The nervous system is divided into the Central and Peripheral nervous system. It helps us identify various senses in the surroundings like smell, vision, touch, taste and sound. Due to the realization of all these senses we are able to enjoy the beauty of various natural creations and enrich our lives. Different parts in the brain are divided for identifying the various senses. Although these organs or their receiving ends are placed at different places, the main place of activity and response is the brain. For example, even though we hear with our ears, the sense of sound reaches us due to special nerves placed inside the brain. The Olfactory bulb performs the important task of controlling the nerves related to odor in the brain system.
Olfactory bulb is a special organ that is located in forebrain of all vertebrates and accepts neural inputs related to odor which is identified by the nasal cavity cells. The olfactory bulb process all the odors when the olfactory receptor or smell receptor cells which are present further inside the olfactory bulb bring the information. These olfactory bulbs comprise of distinct round shaped glomeruli which are type of nerve tissues. These nerve tissues are created from the branching ends of receptor cell axons and the interneurons dendritic or outer branches. These cells are known as mitral cells in vertebrates and perform the function of transmitting the information to all other system of the brain.
Considered as the foremost site where the olfactory information is processed, olfactory bulb processes the information after its transduction into the epithelium of the nasal organs by receptor. Every single receptor cell is found to express just one form of receptor protein due to which around thousand various receptor cells are formed. Moreover, the similar receptor cell axons have been found to usually congregate on the similar glomerulus of the olfactory bulb. Here these axons at the site of distal primary dendrites belonging to mitral cells synapse. Due to this a map of olfactory space is produced on the olfactory bulb. Individual receptor cells in the bulb are known to respond each to different types of smells or odors due to which excitatory inputs of synaptic are resulted in the mitral cells which are scattered widely in the bulb. This reveals that the main function of olfactory bulb is to decode different outlines of synaptic input related to various odorants.
Olfactory bulb comprise of granule cell which are a type of interneuron. These granule cells are devoid of axons and hence can create inhibition at local level. This is accomplished by granule cells by giving out GABA from the dedicated spines of dendritic which are in contact with secondary and horizontally long dendrites related to mitral You do not have access to view this node.
Lesions surfacing on the nerve fibers, neuroepithelium as well as the olfactory bulb cause hampering effect on the mapping of odor receptor. The intensity and form of injury decides the effectiveness of restoration and regeneration of receptor connections of olfactory bulbs. Many times, the basal layers of cell is damaged or completely destroyed in neuroepithelium due to lesions which is simply not reversible. But if the basal layer is spared, then restoration of olfactory functioning is possible. In most cases, the extent of injury is the deciding factor for the recovery after olfactory nerve transaction. Axon growth is inhibited by the gliosis or scar tissue which is created if the olfactory nerves and olfactory bulb layers are extensively damaged by lesions. So as to make regeneration possible, axons have to circumvent or overcome these inhibitions and rewire the olfactory bulb again.
Lately newer methods to particularly lesion olfactory nerves have been evolved that do very little or no damage to the olfactory bulb. Even then regeneration of nerve fibers has several challenges in the form of spatial problems especially when the cribriform plate having the axon sheath alignments is broken or destroyed. Despite all the hurdles faced by the olfactory bulb during rewiring, olfactory system always has the capacity to create processes of new axon and can restart the olfactory bulb functional connections.