Single Cell Spike Activity in the Olfactory Bulb

1956 ◽  
Vol 186 (2) ◽  
pp. 255-257 ◽  
Author(s):  
Raymond R. Walsh
Keyword(s):  
Olfactory Bulb ◽  
Single Cell ◽  
Spike Activity ◽  
Olfactory System ◽  
Olfactory Receptors ◽  
Class I ◽  
Olfactory Stimulation ◽  
Fundamental Characteristic ◽  
Class Iii ◽  
Discharge Patterns

Studies of single-cell spike discharges in the olfactory bulb of the rabbit indicate the presence of three classes of neurons as characterized by their discharge patterns. Cells of class I discharge continuously and spontaneously; class II cells discharge intermittently in bursts, in synchrony with the passage of air through the nose. Cells of classes I and II are unmodified during olfactory stimulation. It appears there are many cells in the olfactory bulb whose discharge patterns are unrelated to excitation of the olfactory receptors by odors. Cells of class III respond to appropriate odors; the response of such cells to some odors and not others indicates that odor specificity is a fundamental characteristic of the olfactory system.

scholarly journals Reading out olfactory receptors: feedforward circuits detect odors in mixtures without demixing

2016 ◽  
Author(s):  
Alexander Mathis ◽  
Dan Rokni ◽  
Vikrant Kapoor ◽  
Matthias Bethge ◽  
Venkatesh N. Murthy
Keyword(s):  
Olfactory Bulb ◽  
Olfactory System ◽  
Olfactory Receptors ◽  
Sensory Systems ◽  
Neural Mechanisms ◽  
Small Subset ◽  
Nonlinear Interactions ◽  
Decision Boundaries ◽  
Insight Into

The olfactory system, like other sensory systems, can detect specific stimuli of interest amidst complex, varying backgrounds. To gain insight into the neural mechanisms underlying this ability, we imaged responses of mouse olfactory bulb glomeruli to single odors and hundreds of mixtures. We used this data to build a model of mixture responses that incorporated nonlinear interactions and trial-to-trial variability and explored potential decoding mechanisms that can mimic mouse performance from our previous study (Rokni et al., 2014) when given glomerular responses as input. We find that a linear decoder with sparse weights could match mouse performance using just a small subset of the glomeruli (~ 15). However, when such a decoder is trained only with single odors, it generalizes poorly to mixture stimuli due to nonlinear mixture responses. We show that mice similarly fail to generalize, although they could in principle fully decompose the mixtures. This suggests that mice learn this segregation task discriminatively by adjusting task-specific decision boundaries without taking advantage of a demixed representation of odors.

Chemometric Analysis of Substituent Effects. VIII. Alternative Interpretation of Substituent Effects (AISE)

1995 ◽  
Vol 60 (9) ◽  
pp. 1502-1528 ◽  
Author(s):  
Oldřich Pytela
Keyword(s):  
Multiple Bond ◽  
Substituent Effects ◽  
Alternative Interpretation ◽  
Class I ◽  
Reaction Centre ◽  
Correlation Equations ◽  
Class Iii ◽  
Substituent Constant ◽  
Chemical Models ◽  
The Individual

Alternative interpretation of substituent effects (AISE) starts from the presumption that a substituent only possesses a single property described by a single substituent constant. This property is transmitted to the reaction centre by three different ways depending on the interaction type in the triad reaction centre - basic skeleton - substituent. For interpretation it is substantial whether or not the substituent has p electrons at the atom adjacent to the basic skeleton. If it has none, the substituent belongs to class I and operates only by its basic effect described by the mentioned single substituent constant. Substituents of class II possess a free electron pair at the atom adjacent to the basic skeleton, and those of class III have a multiple bond between the first and the second atoms which is polarized in the direction from the basic skeleton. Substituent effects in class I are described by a substituent constant identical with σI constant. Substituents in classes II and III show additional effects proportional to the same constant. Hence, a separate treatment of substituent effects in the individual classes provides three straight lines intersecting in a common point. Mathematically, the description of substituent effects in this approach is expressed by a family of lines with a single explaining variable. The point of intersection, which is referred to as the iso-effect point, is not identical with the classic standard substituent - hydrogen - but is near to CN substituent. The approach given has the advantage of adopting a single substituent constant whose scale can be adjusted relatively precisely. Its drawback (like in the case of the correlation equations derived from the principle of separation of substituent effects) lies in a more extensive set of substituents needed for a correlation. The AISE principle has been applied to 318 series of experimental data describing effects of 32 substituents in a large variety of chemical models (aliphatic, alicyclic, aromatic, heteroaromatic, with or without direct conjugation between reaction centre and substituent) in both chemical reactions and equilibria. A comparison with two other correlation relations with two and three substituent constants for interpretation of substituent effects based on the principle of separation of the individual substituent effects showed that the closeness of AISE based correlations is comparable with that of the correlation equations currently used. It was somewhat less successful in the models with direct conjugation between reaction centre and substituent but the AISE principle can be used even in these cases.

