
Distance shortens but time interval increases, so the speed for a signal to go from one synapse to an other remains the same (as does the IQ of the spaceman).