The vomeronasal system (VNS) is a chemosensory system which is present in most vertebrates and is devoted to processing cues from other organisms. One of the distinctions of this system from the main olfactory system (MOS) concerns stimulus dynamics. Unlike MOS responses which are coupled to breathing and can follow a sub-second temporal scale, responses in the VNS are dictated by a relatively sluggish uptake by the vomeronasal organ (VNO) and develop over seconds. We have recently shown that in contrast to the main olfactory bulb (MOB), output neurons of the accessory olfactory bulb (AOB), do not support decoding at fine temporal scales (Yoles-Frenkel et al. 2018). However, it was not tested whether fine temporal structure can nevertheless be read by downstream processing stages of the VNS. Here, we exploited the ability of the VNS to form stimulus response associations (Marom et al. 2019), and used optogenetic stimulation in a GO-NOGO paradigm in mice. The optogenetic approach was used as it is challenging to activate one of the two systems without activating the other with natural stimuli. Our approach allowed us to selectively activate projection neurons from either the MOB or the AOB, and compare the ability of behaving, head fixed mice to discriminate various temporal patterns. I will present our latest results regarding the comparison of the two systems’ abilities to discriminate between different stimulus durations and patterns of activation. I will also present our findings concerning the comparison of the MOS and the VNS sensitivity to timing relative to the breathing phase, where we tested the ability of mice to discriminate between stimulation patterns presented at the different phases of the ongoing breathing cycle.