Table 1. Number of animals studied and number of litters sampled for each experiment.

	NS group		PS group
	n	Nb of litters	n	Nb of litters
Short-term memory test	8	4	8	6
Go/No Go task	13	9	12	9
CldU-IR cell nb in OB	28	23	22	21
CldU-IR cell nb in DG	28	21	21	20
DCX-IR cell nb in DG	29	21	21	20