A great example of optogenetics in behavioral studies is the work of Dr. Kravitz and Dr. Kreitzer at the Kreitzer lab (currently, Kravitz works at the NIDDK in Bethesda). Let me tell you about it.
Brains are complicated. We all know that. Like an entangled bunch of wires. Still, over the years, neuroscientists have been able to map out several brain regions and their functions in behavior and physiology.