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B-ENT 2009In combination with psychophysical testing and electrophysiological studies, magnetic resonance imaging plays a role in the clinical evaluation of patients with an... (Review)
Review
In combination with psychophysical testing and electrophysiological studies, magnetic resonance imaging plays a role in the clinical evaluation of patients with an olfactory dysfunction. Quantitative measurements of olfactory bulb volume and of olfactory sulcus depth, and the morphological depiction of structural abnormalities, make synergistic contributions to the accurate radiological diagnosis of smell dysfunction. Moreover, the plasticity of our olfactory system can be demonstrated by temporal changes in OB volumetric measurements. In this paper, we provide an outline of how to measure olfactory bulb volume and olfactory sulcus depth, with numerous illustrative cases of patients with congenital anosmia, post-infectious or posttraumatic olfactory loss and sinonasal-related olfactory dysfunction.
Topics: Humans; Islands of Calleja; Magnetic Resonance Imaging; Olfaction Disorders; Olfactory Bulb
PubMed: 20084805
DOI: No ID Found -
Nature Communications Jul 2020The learning of stimulus-outcome associations allows for predictions about the environment. Ventral striatum and dopaminergic midbrain neurons form a larger network for...
The learning of stimulus-outcome associations allows for predictions about the environment. Ventral striatum and dopaminergic midbrain neurons form a larger network for generating reward prediction signals from sensory cues. Yet, the network plasticity mechanisms to generate predictive signals in these distributed circuits have not been entirely clarified. Also, direct evidence of the underlying interregional assembly formation and information transfer is still missing. Here we show that phasic dopamine is sufficient to reinforce the distinctness of stimulus representations in the ventral striatum even in the absence of reward. Upon such reinforcement, striatal stimulus encoding gives rise to interregional assemblies that drive dopaminergic neurons during stimulus-outcome learning. These assemblies dynamically encode the predicted reward value of conditioned stimuli. Together, our data reveal that ventral striatal and midbrain reward networks form a reinforcing loop to generate reward prediction coding.
Topics: Animals; Dopamine; Dopaminergic Neurons; Male; Mesencephalon; Mice; Models, Theoretical; Olfactory Tubercle; Ventral Striatum
PubMed: 32651365
DOI: 10.1038/s41467-020-17257-7 -
Psychopharmacology Jun 1995The paw test was used to detect the preclinical profile (classical versus atypical) of five putative, atypical neuroleptics, namely olanzapine, sertindole, risperidone,...
The olfactory tubercle as a site of action of neuroleptics with an atypical profile in the paw test: effect of risperidone, prothipendyl, ORG 5222, sertindole and olanzapine.
The paw test was used to detect the preclinical profile (classical versus atypical) of five putative, atypical neuroleptics, namely olanzapine, sertindole, risperidone, prothipendyl and ORG 5222. In the paw test classical neuroleptics increase the hindlimb reaction time (HRT), a parameter with predictive validity for antipsychotic efficacy, at doses comparable to those necessary for increasing forelimb reaction time (FRT), a parameter with predictive validity for extrapyramidal side-effects, whereas atypical neuroleptics increase HRT at doses that are much smaller than those increasing FRT. All tested compounds showed the profile of atypical neuroleptics in the paw test. Using the FRT/HRT ratio of minimum effective doses as overall predictor of a favourable ratio of extrapyramidal and therapeutic effects of these drugs, the following order was found: olanzapine (20) > sertindole = risperidone = prothipendyl (10) > ORG 5222 (3). The ability of compounds to attenuate locomotor activity elicited either from the olfactory tubercle (10 micrograms dopamine: OT test) or from the nucleus accumbens (1 microgram ergometrine: ACC test) was used to establish whether the compounds preferentially act in one of these structures. Previous research has shown that classical neuroleptics are far less potent in the OT test than in the ACC test, whereas atypical neuroleptics are far more potent in the OT test than in the ACC test. All five agents preferentially acted in the olfactory tubercle. The order of potency in the olfactory tubercle was as follows: sertindole > ORG 5222 > risperidone > olanzapine > prothipendyl. It is concluded that risperidone, prothipendyl, ORG 5222, sertindole and olanzapine not only show the profile of atypical neuroleptics in the paw test, but also preferentially act in the olfactory tubercle, but not in the nucleus accumbens, viz. two features that they share with the atypical neuroleptics clozapine and thioridazine and with the putative, atypical neuroleptics raclopride and remoxipride.
