The study, outlined in Brain Connectivity, measured brain activity in 19 students over the course of 17 days. 9 of those days involved actively reading parts of Pompeii by Robert Harris.
On the mornings following the reading, researchers observed higher levels of brain activity. Reading novels may also have residual effects, as increases in activity continued days after the reading was completed.
Read more about these interesting findings in the School Library Journal, or read the entire study here.
Berns, Gregory S., Blaine, Kristina, Prietula, Michael J., and Pye, Brandon E. "Short- and Long-Term Effects of a Novel on Connectivity in the Brain." Brain Connectivity 3, no. 6 (2013): 590-600. doi:10.1089/brain.2013.0166.