KCNQ4 and depressive disorder: The aim of this study was 3-fold: (i) to determine the projection-specific expression pattern of Kv7.4 in VTA DA neurons; (ii) to identify Kv7.4 as a target of D2 receptor-mediated auto-inhibition of VTA DA neurons; and (iii) to probe the involvement of D2-Kv7.4 pathway mechanism in a social defeat mouse model of depression.