Topics: Animals; Anti-Anxiety Agents; Antipsychotic Agents; Benzodiazepines; Dibenzocycloheptenes; Dibenzoxepins; Dose-Response Relationship, Drug; Heterocyclic Compounds, 4 or More Rings; Imidazoles; Indoles; Locomotion; Male; Olanzapine; Olfactory Pathways; Pirenzepine; Rats; Rats, Wistar; Risperidone; Thiazines; Time Factors
PubMed: 7480523
DOI: 10.1007/BF02245859 -
Brain Pathology (Zurich, Switzerland) Jul 2017Autism Spectrum Disorder is characterized by sensory anomalies including impaired olfactory identification. Between 5 and 46 percent of individuals with autism have a...
Autism Spectrum Disorder is characterized by sensory anomalies including impaired olfactory identification. Between 5 and 46 percent of individuals with autism have a clinical diagnosis of epilepsy. Primary olfactory cortex (piriform cortex) is central to olfactory identification and is an epileptogenic structure. Cytoarchitectural changes in olfactory cortex may underlie olfactory differences seen in autism. Primary olfactory cortex was sampled from 17 post-mortem autism cases with and without epilepsy, 11 epilepsy cases without autism and 11 typically developed cases. Stereological and neuropathological methods were used to quantify glial, pyramidal and non-pyramidal cell densities in layers of the piriform as well as identify pathological differences in this area and its neighbouring region, the olfactory tubercle. We found increased layer II glial cell densities in autism with and without epilepsy, which were negatively correlated with age and positively correlated with levels of corpora amylacea in layer I. These changes were also associated with greater symptom severity and did not extend to the olfactory tubercle. Glial cell organization may follow an altered trajectory of development with age in autism. The findings are consistent with other studies implicating increased glial cells in the autism brain. Altered cytoarchitecture may contribute to sensory deficits observed in affected individuals. This study provides evidence that autism is linked to alterations in the cytoarchitectural structure that underlies primary sensory processes and is not restricted to heteromodal ("higher") cognitive centers.
Topics: Adolescent; Adult; Age Factors; Antigens, CD; Antigens, Differentiation, Myelomonocytic; Autistic Disorder; Epilepsy; Female; Glial Fibrillary Acidic Protein; Humans; Male; Middle Aged; Neuroglia; Neurons; Olfactory Cortex; Postmortem Changes; Severity of Illness Index; Statistics as Topic; Young Adult
PubMed: 27409070
DOI: 10.1111/bpa.12415 -
Brain, Behavior and Evolution 1993The present account is a review of the main and accessory olfactory bulb projections in reptiles. From previous studies by means of the classical degeneration techniques... (Review)
Review
The present account is a review of the main and accessory olfactory bulb projections in reptiles. From previous studies by means of the classical degeneration techniques and recent studies using the autoradiographic method or the Phaseolus vulgarus-leucoagglutinin (PHA-L) tracing technique, it has become evident that, in the brain of reptiles, the vomeronasal and main olfactory systems are segregated. Moreover, the PHA-L studies have demonstrated that the main olfactory bulbs project not only to the anterior olfactory nucleus, the olfactory tubercle, and the lateral cortex, but also to the rostral portions of the external and central amygdaloid nuclei. The latter studies also provided evidence that, apart from a massive projection to the nucleus sphericus, at least in some reptilian species, the accessory olfactory bulbs project to the caudal portion of the central amygdaloid nucleus and the bed nucleus of the stria terminalis. A comparison of the olfactory projections between the various reptilian species studied revealed a considerable variation in the course of the main olfactory bulb efferents that reach the contralateral hemisphere.
Topics: Amygdala; Animals; Brain Mapping; Cerebral Cortex; Dominance, Cerebral; Lizards; Olfactory Bulb; Olfactory Pathways; Reptiles; Snakes
PubMed: 8477339
DOI: 10.1159/000113832 -
The Journal of Comparative Neurology May 1980As part of an experimental study of the ventral striatum, the horseradish peroxidase (HRP) method was used to examine the afferent and efferent neuronal connections of...
