RIC8B and major depressive disorder: To further establish the functional role of ACC Tiam1 in chronic pain–induced depression/anxiety-like behaviors, we specifically deleted Tiam1 from ACC neurons of Tiam1-floxed mice by bilateral injection of an rAAV8 vector expressing Cre recombinase and GFP driven by the human synapsin 1 promoter (rAAV8-hSyn-Cre-GFP).