|MadSci Network: Neuroscience|
You are right that a brain scan of a person's brain while reading would be extremely active. To get a picture of the specific activity associated with reading, however, researchers have to "subtract" a picture of brain activity while the person is NOT reading since the brain is always active, regardless of the activity. The areas you mention; visual cortex, language centers, etc. should show specific activity due to reading. It is likely that you are forming new neural pathways or at least strengthening ones that already exist while reading, especially if you are reading with the intent of remembering the information you are reading. However, the brain's ability to learn is innate so reading in and of itself may not enhance the ability to learn per se but if you regularly take in information through reading, being an adept reader should help you absorb information more easily in this manner. Hope that helps! Homero L. Rey, Ph.D.
Try the links in the MadSci Library for more information on Neuroscience.