As part of an experimental study of the ventral striatum, the horseradish peroxidase (HRP) method was used to examine the afferent and efferent neuronal connections of the olfactory tubercle. Following iontophoretic applications or hydraulic injections of HRP in the tubercle, neurons labeled by retrograde transport of HRP were observed ipsilaterally in the telencephalon in the main olfactory bulb, the medial, lateral, ventral, and posterior divisions of the anterior olfactory nucleus, and in the orbital, ventral, and posterior agranular insular, primary olfactory, perirhinal, and entorhinal cortices. Labeled cells were also present in the basolateral, basomedial, anterior cortical, and posterolateral cortical amygdaloid nuclei, and bilaterally in the nucleus of the lateral olfactory tract. In the diencephalon, ipsilateral HRP-containing neurons were observed in the midline nuclei paraventricularis, parataenialis, and reuniens, and in the parafascicular intralaminar nucleus. Retrograde labeling was present in the ipsilateral brainstem in cells of the ventral tegmental area, substantia nigra, and dorsal raphe. Many of the above projections to the tubercle were found to be topographically organized. Anterograde axonal transport of HRP from the olfactory tubercle labeled terminal fields ipsilaterally in all parts of the anterior olfactory nucleus, in the ventral pallidum, and in the substantia nigra, pars reticulata. Contralaterally, terminal fields were present in the dorsal and lateral divisions of the anterior olfactory nucleus. The projections to the tubercle from the orbital, ventral, and posterior agranular insular, and perirhinal neocortices, intralaminar thalamus, and dopamine-containing areas of the ventral mesencephalon are analogous to the connections of the caudatoputamen, as are the efferents from the tubercle to the ventral globus pallidus and substantia nigra. These connections substantiate the recent suggestion that the olfactory tubercle is a striatal structure, and provide support for the ventral striatal concept. In the present study of the olfactory tubercle, and in the first study in this series on the nucleus accumbens, the ventral striatum was found to receive projections from a number of limbic system structures, including the main olfactory bulb, anterior olfactory nucleus, amygdala, hippocampus, and subiculum, and the entorhinal and primary olfactory cortices. These findings suggest that the ventral striatum is concerned with integrating limbic information into the striatal system.
Topics: Amygdala; Animals; Brain Stem; Cerebral Cortex; Corpus Striatum; Cricetinae; Dominance, Cerebral; Female; Horseradish Peroxidase; Limbic System; Male; Mesocricetus; Neural Pathways; Olfactory Bulb; Olfactory Pathways; Thalamic Nuclei
PubMed: 7410591
DOI: 10.1002/cne.901910204 -
Journal of Neurochemistry Aug 2017Recent studies show that dense dopamine (DA) innervation from the ventral tegmental area to the olfactory tubercle (OT) may play an important role in processing...
Recent studies show that dense dopamine (DA) innervation from the ventral tegmental area to the olfactory tubercle (OT) may play an important role in processing multisensory information pertaining to arousal and reward, yet little is known about DA regulation in the OT. This is mainly due to the anatomical limitations of conventional methods of determining DA dynamics in small heterogeneous OT subregions located in the ventral most part of the brain. Additionally, there is increasing awareness that anteromedial and anterolateral subregions of the OT have distinct functional roles in natural and psychostimulant drug reinforcement as well as in regulating other types of behavioral responses, such as aversion. Here, we compared extracellular DA regulation (release and clearance) in three subregions (anteromedial, anterolateral, and posterior) of the OT of urethane-anesthetized rats, using in vivo fast-scan cyclic voltammetry following electrical stimulation of ventral tegmental area dopaminergic cell bodies. The neurochemical, anatomical, and pharmacological evidence confirmed that the major electrically evoked catecholamine in the OT was DA across both its anteroposterior and mediolateral extent. While both D2 autoreceptors and DA transporters play important roles in regulating DA evoked in OT subregions, DA in the anterolateral OT was regulated less by the D2 receptors when compared to other OT subregions. Comparing previous data from other DA rich ventral striatum regions, the slow DA clearance across the OT subregions may lead to a high extracellular DA concentration and contribute towards volume transmission. These differences in DA regulation in the terminals of OT subregions and other limbic structures will help us understand the neural regulatory mechanisms of DA in the OT, which may elucidate its distinct functional contribution in the ventral striatum towards mediating aversion, reward and addiction processes.
Topics: Animals; Autoreceptors; Corpus Striatum; Dopamine; Electric Stimulation; Extracellular Space; Male; Olfactory Tubercle; Rats, Sprague-Dawley; Receptors, Dopamine D2; Reward
PubMed: 28498499
DOI: 10.1111/jnc.14069 -
Anatomical Record (Hoboken, N.J. : 2007) Sep 2013Impaired olfaction has been described as an early symptom in Alzheimer's disease (AD). Neuroanatomical changes underlying this deficit in the olfactory system are...
