SV2A and major depressive disorder: Ketamine (0.5 mg/kg) administered to monkeys and humans with major depression/post-traumatic stress disorder (PTSD) did not change SV2A binding 24 h later in the dorsolateral prefrontal cortex (dlPFC), ACC, or hippocampus, as measured with 11C-UCB-J positron emission tomography (PET) imaging (78).