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Cranial Nerves
Cranial Nerves (1,5,7,8,9,10,11 and 12) Slides not included 9th and 10th Cranial 11th and 12th Cranial 8th Cranial Nerve 5th and 7th Cranial 1st Cranial Nerve Nerves Nerves Nerves (3,7,11,12,13,21,23,24) - (10,16) (12,23) Slides included: (14 to 17) *Slides that are not included mostly are slides of summaries or pictures. Nouf Alabdulkarim. Med 435 Olfactory Nerve [The 1st Cranial Nerve] Special Sensory Olfactory pathway 1st order neuron Receptors Axons of 1st order Neurons Olfactory receptors are specialized, ciliated nerve cells The axons of these bipolar cells 12 -20 fibers form the that lie in the olfactory epithelium. true olfactory nerve fibers. Which passes through the cribriform plate of ethmoid → They join the olfactory bulb Preliminary processing of olfactory information It is within the olfactory bulb, which contains interneurones and large Mitral cells; axons from the latter leave the bulb to form the olfactory tract. nd 2 order neuron • It is formed by the Mitral cells of olfactory bulb. • The axons of these cells form the olfactory tract. • Each tract divides into 2 roots at the anterior perforated substance: Lateral root Medial root Carries olfactory fibers to end in cortex of the Uncus & • crosses midline through anterior commissure adjacent part of Hippocampal gyrus (center of smell). and joins the uncrossed lateral root of opposite side. • It connects olfactory centers of 2 cerebral hemispheres. • So each olfactory center receives smell sensation from both halves of nasal cavity. NB. Olfactory pathway is the only sensory pathway which reaches the cerebral cortex without passing through the Thalamus . -
Early Aging Effect on the Function of the Human Central Olfactory System
Journals of Gerontology: Biological Sciences cite as: J Gerontol A Biol Sci Med Sci, 2017, Vol. 72, No. 8, 1007–1014 doi:10.1093/gerona/glw104 Advance Access publication June 11, 2016 Original Article Early Aging Effect on the Function of the Human Central Downloaded from https://academic.oup.com/biomedgerontology/article/72/8/1007/2629931 by guest on 27 September 2021 Olfactory System Choice Editor’s Jianli Wang,1 Xiaoyu Sun,1 and Qing X. Yang2 1Department of Radiology, Pennsylvania State University College of Medicine, Hershey. 2Departments of Radiology and Neurosurgery, Pennsylvania State University College of Medicine, Hershey. Address correspondence to Jianli Wang, MD, PhD, Department of Radiology, Pennsylvania State University College of Medicine, Hershey, PA 17033. E-mail: [email protected] Received November 23, 2015; Accepted April 27, 2016 Decision Editor: Rafael de Cabo, PhD Abstract During normal aging process, the smell function declines significantly, starting from the sixth decade of age. While it has been shown that activity in the central olfactory system of seniors responding to odor stimulation is significantly less than that of young people, no information of the aging effect on the functions of this system during normal adulthood and early aging has been gathered. In this study, we used functional magnetic resonance imaging to investigate the olfaction-related brain activity in the central olfactory structures of 43 healthy adult volunteers aged from 22 to 64 years. The participants’ smell identification function was negatively correlated with age (r = −.32, p = .037). Significant negative correlation was observed between age and the olfaction-related activities in the bilateral dorsolateral prefrontal cortex, left insular cortex, and left orbitofrontal cortex (p < .001, corrected with cluster size ≥28 voxels). -
Cranial Nerve Palsy
Cranial Nerve Palsy What is a cranial nerve? Cranial nerves are nerves that lead directly from the brain to parts of our head, face, and trunk. There are 12 pairs of cranial nerves and some are involved in special senses (sight, smell, hearing, taste, feeling) while others control muscles and glands. Which cranial nerves pertain to the eyes? The second cranial nerve is called the optic nerve. It sends visual information from the eye to the brain. The third cranial nerve is called the oculomotor nerve. It is involved with eye movement, eyelid movement, and the function of the pupil and lens inside the eye. The fourth cranial nerve is called the trochlear nerve and the sixth cranial nerve is called the abducens nerve. They each