scholarly journals Environmental Cadmium Exposure and Dental Indices in Orthodontic Patients

Healthcare ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 413
Author(s):  
Hui-Ling Chen ◽  
Jason Chen-Chieh Fang ◽  
Chia-Jung Chang ◽  
Ti-Feng Wu ◽  
I-Kuan Wang ◽  
...  
Keyword(s):  
Cadmium Concentration ◽  
Class Ii ◽  
Cadmium Exposure ◽  
Class I ◽  
P Value ◽  
Tooth Decay ◽  
Class Iii ◽  
Orthodontic Patients ◽  
Urine Cadmium ◽  
The Mean

Background. Previous studies have shown that environmental cadmium exposure could disrupt salivary gland function and is associated with dental caries and reduced bone density. Therefore, this cross-sectional study attempted to determine whether tooth decay with tooth loss following cadmium exposure is associated with some dental or skeletal traits such as malocclusions, sagittal skeletal pattern, and tooth decay. Methods. Between August 2019 and June 2020, 60 orthodontic patients with no history of previous orthodontics, functional appliances, or surgical treatment were examined. The patients were stratified into two groups according to their urine cadmium concentrations: high (>1.06 µg/g creatinine, n = 28) or low (<1.06 µg/g creatinine, n = 32). Results. The patients were 25.07 ± 4.33 years old, and most were female (female/male: 51/9 or 85%). The skeletal relationship was mainly Class I (48.3%), followed by Class II (35.0%) and Class III (16.7%). Class I molar relationships were found in 46.7% of these patients, Class II molar relationships were found in 15%, and Class III molar relationships were found in 38.3%. The mean decayed, missing, and filled surface (DMFS) score was 8.05 ± 5.54, including 2.03 ± 3.11 for the decayed index, 0.58 ± 1.17 for the missing index, and 5.52 ± 3.92 for the filled index. The mean index of complexity outcome and need (ICON) score was 53.35 ± 9.01. The facial patterns of these patients were within the average low margin (26.65 ± 5.53 for Frankfort–mandibular plane angle (FMA)). There were no significant differences in the above-mentioned dental indices between patients with high urine cadmium concentrations and those with low urine cadmium concentrations. Patients were further stratified into low (<27, n = 34), average (27–34, n = 23), and high (>34, n = 3) FMA groups. There were no statistically significant differences in the urine cadmium concentration among the three groups. Nevertheless, a marginally significant p-value of 0.05 for urine cadmium concentration was noted between patients with low FMA and patients with high FMA. Conclusion. This analysis found no association between environmental cadmium exposure and dental indices in our orthodontic patients.

scholarly journals Extinction reverses olfactory fear-conditioned increases in neuron number and glomerular size

2015 ◽  
Vol 112 (41) ◽  
pp. 12846-12851 ◽  
Author(s):  
Filomene G. Morrison ◽  
Brian G. Dias ◽  
Kerry J. Ressler
Keyword(s):  
Olfactory Bulb ◽  
Learning And Memory ◽  
Olfactory Epithelium ◽  
Olfactory System ◽  
Structural Changes ◽  
Freezing Behavior ◽  
Extinction Training ◽  
Odor Stimulus ◽  
Main Olfactory Epithelium ◽  
Odor Learning

