Neuropeptides are neural signaling molecules that can modify affective states. (Rotzinger, 2010). The unidentified factor 1 (TUF1) is a novel neuropeptide (Tran, 2010) with high concentration in the amygdala, hippocampus, hypothalamus, and the endocrine tissue. Evidence suggests that it is secreted, and binds with low affinity to the p75 receptor. TUF1 is believed to be involved in stress regulation and may have a neuroprotective function. Contextual conditioning is a good model for anxiety disorders. Patients with PTSD exhibit abnormalities to contextual cue conditioning, but not explicit conditioning (Grillion, 1999). Using TUF1 KO mice, I studied behavioral changes in contextual conditioning compared wild type mice.