innervate an eye muscle involved in eye movement. The fifth cranial nerve is called the trigeminal nerve. It provides facial touch sensation (including sensation on the eye). What is a cranial nerve palsy? A palsy is a lack of function of a nerve. A cranial nerve palsy may cause a complete or partial weakness or paralysis of the areas served by the affected nerve. In the case of a cranial nerve that has multiple functions (such as the oculomotor nerve), it is possible for a palsy to affect all of the various functions or only some of the functions of that nerve. What are some causes of a cranial nerve palsy? A cranial nerve palsy can occur due to a variety of causes. It can be congenital (present at birth), traumatic, or due to blood vessel disease (hypertension, diabetes, strokes, aneurysms, etc). -
Quantitative Analysis of Axon Collaterals of Single Pyramidal Cells
Yang et al. BMC Neurosci (2017) 18:25 DOI 10.1186/s12868-017-0342-7 BMC Neuroscience RESEARCH ARTICLE Open Access Quantitative analysis of axon collaterals of single pyramidal cells of the anterior piriform cortex of the guinea pig Junli Yang1,2*, Gerhard Litscher1,3* , Zhongren Sun1*, Qiang Tang1, Kiyoshi Kishi2, Satoko Oda2, Masaaki Takayanagi2, Zemin Sheng1,4, Yang Liu1, Wenhai Guo1, Ting Zhang1, Lu Wang1,3, Ingrid Gaischek3, Daniela Litscher3, Irmgard Th. Lippe5 and Masaru Kuroda2 Abstract Background: The role of the piriform cortex (PC) in olfactory information processing remains largely unknown. The anterior part of the piriform cortex (APC) has been the focus of cortical-level studies of olfactory coding, and asso- ciative processes have attracted considerable attention as an important part in odor discrimination and olfactory information processing. Associational connections of pyramidal cells in the guinea pig APC were studied by direct visualization of axons stained and quantitatively analyzed by intracellular biocytin injection in vivo. Results: The observations illustrated that axon collaterals of the individual cells were widely and spatially distrib- uted within the PC, and sometimes also showed a long associational projection to the olfactory bulb (OB). The data showed that long associational axons were both rostrally and caudally directed throughout the PC, and the intrinsic associational fibers of pyramidal cells in the APC are omnidirectional connections in the PC. Within the PC, associa- tional axons typically followed rather linear trajectories and irregular bouton distributions. Quantitative data of the axon collaterals of two pyramidal cells in the APC showed that the average length of axonal collaterals was 101 mm, out of which 79 mm (78% of total length) were distributed in the PC. -
Medial Temporal Lobe (The Limbic System)
MEDIAL TEMPORAL LOBE (THE LIMBIC SYSTEM) On the medial surface of the temporal lobe are three structures critical for normal human functioning. From rostral to caudal, they are the olfactory cortex, the amygdala, and the hippocampus. We will look at the anatomy and function of each separately, although they are often grouped together as "the limbic system". A. The olfactory system: The olfactory system actually begins in the roof of the nasal cavity. The olfactory receptors are ciliated epithelial cells with an array of receptors capable of detecting thousands of different odors. However, just as with any sensory system, the receptor neurons themselves do not project to the cerebral hemispheres. Their axons project up through the cribiform plate of the skull to synapse on the dendrites of the mitral cells of the olfactory bulb. The axons of the olfactory receptors make up the elusive cranial nerve I. This fragile tract is susceptible to shearing forces in head trauma, and loss of smell is a surprisingly debilitating injury. Here is an example of a section through olfactory bulb. The olfactory bulb is not a simple relay (something which passively transmits the signal), but is a sophisticated structure in itself. The mitral cell- olfactory neuron synapse is actually within a tangle of axons and dendrites that is called a glomerulus. There is a second cell type tucked around these glomeruli which probably affects how the signal is transmitted. These cells are small and densely packed, which gives them the name "granule cells". However, they bear no relation to the granule cells of the cerebellum or cerebral cortex. -