Although much work has investigated the contribution of brain regions such as the amygdala, hippocampus, and prefrontal cortex to the processing of fear learning and memory, fewer studies have examined the role of sensory systems, in particular the olfactory system, in the detection and perception of cues involved in learning and memory. The primary sensory receptive field maps of the olfactory system are exquisitely organized and respond dynamically to cues in the environment, remaining plastic from development through adulthood. We have previously demonstrated that olfactory fear conditioning leads to increased odorant-specific receptor representation in the main olfactory epithelium and in glomeruli within the olfactory bulb. We now demonstrate that olfactory extinction training specific to the conditioned odor stimulus reverses the conditioning-associated freezing behavior and odor learning-induced structural changes in the olfactory epithelium and olfactory bulb in an odorant ligand-specific manner. These data suggest that learning-induced freezing behavior, structural alterations, and enhanced neural sensory representation can be reversed in adult mice following extinction training.

scholarly journals Region-specific amyloid-β accumulation in the olfactory system influences olfactory sensory neuronal dysfunction in 5xFAD mice

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Gowoon Son ◽  
Seung-Jun Yoo ◽  
Shinwoo Kang ◽  
Ameer Rasheed ◽  
Da Hae Jung ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Sensory Neurons ◽  
Olfactory System ◽  
Amyloid Β ◽  
Olfactory Sensory Neurons ◽  
Basal Cells ◽  
Irreversible Damage ◽  
5Xfad Mouse ◽  
Peripheral Areas ◽  
5Xfad Mice

Abstract Background Hyposmia in Alzheimer’s disease (AD) is a typical early symptom according to numerous previous clinical studies. Although amyloid-β (Aβ), which is one of the toxic factors upregulated early in AD, has been identified in many studies, even in the peripheral areas of the olfactory system, the pathology involving olfactory sensory neurons (OSNs) remains poorly understood. Methods Here, we focused on peripheral olfactory sensory neurons (OSNs) and delved deeper into the direct relationship between pathophysiological and behavioral results using odorants. We also confirmed histologically the pathological changes in 3-month-old 5xFAD mouse models, which recapitulates AD pathology. We introduced a numeric scale histologically to compare physiological phenomenon and local tissue lesions regardless of the anatomical plane. Results We observed the odorant group that the 5xFAD mice showed reduced responses to odorants. These also did not physiologically activate OSNs that propagate their axons to the ventral olfactory bulb. Interestingly, the amount of accumulated amyloid-β (Aβ) was high in the OSNs located in the olfactory epithelial ectoturbinate and the ventral olfactory bulb glomeruli. We also observed irreversible damage to the ectoturbinate of the olfactory epithelium by measuring the impaired neuronal turnover ratio from the basal cells to the matured OSNs. Conclusions Our results showed that partial and asymmetrical accumulation of Aβ coincided with physiologically and structurally damaged areas in the peripheral olfactory system, which evoked hyporeactivity to some odorants. Taken together, partial olfactory dysfunction closely associated with peripheral OSN’s loss could be a leading cause of AD-related hyposmia, a characteristic of early AD.

Mitral and Tufted Cells Differ in the Decoding Manner of Odor Maps in the Rat Olfactory Bulb

2004 ◽  
Vol 91 (6) ◽  
pp. 2532-2540 ◽  
Author(s):  
Shin Nagayama ◽  
Yuji K. Takahashi ◽  
Yoshihiro Yoshihara ◽  
Kensaku Mori
Keyword(s):  
Olfactory Bulb ◽  
Spike Activity ◽  
Homologous Series ◽  
Morphological Difference ◽  
Aliphatic Acid ◽  
Mitral Cells ◽  
Firing Rates ◽  
Aliphatic Acids ◽  
Projection Pattern ◽  
Tufted Cells

