The role of vasopressin in olfactory processing

The olfactory bulb is the part of the vertebrate forebrain that is involved in olfaction, the perception of odours. In this large and complex structure, olfactory signals from the nose are processed, and the results of this information processing are conveyed via the olfactory tract to brain areas involved with behavior and memory. That is why when we smell something, it often brings back memories associated with the object. Our work is focused on newly discovered nerve cells within the olfactory bulb that release the neuropeptide vasopressin. It is important to understand the role of vasopressin, because vasopressin acts in the brain to affect social behaviours, including social recognition, pair bonding, sexual behaviour and aggression. The aim of this proposal is to understand how vasopressin affects behaviour and memory within the olfactory bulb at the level of odour perception. Other nerve cells release peptides and they have effects on other emotions and behaviours and this has attracted wide attention because peptide mimetics may be valuable therapeutically for particular behavioural disorders.

Pheromones, initially delivered to the olfactory systems, can act as social signals. These signals are modulated in higher brain regions by the neuropeptides oxytocin and vasopressin to generate social recognition and behaviour. We recently discovered a population of vasopressin expressing cells in the periglumerular layer of the main and accessory olfactory bulb which appear to be a subpopulation of external tufted cells. We hypothesise that vasopressin is acting directly within the olfactory bulb and this proposal is aimed at understanding the role of vasopressin in mediating social behaviours at the first synapses after odour perception. Olfactory signalling is a topic of fundamental importance in neuroscience, and understanding peptide-dependant behaviours is of key importance for translating basic understanding into therapeutic goals. The project addresses contemporary questions in neuroscience using whole animal approaches including quantitative behavioural analysis and in vivo electrophysiology, in addition to electron microscopy, in situ hybridisation and immunocytochemistry.