Figure 1.

Schematic representation of the social fear conditioning (SFC) paradigm. On day 1, during SFC, the mice were placed in the conditioning chamber and, after a 30 s habituation period, an empty wire mesh cage was placed as a non-social stimulus near one of the short walls. After 3 min, the non-social stimulus was replaced by an identical cage containing an unfamiliar mouse, i.e., social stimulus. Mice were given a mild electric foot shock each time they investigated the social stimulus. On day 2, during social fear extinction, the mice were exposed in their home cages to three non-social stimuli, followed by exposure to six unfamiliar social stimuli. Twenty min before social fear extinction, the mice received the first infusion (vehicle, BIBO3304 trifluoroacetate or BIIE0246). Ten min later, the mice were infused again with either vehicle or NPY.