In contrast to GABA, acetyl choline is a slow acting neuromodulator [59], which could explain why the increase in ChAT levels seen in the mutant mice and mimicked by treating WT mice with the acetyl cholinesterase inhibitor donepezil, plays a more pronounced role during the fear extinction learning in the SPS model of PTSD-like paradigm. The gene discussed is ACHE; the disease is post-traumatic stress disorder.