Olfactory bulb

The olfactory bulb is a part of the central nervous system that receives olfactory information from olfactory receptive neurons and conveys information to the subcortical and cortical regions of the olfactory system.

In most vertebrates, the olfactory bulb is the most elongated (anterior) part of the brain, as seen in rats. However, in humans, the olfactory bulb is located on the lower side (lower side) of the brain. The olfactory bulb is isolated from the olfactory epithelium of the mammal and is supported and protected by the ethmoid plate which is perforated by the olfactory axons. Bulbs are divided into two different structures: the main olfactory bulb and the auxiliary olfactory bulb

The olfactory bulb is a structure found on the lower side (lower side) of the cerebral hemisphere, located near the front of the brain. Both hemispheres have olfactory bulbs. The olfactory bulb is attached to the cerebral hemisphere by a long stem (commonly referred to as olfactory stem or olfactory stem). The olfactory bulb is a structure indispensable for the olfactory system (odor-only system). An olfactory substance begins when odor molecules enter the nasal cavity by inhalation or ascending from the mouth (eg during chewing of food). These molecules interact with olfactory receptors, which are part of the G protein - coupled receptor family. Stimulation of these receptors results in the production of second messengers such as cyclic AMP (cAMP), which results in the release of ion channels and generation of action potentials in olfactory receptor cells.

The olfactory bulb provides the first stage of synaptic processing of sensory information in the olfactory pathway. The axons of olfactory neurons with the same odorant receptors converge to one or two glomeruli of the olfactory bulb. Mitral cells / cluster cells are secondary neurons that synapse to the olfactory axons and transmit this information to the center of the higher brain. In addition to the feedforward connection, there is also a lateral connection. Glomerular cells are inhibitory interneurons that form junctions between glomeruli and glomeruli. Granulosa cells are intervening neurons that synapse with mitral cells / cluster cells. Synaptic binding of different cell types in the olfactory bulb is used as an early stage of olfactory information processing (Shepherd et al., 2007) (Figure 23.13)