The DEn receives dense projections from neurons in several areas of the brainstem that express neuropeptide-S as a neurotransmitter (Meis et al., 2008); and parallels can be drawn between the RLN3 and neuropeptide-S systems, as excitatory, neuropeptide-S projections to the DEn have been implicated in anxiety and fear processes triggered by context, but not by a cue (Meis et al., 2008). The gene discussed is NPS; the disease is Anxiety.