This paper deals with a new type of access to gating function in the brain, namely the comparison of the N100 auditory responses to an overt tone burst, and its inhibition when paired with a weak (i.e. auditory click but small in amplitude) prepulse. A beginning of neuropharmacological characterisation has been made in healthy subjects in order to get a hand on a potential clinical application elaborating the most advanced mechanistic basis for negative symptoms in schizophrenia.