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When odors activate the olfactory pathways that lead to the limbic portion of the brain they trigger the release of neurotransmitters that affect the brain and mental state of the individual in a variety of ways. Stimuli transmitted to the limbic system cannot be consciously blocked, so all olfactory stimuli influence our emotions. [10]
The olfactory system, is the sensory system used for the sense of smell (olfaction). Olfaction is one of the special senses directly associated with specific organs. Most mammals and reptiles have a main olfactory system and an accessory olfactory system. The main olfactory system detects airborne substances, while the accessory system senses ...
The Lady and the Unicorn, a Flemish tapestry depicting the sense of smell, 1484–1500. Musée national du Moyen Âge, Paris.. Early scientific study of the sense of smell includes the extensive doctoral dissertation of Eleanor Gamble, published in 1898, which compared olfactory to other stimulus modalities, and implied that smell had a lower intensity discrimination.
The accessory olfactory bulb resides on the dorsal-posterior region of the main olfactory bulb and forms a parallel pathway. Destruction of the olfactory bulb results in ipsilateral anosmia, while irritative lesions of the uncus can result in olfactory and gustatory hallucinations. Flow of olfactory information from receptors to glomeruli layer
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.
Olfactory neurons utilize a feedback system from the levels of Ca 2+ ions to activate its adaptation to prolonged smells. Due to the fact that the olfactory signal transduction uses a second messenger transduction system, the mechanism of adaptation includes several factors that mostly include CaMK or calmodulin bound to Ca 2+ ions.
Unlike the main olfactory bulb that sends neuronal signals to the olfactory cortex, the VNO sends neuronal signals to the accessory olfactory bulb and then to the amygdala, BNST, and ultimately hypothalamus. Since the hypothalamus is a major neuroendocrine center (affecting aspects of reproductive physiology and behavior as well as other ...
Neuromodulation exists in the olfactory system and is responsible for neural plasticity and behavioural change in both mammals and insects. [4] In the context of olfactory memory, neuromodulators regulate storage of information in a way that maintains the significance of the olfactory experience. [4]