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The primary olfactory cortex is in the inferior part of the temporal lobe of the brain. [1] It involves the anterior olfactory nucleus, [2] the piriform cortex, [2] the olfactory tubercle, [2] part of the amygdala, [2] part of the entorhinal cortex, [2] [3] and the periamygdaloid cortex. [2] [4] Some sources state that it also includes the ...
Sometimes called the olfactory cortex, olfactory lobe or paleopallium, piriform cortical regions are present in the brains of amphibians, reptiles and mammals. The piriform cortex is among three areas that emerge in the telencephalon of amphibians, situated caudally to a dorsal area, which is caudal to a hippocampal area.
Humans have about 10 cm 2 (1.6 sq in) of olfactory epithelium, whereas some dogs have 170 cm 2 (26 sq in). A dog's olfactory epithelium is also considerably more densely innervated, with a hundred times more receptors per square centimeter. [48] The sensory olfactory system integrates with other senses to form the perception of flavor. [18]
It has been proposed that, in an olfactory environment typically composed of multiple odor components (e.g., odor of a dog entering a kitchen that contains a background coffee odor), feedback from the olfactory cortex to the olfactory bulb [26] suppresses the pre-existing odor background (e.g., coffee) via olfactory adaptation, [27] so that the ...
Additionally, dogs have much larger olfactory mucosa and a larger part of the brain dedicated to odors. Whereas in humans, 5% of the brain is dedicated to odors, in dogs this figure is 33%. Dogs are able to detect odors 9 orders of magnitude more faint than humans, who can detect odors up to 1 ppb .
Glomeruli are important waystations in the pathway from the nose to the olfactory cortex and have been found to be critical for odorant signal transduction. The olfactory receptor neurons (ORN), which originate in the nasal epithelium express only one type of olfactory receptor (OR). These ORNs then project their axons to the olfactory bulb.
The central mechanisms include the convergence of olfactory nerve axons into glomeruli in the olfactory bulb, where the signal is then transmitted to the anterior olfactory nucleus, the piriform cortex, the medial amygdala, and the entorhinal cortex, all of which make up the primary olfactory cortex.
Compared to humans, dogs have an inferior visual acuity, a superior sense of smell, and a relatively large olfactory cortex. They perform many roles for humans, such as hunting, herding, pulling loads, protection, companionship, therapy, aiding disabled people, and assisting police and the military.