Olfactory Bulb
The olfactory bulb is the site of the first synaptic processing of the olfactory input from the nose. It is present in all vertebrates (except cetaceans) and a the analogous antennal lobe in most invertebrates. With its sharply demarcated cell types and histological layers, and some well-studied synaptic interactions, it is one of the first and clearest examples of the microcircuit concept in the central nervous system. The olfactory bulb microcircuit receives the information in the sensory domain and transforms it into information in the neural domain. Traditionally, it has been considered analogous to the retina in processing its sensory input, but that has been replaced by the view that it is more similar to the thalamus or primary visual cortex in processing its multidimensional input. This chapter describes the main synaptic connections and functional operations and how they provide the output to the olfactory cortex