Two types of cells in the mitral cell layer process and send information. Mitral cells are large neurons with thick dendrites extending into the glomerular layer. These neurons send their axons to the higher brain. This area also contains numerous neurons called ruffed cells. This population of neurons constitutes the origin of the secondary olfactory tract, communicating to various regions in the telencephalon and diencephalon.
Granule cells reside in the central aspect of the olfactory bulb, the internal cell layer.
These cells were thought to serve exclusively as interneurons, forming dendro-dendritic synapse with mitral and ruffed neurons. Insert figure 3 here. Midsagittal view of the salmon brain. The diencephalon contains the preoptic area and hypothalamus. The olfactory projections within the telencephalon follow two distinct paths, the lateral olfactory tract and the medial olfactory tract.