A limbic-system region {amygdala-hippocampal complex} measures smell associations and emotions.
Olfactory nerves, mitral cells, and tufted cells converge on olfactory-bulb spheres {glomerulus, smell} {glomeruli, smell}. Olfactory receptors send to one lateral glomerulus and one medial glomerulus. Glomeruli receive from one or more olfactory receptors and detect one odor or odor combination.
At nose tips, mammals have a ganglion {Grueneberg ganglion} that detects alarm pheromones (Hans Grueneberg) [1973].
Mammal nasal-cavity bases have smell neurons {vomeronasal system} {Jacobson's organ} {Jacobson organ} for sex-signal and other pheromones. Axons go to accessory olfactory bulb and then to amygdala [Holy et al., 2000] [Johnston, 1998] [Keverne, 1999] [Stowers et al., 2002] [Watson, 2001].
Odor receptors send output directly, left to left and right to right, to 2-mm-diameter brain region {olfactory bulb}| above and behind nose. Olfactory receptors send axons to mitral cells. Mitral-cell axons go to anterior-olfactory-nucleus and prepyriform-cortex superficial and deep pyramidal neurons. Pyramidal neurons send recurrent collateral axons to superficial pyramidal neurons and stellate cells. Pyramidal neurons have post-synaptic apical dendrites that receive from other pyramidal neurons. Tufted cells are local. Olfactory nerves, mitral cells, and tufted cells meet in olfactory-bulb glomeruli. Olfactory bulb preserves odor-receptor spatial relations. Olfactory bulb has fewer neurons than number of odor receptors.
Olfactory-bulb signals go to pyriform cortex, amygdala-hippocampal complex, and entorhinal complex {olfactory cortex}.
1-Consciousness-Sense-Smell-Anatomy
Outline of Knowledge Database Home Page
Description of Outline of Knowledge Database
Date Modified: 2022.0225