Check out this paper from Germany to see what a well-studied brain looks like:
Researchers performed quantitative measurements of medical students preparing for their end of the second year exams. Serial scanning identified increases in gray matter following their training period - but a different pattern (different sites as well as different time course for increas) was seen depending on whether the students were scanned 1-2 days after the exam or 3 months later.
Parietal lobe activation probably correlated with direct sensory and representational learning (the students were studying biology, chemistry, biochemistry, anatomy, physics, anatomy, and physiology).
By the time 3 months had past, increased gray matter was still seen in the parietal lobes, but new learning effects on the brain continued - probably because of greater stabilization of the new information (spatial, semantic) in long term memory files.
Gray Matter Increases with Extensive Studying