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Chemesthesis, Thermogenesis, and Nutrition
Published in Alan R. Hirsch, Nutrition and Sensation, 2023
Hilton M. Hudson, Mary Beth Gallant-Shean, Alan R. Hirsch
A shared trait of traditional thermogenic foods is their ability to stimulate the common chemical sense in the mouth and throat—they taste hot (Alimohammadi and Silver 2002). Such sensation occurs as a result of small unmyelinated 1C nerve fibers firing through the trigeminal, or irritant nerve, producing the sensation of heat, burning, and in the extreme, pain (Szolcsanyi 1990). Activation of such pathways may interact with olfaction and enhance sensory-specific satiety and fullness, followed by a reduction in appetite and consumption, culminating in weight loss (Sochtig, Sochtig, and Muller 2014). Such a functional effect can be underrated given that both the primary olfactory cortex, the piriform cortex is also the site of projections from non-odorous trigeminal stimuli (Lundstrom and Albrecht 2010). This may be even more relevant given the evidence that fat perception may be mediated not through the gustatory or olfactory systems, but rather through trigeminal stimulation (Engelhardt, Hummel, Schobel, Hatt, and Landis 2010).
The Limbic System
Published in Jay A. Goldstein, Chronic Fatigue Syndromes, 2020
Piriform cortex. The functions of the piriform cortex are incompletely understood. The olfactory lobe provides chemical input to the brain via smell and is the only sensory modality that does not have thalamic relays. It has a high density of IL-1 receptors. Whales and dolphins, however, have a piriform cortex and are reported to have no sense of smell. An animal model of depression has been produced by olfactory bulbectomy.11 The piriform cortex connects directly to other limbic zone structures as well as to the hypothalamus and to the paralimbic regions.
Neuronal Networks in Convulsant Drug-Induced Seizures
Published in Carl L. Faingold, Gerhard H. Fromm, Drugs for Control of Epilepsy:, 2019
Many clinical epileptologists consider neocortical structures to be the first and foremost element involved in generalized-onset seizures,100 because certain cortical sites can act as a focus for generalized seizures. However, extensive experimental support has not been presented. In animal models a dorsal cortical area, the deep prepiriform cortex has recently received major interest as an important component of epileptogenic neuronal networks. The anterior portion of the piriform lobe is commonly known as piriform cortex, primary olfactory cortex, or prepiriform cortex. The term prepiriform cortex is generally used for primary olfactory cortex, which is bounded rostrally by the anterior olfactory nucleus, medially by the olfactory tubercle and amygdaloid body, and caudally by the entorhinal area. It receives the majority of the olfactory bulb fibers and serves as a major olfactory region in the brain.101 A highly localized site within the deep prepiriform cortex has been named the “area tempestas”, and this area has been implicated as being a very important forebrain nucleus in seizure networks.
Investigational drugs for the treatment of olfactory dysfunction
Published in Expert Opinion on Investigational Drugs, 2022
Arianna Di Stadio, Cinzia Severini, Andrea Colizza, Marco De Vincentiis, Ignazio La Mantia
The neuroepithelium is connected through the axons of the ORN to the olfactory bulb, which contains glomerulus, mitral cells and tufted relay neurons. The axons converge in the glomerulus to form the first cranial nerve (olfactory nerve). The glomerulus is connected by synapses to the mitral cells; the latter together with the tufted relay neurons forms the olfactory tract. This structure bifurcates in the medial and lateral olfactory stria (y inverted-shaped). The olfactory stimulus is conducted through these structures up to the piriform cortex, the periamygdaloid cortex, the olfactory tuberculosis and the anterior olfactory nucleus. The primary olfactory cortex is formed by the medial and lateral olfactory stria and the anterior perforated substance. The lateral olfactory stria is extended posteriorly giving origin to the entorhinal area which, together with the uncus, forms the secondary olfactory cortex, also known as the orbitofrontal cortex (Figure 2). This area is straightly related to memory. The primary cortex is responsible for the active perception of the sense of smell, while the secondary one is the portion where the smell perception is integrated with emotions and memory.
SARS-CoV-2 invasion of the central nervous: a brief review
Published in Hospital Practice, 2021
Ruqaiyyah Siddiqui, Mohammad Ridwane Mungroo, Naveed Ahmed Khan
It has been reported that in specific areas of the human brain, including substantia nigra and brain ventricles, as well as both excitatory and inhibitory neurons in the middle temporal gyrus and posterior cingulate cortex, the expression of ACE2 is high [48]. ACE2 is high in brain nuclei of various important cells, such as neural cell bodies of different neuromodulators, including dopaminergic nuclei, serotoninergic nuclei, histaminergic nuclei, and norepinephrinergic nuclei [48]. The posterior hypothalamic area (responsible for cardiovascular regulation, expression of defensive behavior and sleep-wake cycle), paraventricular nuclei of thalamus (responsible for feeding, wakefulness, appetitive motivation, regulation of stress, negative emotional behavior, and control of drug addiction), lateral hypothalamic area (responsible for control of thirst, hunger, and autonomic nervous system), and the paraventricular nuclei of hypothalamus have also been shown to highly express ACE2 [23,48,67–69]. Piriform cortex (associated with the sense of smell), amygdalo-hippocampal transition area (linked to fear manifestation), fastigial nucleus (associated with eye and body movements), and hippocampal CA2 field (linked to memory and learning) are other locations in the brain that highly express ACE2 [48,70–73]. ACE2 was also detected in excitatory neurons (linked to emotion and memory) in the parahippocampal cortex and hippocampal formation and inhibitory neurons (vital for normal brain function) [48,74,75].
Evaluating the effect of transplanting umbilical cord matrix stem cells on ischemic tolerance in an animal model of stroke
Published in Neurological Research, 2021
Mahmoud Ramdan, Mohammad Reza Bigdeli, Sepideh Khaksar, Abbas Aliaghaei
Measuring the dry and wet weights of the brain samples is one of the common ways to assess the amount of brain edema. After killing the animal and removing its brain, the olfactory bulb, cerebellum, and medulla oblongata were separated from the brain. Then, the right and left hemispheres were separated. In the same way, the brain areas including the cortex, piriform cortex-amygdala, striatum, and hippocampus were separated in both the right and left hemispheres. Afterward, they were weighed on a digital scale. The weight of the wetbrain (WW) was calculated for each of them. Then, the tissues were placed inside an incubator with a temperature of 120 °C for 24 h. The brain areas were weighed again after 24 h. The dry weight (DW) was calculated. Finally, the content of brain water was calculated using the following formula: ([WW-DW)/WW] ×100) [28].