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Chemosensory Disorders and Nutrition
Published in Alan R. Hirsch, Nutrition and Sensation, 2023
Carl M. Wahlstrom, Alan R. Hirsch, Bradley W. Whitman
The olfactory bulb’s efferent fibers project into the olfactory tract and divide at the olfactory trigona into the medial and lateral olfactory striae. The striae project to the anterior olfactory nucleus, the olfactory tubercle, the amygdaloid nucleus (which in turn projects to the ventral medial nucleus of the hypothalamus, a feeding center), the cortex of the piriform lobe, the septal nuclei, and the hypothalamus, especially the anterolateral regions of the hypothalamus, which are involved in reproduction, partially explains the significance of olfactory stimuli in the reproduction process (Hirsch 1998).
Extended Anterior Skull Base Approaches
Published in R James A England, Eamon Shamil, Rajeev Mathew, Manohar Bance, Pavol Surda, Jemy Jose, Omar Hilmi, Adam J Donne, Scott-Brown's Essential Otorhinolaryngology, 2022
Carl H. Snyderman, Paul A. Gardner, Juan C. Fernandez-Miranda, Eric W. Wang
Sinonasal complications include sinusitis, epistaxis, synechiae, chronic crusting, cosmetic deformity and loss of olfaction. Delayed epistaxis is usually due to a branch of the sphenopalatine artery. A saddle-nose deformity can result from loss of septal support. Even if the olfactory nerves are preserved, some loss of olfaction is common and may be due to altered airflow patterns, mucosal oedema and crusting, post-operative irradiation or direct damage to the olfactory epithelium or olfactory tracts. Fortunately, quality of life (QoL) studies demonstrate that overall sinonasal morbidity is low.
Choroid Plexus Tumors and Meningiomas
Published in David A. Walker, Giorgio Perilongo, Roger E. Taylor, Ian F. Pollack, Brain and Spinal Tumors of Childhood, 2020
Kenneth K. Wong, Elwira Szychot, Jennifer A. Cotter, Mark Krieger
Classically, symptoms may vary widely, depending upon the location of the mass. Lesions in the cerebellopontine angle may present with symptoms of cranial neuropathy, such as loss of hearing. Cerebral convexity meningioma may present with symptoms of headache or a seizure. Meningiomas of the sphenoid wing or optic nerve may be associated with visual loss. Visual field defects may be caused by parasellar meningiomas. Mild weakness of extraocular movements has been associated with cavernous sinus meningiomas. Compression of the olfactory tract by olfactory groove or sphenoid ridge meningiomas can cause anosmia. Mental status changes with apathy and inattention may result from large subfrontal or sphenoid ridge meningiomas. Large tumors of the posterior cranial fossa can cause obstructive hydrocephalus, and can present with papilledema and classic early-morning headache. Extremity weakness can be a presenting symptom due to meningiomas at different sites. A parasagittal meningioma growing on the falx and compressing the motor strip can lead to bilateral leg weakness in the absence of a spinal cord lesion. Meningiomas of the foramen magnum may produce a subtly progressive sequence of ipsilateral arm then leg weakness, which is followed by contralateral leg and arm weakness and may be confused with multiple sclerosis. Seizures are present in approximately 30% of patients who are diagnosed with an intracranial meningioma.113 The risk of seizure is higher in association with non-skull base location, such as convexity or falcine, and tumors associated with peritumoral edema.
Representations of the olfactory bulb and tracts in images of the medieval cell doctrine
Published in Journal of the History of the Neurosciences, 2022
In 1501, German physician, philosopher, and theologian Magnus Hundt (Parthenopolitanus; 1449–1519) published Antropologium, in which he sought to explain the body from medical, philosophical, and religious perspectives, believing that humans are created in the image of God and therefore represent a microcosm of the world as God created it. Contained in this work is a complex image summarizing the anatomy of the head and brain, which includes an unusual symbol near the bridge of the nose (Figure 1; see Hundt 1501). According to the original figure legend, the figure symbol “N” indicates Caru[n]cule [i.e., caruncle], derived from the Latin word caruncula (wart). This is a paired bulbous structure from which extend projections toward a meshwork at the base of the brain (the mythical rete mirabili). The projections from the two bulbous structures appear to connect together when they reach the rete mirabili. The entire set of olfactory structures resembles a tiny pair of eyeglasses at the bridge of the nose. These bulbous structures and their projections toward the brain are, in fact, a representation of the olfactory bulbs and the olfactory tracts. This interpretation is supported by a later figure derived from Hundt’s woodcut that has a more detailed and clearer legend (vide infra).
Olfactory bulbectomy and raphe nucleus relationship: a new vision for well-known depression model
Published in Nordic Journal of Psychiatry, 2020
Halil Ozcan, Nazan Aydın, Mehmet Dumlu Aydın, Elif Oral, Cemal Gündoğdu, Sare Şipal, Zekai Halıcı
The OBs as electrocauterized and mechanically compressed in the study groups are shown (as shown in Base/Figure 1). In microscopic examinations of the OBs, atrophy, sclerosis of glomerular and tufted cells, and olfactory tract degeneration and volume loss were detected in the study groups (as shown in left upper corner/Figure 1). Morphologically deformed and apoptotic neurons were evaluated and counted separately. Neuronal damage considered as GABAergic neuronal loss besides the serotonergic ones, particularly in the lateral wings of the DRNs in which area about 15–20% of the total neurons are GABAergic neurons were seen (as shown in Figure 2(A,B)). The specimens were stained with S-100 for determining the morphological changes (as shown in Figure 3). Morphologically deformed neuron density of DRNs detected with S-100 was nearly the same as those apoptotic neurons detected with NSE (as shown in Figure 4). TUNEL staining was performed to determine apoptosis in the DR neurons (as shown in Figure 5). Apoptotic degeneration in GABA neurons was demonstrated with immunostaining method (as shown in Figure 6).
Comparison of olfactory function between neuromyelitis optica and multiple sclerosis
Published in International Journal of Neuroscience, 2018
Li-Min Li, Hui-Yue Guo, Ning Zhao, Lin-Jie Zhang, Ningnannan Zhang, Jingchun Liu, Li Yang
The OB and olfactory tract transmit signals to the olfactory cortex, which mediates complex olfactory function and processing [25]. Therefore, the differences of the olfactory cortex in patients with NMO versus those with MS were explored in this study. GM atrophy was found to be prominent in the right OFC in patients with NMO, while in patients with MS, GM atrophy was observed in the right PC and right PCG. The mechanisms of olfactory deficit in NMO and MS might be different. In keeping with this hypothesis, Liu et al. showed that early PCG atrophy might be a key feature distinguishing MS from NMO [26]. Atrophy of the PCG was demonstrated to be correlated with olfactory recognition function in patients with MS [20]. Meanwhile, both the PCG and right PC were suggested to be engaged in judging odor familiarity [27,28]. Thus, it is possible that olfactory recognition function in patients with MS relies more heavily on familiarity when multiple olfactory choices are present. Thus, the decrease in performance on tests of odor familiarity in patients with MS might be related to impaired olfactory function in the PCG.