Impaired olfaction has been described as an early symptom in Alzheimer's disease (AD). Neuroanatomical changes underlying this deficit in the olfactory system are largely unknown. Given that interneuron populations are crucial in olfactory information processing, we have quantitatively analyzed somatostatin- (SOM), parvalbumin- (PV), and calretinin-expressing (CR) cells in the olfactory bulb, anterior olfactory nucleus, and olfactory tubercle in PS1 x APP double transgenic mice model of AD. The experiments were performed in wild type and double transgenic homozygous animal groups of 2, 4, 6, and 8 months of age to analyze early stages of the pathology. In addition, beta-amyloid (Aβ) expression and its correlation with SOM cells have been quantified under confocal microscopy. The results indicate increasing expressions of Aβ with aging as well as an early fall of SOM and CR expression, whereas PV was decreased later in the disease progression. These observations evidence an early, preferential vulnerability of SOM and CR cells in rostral olfactory structures during AD that may be useful to unravel neural basis of olfactory deficits associated to this neurodegenerative disorder.
Topics: Age Factors; Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Calbindin 2; Disease Models, Animal; Disease Progression; Female; Homozygote; Humans; Interneurons; Mice; Mice, Transgenic; Olfactory Bulb; Olfactory Pathways; Parvalbumins; Presenilin-1; Smell; Somatostatin; Time Factors
PubMed: 23904197
DOI: 10.1002/ar.22750 -
The Journal of Comparative Neurology Nov 1987The granule cell clusters in the rat olfactory tubercle were studied in Nissl-stained and Golgi-impregnated sections. Discrete cell clusters that vary in size and shape...
The granule cell clusters in the rat olfactory tubercle were studied in Nissl-stained and Golgi-impregnated sections. Discrete cell clusters that vary in size and shape occur mainly in the multiform layer and less often in the molecular layer. In cell-stained sections they consist of small, round granule cells, 5-8 microns in diameter, that often surround a core or hilar area, which may contain larger neurons. In Golgi sections, the uni- or bipolar granule cells have a globular-shaped soma and varicose dendrites that are thin, have few branches, and are usually less than 100 microns long. The dendrites remain within the border of the cluster. There are few spines on most granule cells; however, a small population of granule cells is spine-rich. The axons are beaded, seldom have collaterals, and do not appear to exit from the cluster. Either in the hilus or in among granule cells are the special large hilar neurons, whose somata measure 15-17 x 18-22 microns. Unlike most of the neurons that are near a granule cell cluster, the dendrites, and perhaps axons, of the special large hilar neurons spread throughout a cluster. Differences in their dendrites suggest that there may be several varieties of them, but not enough examples have been studied to produce a useful classification. Some of their dendrites have bushlike terminal endings. Only the initial, beaded segment of their axons has been impregnated. Three types of afferent fibers have been identified: (1) Axons that are probably afferent to the olfactory tubercle course along a granule cell cluster giving off short collaterals that end in the periphery of a cluster. (2) Axon bundles that arise mainly from medium-sized densely spined neurons in the tubercle travel through a cluster, emitting boutons en passant or short collaterals that may end on granule cells. (3) Thick axons, which are among the thickest fibers in the olfactory tubercle, enter a cluster and develop a number of collaterals that in turn divide, and finally produce a unique terminal arborization in the cluster. The granule cell clusters are frequently identified as the islands of Calleja. A comparison of the structure of granule cells with that of the cells Calleja (La Region Olfactoria del Cerebro, Madrid: N. Moya, 1893) described in the "isolates olfativos," or islands of Calleja, indicates that he was pointing to the thickened, ruffled portions of the dense cell layer and not to the granule cell clusters.(ABSTRACT TRUNCATED AT 400 WORDS)
Topics: Animals; Golgi Apparatus; Granulocytes; Neurons; Nissl Bodies; Olfactory Bulb; Rats; Rats, Inbred Strains
PubMed: 3693600
DOI: 10.1002/cne.902650102 -
The Journal of Comparative Neurology Aug 1978The catecholamine innervation of the olfactory bulb, anterior olfactory nuclei, olfactory tubercle and piriform cortex was studied in the rat using biochemical analysis...
The catecholamine innervation of the olfactory bulb, anterior olfactory nuclei, olfactory tubercle and piriform cortex was studied in the rat using biochemical analysis and fluorescence histochemistry. Biochemical studies demonstrate a moderate norepinephrine (NE) content in all olfactory structures, a high dopamine (DA) content in the olfactory tubercle and a low DA content in the olfactory bulb, anterior olfactory nucleus and piriform cortex. Following locus coeruleus lesions NE content decreases 71% in the olfactory bulb, 82% in the anterior olfactory nucleus, 62% in olfactory tubercle and 77% in piriform cortex...
Topics: Amygdala; Animals; Brain Stem; Cerebral Cortex; Corpus Striatum; Dopamine; Female; Locus Coeruleus; Medial Forebrain Bundle; Nerve Fibers; Norepinephrine; Olfactory Bulb; Olfactory Nerve; Olfactory Pathways; Rats
PubMed: 307009
DOI: 10.1002/cne.901800309