Olfactory Maps, Circuits and Computations
Available online at www.sciencedirect.com ScienceDirect Olfactory maps, circuits and computations Andrew J Giessel and Sandeep Robert Datta Sensory information in the visual, auditory and somatosensory between local positional features to extract information systems is organized topographically, with key sensory features like object identity, depth and motion [4–6]. Unlike the ordered in space across neural sheets. Despite the existence of a small number of continuous sensory parameters that spatially stereotyped map of odor identity within the olfactory characterize vision, audition and touch (such as position, bulb, it is unclear whether the higher olfactory cortex uses frequency and amplitude), olfactory parameter space is topography to organize information about smells. Here, we poorly defined and highly multidimensional [7]. For review recent work on the anatomy, microcircuitry and example, any given monomolecular odorant can be neuromodulation of two higher-order olfactory areas: the described in terms of its functional groups, molecular piriform cortex and the olfactory tubercle. The piriform is an weight, chain length, bond substitution, resonance fre- archicortical region with an extensive local associational network quency or any number of additional chemical descrip- that constructs representations of odor identity. The olfactory tors. Furthermore, olfactory space is inherently tubercle is an extension of the ventral striatum that may use discrete — not only are individual odorants structurally reward-based learning rules to encode odor valence. We argue unique but many of the molecular descriptors typically that in contrast to brain circuits for other sensory modalities, both used for individual odorants (such as functional group or the piriform and the olfactory tubercle largely discard any bond substitution) cannot be mapped continuously in topography present in the bulb and instead use distributive any scheme for chemical space. -
Variants of Olfactory Memory and Their Dependencies on the Hippocampal Formation
The Journal of Neuroscience, February 1995, f5(2): 1162-i 171 Variants of Olfactory Memory and Their Dependencies on the Hippocampal Formation Ursula Sttiubli,’ To-Tam Le,2 and Gary Lynch* ‘Center for Neural Science, New York University, New York, New York 10003 and *Center for the Neurobiology of Learning and Memory, University of California, Irvine, California 92717 Olfactory memory in control rats and in animals with entor- pal pyramidal cells (e.g., Hjorth-Simonsen, 1972; Witter, 1993). hinal cortex lesions was tested in four paradigms: (1) a known Moreover, physiological activity in rat hippocampus becomes correct odor was present in a group of familiar but nonre- synchronized with that in the olfactory bulb and cortex during warded odors, (2) six known correct odors were simulta- odor sampling(Macrides et al., 1982). Theseobservations have neously present in a maze, (3) correct responses required prompted speculationand experimentation concerning the pos- the learning of associations between odors and objects, and sible contributions of the several stagesof the olfactory-hip- (4) six odors, each associated with a choice between two pocampal circuit to the encoding and use of memory. Lesions objects, were presented simultaneously. Control rats had no to the lateral entorhinal cortex, which separatethe hippocampus difficulty with the first problem and avoided repeating se- from its primary source of olfactory input, did not detectably lections in the second; this latter behavior resembles that affect the ability of rats to perform odor discriminations learned reported for spatial mazes but, in the present experiments, prior to surgery although they did disrupt the learning of new was not dependent upon memory for the configuration of discriminations (Staubli et al., 1984, 1986).This result suggested pertinent cues. -
Odour Discrimination Learning in the Indian Greater Short-Nosed Fruit Bat
