This is a great page summarizing the latest research on how meditation affects the brain.

Meditation & the Brain

by Eric Thompson

Welcome to this lens dedicated to sharing the latest scientific research on how meditation can change the brain through the training of attention. You’ll find information, videos, slides and links on how science describes the influence of meditation on the brain, as well as resources for making positive changes that will profoundly influence your brain, mind and spiritual wellbeing.

Exciting Implications from the Neuroscience of Meditation

~ Your mind can change your brain!
~ Attentional training (e.g., meditation) can significantly shift your emotional set-point (i.e., your personality)
~ Attention acts like a gate, allowing more neural information to enter specific areas of your brain
~ Temporary states that are evoked during meditation can become enduring traits when daily meditation is practiced consistently over periods of time
~ Meditation seems to activate and develop areas of the brain involved in compassion and empathy

See more at http://www.squidoo.com/contemplative-neuroscience