LINGUIST 2PS3 Lecture Notes - Olfactory Receptor, Cerebral Cortex, Thalamus
Document Summary
Olfactory receptor neurons send axons into the two olfactory bulbs (see fig. The input layer of each bulb contains about 2000 spherical structures called glomeruli. Each glomerulus is the site of about 25 000 primary olfactory axon endings converging and terminating on dendrites of about 100 second-order olfactory neurons. The mapping of receptor cells onto glomeruli is precise. Each glomerulus receives receptor axons from a large region of the olfactory epithelium. This mapping is also consistent across the two olfactory bulbs each bulb has only two p2 (receptor gene)-targeted glomeruli, in symmetrical positions (see fig. It seems that each glomerulus receives input from only receptor cells of one particular type. This means that the array of glomeruli within a bulb is a very orderly map of the receptor genes expressed in the olfactory epithelium (see fig. Among the most important targets are the primitive region of cerebral cortex called the olfactory cortex.