© 2018. Published by The Company of Biologists Ltd | Journal of Experimental Biology (2018) 221, jeb175364. doi:10.1242/jeb.175364 RESEARCH ARTICLE Odour discrimination learning in the Indian greater short-nosed fruit bat (Cynopterus sphinx): differential expression of Egr-1, C-fos and PP-1 in the olfactory bulb, amygdala and hippocampus Murugan Mukilan1, Wieslaw Bogdanowicz2, Ganapathy Marimuthu3 and Koilmani Emmanuvel Rajan1,* ABSTRACT transferred directly from the olfactory bulb to the amygdala and Activity-dependent expression of immediate-early genes (IEGs) is then to the hippocampus (Wilson et al., 2004; Mouly and induced by exposure to odour. The present study was designed to Sullivan, 2010). Depending on the context, the learning investigate whether there is differential expression of IEGs (Egr-1, experience triggers neurotransmitter release (Lovinger, 2010) and C-fos) in the brain region mediating olfactory memory in the Indian activates a signalling cascade through protein kinase A (PKA), greater short-nosed fruit bat, Cynopterus sphinx. We assumed extracellular signal-regulated kinase-1/2 (ERK-1/2) (English and that differential expression of IEGs in different brain regions may Sweatt, 1997; Yoon and Seger, 2006; García-Pardo et al., 2016) and orchestrate a preference odour (PO) and aversive odour (AO) cyclic AMP-responsive element binding protein-1 (CREB-1), memory in C. sphinx. We used preferred (0.8% w/w cinnamon which is phosphorylated by ERK-1/2 (Peng et al., 2010). powder) and aversive (0.4% w/v citral) odour substances, with freshly Activated CREB-1 induces expression of immediate-early genes prepared chopped apple, to assess the behavioural response and (IEGs), such as early growth response gene-1 (Egr-1) (Cheval et al., induction of IEGs in the olfactory bulb, hippocampus and amygdala. -
Normal Mentality Associated with a Maldeveloped " Rhinencephalon " by P
J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.13.3.191 on 1 August 1950. Downloaded from J. Neurol. Neurosurg. Psychiat., 1950, 13, 191. NORMAL MENTALITY ASSOCIATED WITH A MALDEVELOPED " RHINENCEPHALON " BY P. W. NATHAN and MARION C. SMITH Fronm the Neurological Research Unit of the Medical Research Coulncil, National Hospital. Queen Square, London In 1937 Papez published his views on the Case Report functions of the gyrus fornicatus. He summarized The specimen is the brain of a man, aged 34, who died them as follows. of a chondrosarcoma of the ileum. He was one of a series of cases under investigation in a programme of " It is proposed that the hypothalamus, the anterior thalamic nuclei, the gyrus cinguli, the hippocampus, research concerned with operations for the relief of and their inter-connexions constitute a harmonious pain. As many hours had been devoted to the testing mechanism which may elaborate the functions of of sensation and the discussion of signs and symptoms, central emotion, as well as participate in emotional our knowledge of the patient, which extended over a expression." period of six months, was much greater than that Bilateral temporal lobectomies performed on acquired in most routine cases. Protected by copyright. and Bucy in 1939 gave evidence No abnormality of development had been suspected monkeys by Kiuver during the patient's life, for he came well within normal supporting Papez' general hypothesis. The effects limits from intellectual and psychological points of of extensive lesions of the hippocampus-fornix view. His mother had remained well during pregnancy, system in cats and dogs were reported by Spiegel, and his birth was normal. -
Cranial Nerves 1, 5, 7-12
Cranial Nerve I Olfactory Nerve Nerve fiber modality: Special sensory afferent Cranial Nerves 1, 5, 7-12 Function: Olfaction Remarkable features: – Peripheral processes act as sensory receptors (the other special sensory nerves have separate Warren L Felton III, MD receptors) Professor and Associate Chair of Clinical – Primary afferent neurons undergo continuous Activities, Department of Neurology replacement throughout life Associate Professor of Ophthalmology – Primary afferent neurons synapse with secondary neurons in the olfactory bulb without synapsing Chair, Division of Neuro-Ophthalmology first in the thalamus (as do all other sensory VCU School of Medicine neurons) – Pathways to cortical areas are entirely ipsilateral 1 2 Crania Nerve I Cranial Nerve I Clinical Testing Pathology Anosmia, hyposmia: loss of or impaired Frequently overlooked in neurologic olfaction examination – 1% of population, 50% of population >60 years Aromatic stimulus placed under each – Note: patients with bilateral anosmia often report nostril with the other nostril occluded, eg impaired taste (ageusia, hypogeusia), though coffee, cloves, or soap taste is normal when tested Note that noxious stimuli such as Dysosmia: disordered olfaction ammonia are not used due to concomitant – Parosmia: distorted olfaction stimulation of CN V – Olfactory hallucination: presence of perceived odor in the absence of odor Quantitative clinical tests are available: • Aura preceding complex partial seizures of eg, University of Pennsylvania Smell temporal lobe origin -
