Humanized FOXP2 mice display altered cortico-basal ganglia circuits. The human allele of the FOXP2 gene was transferred into the mouse embryos through homologous recombination to create humanized FOXP2 mice. The human variant of FOXP2 also had an effect on the exploratory behavior of the mice. In comparison to knockout mice with one non-functional copy of "FOXP2", the humanized mouse model showed opposite effects when testing its effect on the levels of dopamine, plasticity of synapses, patterns of expression in the striatum and behavior that was exploratory in nature.