To eliminate the effects of potential confounding factors of n-3 diets and to further explore the mechanism by which n-3 PUFAs modulate microglial M1 and M2 phenotypes (astrocytes producing neurotrophin and receptor functions in depression), we utilized the transgenic Fat-1 mice, which convert n-6 PUFA to n-3 PUFA in the brain [13]. Here, FAT1 is linked to major depressive disorder.