To determine whether stimulation of dPAG neurons that elicit flight was aversive, mice carrying the Vglut2::Cre transgene were infected bilaterally with ChR2 or YFP control expressing viruses and surgically implanted with optic fibers above the infection site as above and allowed to habituate to a dual chamber real-time place preference (RTPP) apparatus. The gene discussed is SLC17A6; the disease is infection.