The striatum is a brain region that receives a neurochemical called dopamine from other brain regions to control behavior. Using mice with loss of Foxp1 specifically in the striatum, the authors found that Foxp1 regulates the structure of the striatum by altering the types of dopamine-receiving cells that develop and disrupting the connections these cells make with other parts of the brain. Interestingly, these changes only occur when Foxp1 is deleted from one subset of striatal cells. In addition, different motor and social behavioral deficits occur in these mice when Foxp1 is removed from specific cell types. Taken together, this study highlights that Foxp1 has distinct functions in the brain depending on which cells express it.