Synaptic Organization of Anterior Olfactory Nucleus Inputs to Piriform Cortex
9414 • The Journal of Neuroscience, December 2, 2020 • 40(49):9414–9425 Systems/Circuits Synaptic Organization of Anterior Olfactory Nucleus Inputs to Piriform Cortex Marco J. Russo,1 Kevin M. Franks,1 Roxanne Oghaz,1 Richard Axel,2 and Steven A. Siegelbaum3 1Department of Neuroscience, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, 2Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Department of Biochemistry and Molecular Biophysics, Howard Hughes Medical Institute, Vagelos College of Physicians & Surgeons, Columbia University, New York, New York, and 3Department of Neuroscience, Kavli Institute for Brain Science, Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Pharmacology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York Odors activate distributed ensembles of neurons within the piriform cortex, forming cortical representations of odor thought to be essential to olfactory learning and behaviors. This odor response is driven by direct input from the olfactory bulb, but is also shaped by a dense network of associative or intracortical inputs to piriform, which may enhance or constrain the cort- ical odor representation. With optogenetic techniques, it is possible to functionally isolate defined inputs to piriform cortex and assess their potential to activate or inhibit piriform pyramidal neurons. The anterior olfactory nucleus (AON) receives direct input from the olfactory bulb and sends an associative projection to piriform cortex that has potential roles in the state-dependent processing of olfactory behaviors. Here, we provide a detailed functional assessment of the AON afferents to piriform in male and female C57Bl/6J mice. We confirm that the AON forms glutamatergic excitatory synapses onto piriform pyramidal neurons; and while these inputs are not as strong as piriform recurrent collaterals, they are less constrained by disynaptic inhibition. -
On the Scent of Human Olfactory Orbitofrontal Cortex: Meta-Analysis and Comparison to Non-Human Primates
Brain Research Reviews 50 (2005) 287 – 304 www.elsevier.com/locate/brainresrev Review On the scent of human olfactory orbitofrontal cortex: Meta-analysis and comparison to non-human primates Jay A. Gottfrieda,*, David H. Zaldb aDepartment of Neurology and the Cognitive Neurology and Alzheimer’s Disease Center, Northwestern University Feinberg School of Medicine, 320 E. Superior St., Searle 11-453, Chicago, IL 60611, USA bDepartment of Psychology, Vanderbilt University, Nashville, TN 37240, USA Accepted 25 August 2005 Available online 6 October 2005 Abstract It is widely accepted that the orbitofrontal cortex (OFC) represents the main neocortical target of primary olfactory cortex. In non-human primates, the olfactory neocortex is situated along the basal surface of the caudal frontal lobes, encompassing agranular and dysgranular OFC medially and agranular insula laterally, where this latter structure wraps onto the posterior orbital surface. Direct afferent inputs arrive from most primary olfactory areas, including piriform cortex, amygdala, and entorhinal cortex, in the absence of an obligatory thalamic relay. While such findings are almost exclusively derived from animal data, recent cytoarchitectonic studies indicate a close anatomical correspondence between non-human primate and human OFC. Given this cross-species conservation of structure, it has generally been presumed that the olfactory projection area in human OFC occupies the same posterior portions of OFC as seen in non-human primates. This review questions this assumption by providing a critical survey of the localization of primate and human olfactory neocortex. Based on a meta-analysis of human functional neuroimaging studies, the region of human OFC showing the greatest olfactory responsivity appears substantially rostral and in a different cytoarchitectural area than the orbital olfactory regions as defined in the monkey.