Evidence from model animal systems on fibroblast growth factor, cortical anatomy and functioning (top of each frame) converges with results from clinical studies, cortical anatomy and functioning (bottom of each frame) demonstrating how FGF may have a critical role in affective disorder psychopathology. FGF signaling contributes to normal cortical thickness and youth at risk for depression show early deficits in cortical thickness (A). The density of neurons in prefrontal cortex is reduced in both mice lacking FGF receptors and patients with bipolar disorder (B). A new target for antidepressant treatment is glial functioning in which FGF signaling plays a significant role (C). FGF receptor 1 plays a role in dentate gyrus adult neurogenesis in mice and, in patients with depression, antidepressant treatment has been correlated with increased dentate gyrus proliferation (D).