Mitral and tufted cells in the mammalian olfactory bulb are principal neurons, each type having distinct projection pattern of their dendrites and axons. The morphological difference suggests that mitral and tufted cells are functionally distinct and may process different aspects of olfactory information. To examine this possibility, we recorded odorant-evoked spike responses from mitral and middle tufted cells in the aliphatic acid- and aldehyde-responsive cluster at the dorsomedial part of the rat olfactory bulb. Homologous series of aliphatic acids and aldehydes were used for odorant stimulation. In response to adequate odorants, mitral cells showed spike responses with relatively low firing rates, whereas middle tufted cells responded with higher firing rates. Examination of the molecular receptive range (MRR) indicated that most mitral cells exhibited a robust inhibitory MRR, whereas a majority of middle tufted cells showed no or only a weak inhibitory MRR. In addition, structurally different odorants that activated neighboring clusters inhibited the spike activity of mitral cells, whereas they caused no or only a weak inhibition in the middle tufted cells. Furthermore, responses of mitral cells to an adequate excitatory odorant were greatly inhibited by mixing the odorant with other odorants that activated neighboring glomeruli. In contrast, odorants that activated neighboring glomeruli did not significantly inhibit the responses of middle tufted cells to the adequate excitatory odorant. These results indicate a clear difference between mitral and middle tufted cells in the manner of decoding the glomerular odor maps.

Reduced Efficacy of the Pipeline Embolization Device in the Treatment of Posterior Communicating Region Aneurysms with Fetal Posterior Cerebral Artery Configuration

Neurosurgery ◽  
2017 ◽  
Vol 82 (5) ◽  
pp. 695-700 ◽  
Author(s):  
Anil K Roy ◽  
Brian M Howard ◽  
Diogo C Haussen ◽  
Joshua W Osbun ◽  
Sameer H Halani ◽  
...  
Keyword(s):  
Cerebral Artery ◽  
Clinical Symptoms ◽  
Posterior Cerebral Artery ◽  
Neurological Complications ◽  
Class I ◽  
Class Iii ◽  
Pipeline Embolization Device ◽  
Independent Association ◽  
Incomplete Occlusion

Abstract BACKGROUND Aneurysms at the origin of the posterior communicating artery (PcommA) have been demonstrated to be effectively treated with the pipeline embolization device (PED). Much less is known about the efficacy of the PED for aneurysms associated with a fetal posterior cerebral artery (fPCA) variant. OBJECTIVE To study PED treatment efficacy of PcommA aneurysms, including fPCA aneurysms. METHODS A prospectively maintained university database of aneurysm patients treated with the PED was retrospectively reviewed. Demographics, treatment details, and imaging were reviewed for all PcommA and fPCA aneurysms. RESULTS Out of a total of 285 patients treated with PED, 50 patients (mean age 57.5 ± 12.2 yr, 42 females) with unruptured PcommA (9 fPCA) aneurysms were identified. Mean follow-up duration was 14.0 ± 11.6 mo (48 patients). Roy-Raymond class I occlusion on follow-up magnetic resonance or catheter angiography (mean time 11.7 ± 6.8 mo) was achieved in 30 patients (62.5%), class II occlusion in 11 patients (22.9%) and class III occlusion in 7 patients (14.5%). The PcommA was occluded in 56% of patients without any clinical symptoms. No deaths or permanent neurological complications occurred. In fPCA aneurysms, class I occlusion was seen in 1 patient, class 2 occlusion in 2 patients, and class III occlusion in 6 patients. Multivariate analysis revealed an independent association between incomplete occlusion and fPCA configuration (OR 73.65; 95% CI: 5.84-929.13; P = .001). CONCLUSION The PED is a safe and effective treatment for PcommA aneurysms, although fetal anatomy should increase consideration of traditional endovascular techniques or surgical clipping.

Effects of antiarrhythmic drugs on atrioventricular conduction in patients with preexisting bundle branch block

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
S Kochav ◽  
R.C Chen ◽  
J.M.D Dizon ◽  
J.A.R Reiffel
Keyword(s):  
Proportional Hazards ◽  
Cox Proportional Hazards ◽  
Class I ◽  
Class Iii ◽  
Bundle Branch Block ◽  
Kaplan Meier ◽  
Cox Proportional Hazards Models ◽  
Hazard Ratios ◽  
History Of ◽  
Propensity Score Stratification

Abstract Background Theoretical concern exists regarding AV block (AVB) with class I antiarrhythmics (AADs) when bundle branch block (BBB) is present. Whether this is substantiated in real-world populations is unknown. Purpose To determine the relationship between type of AAD and incidence of AVB in patients with preexisting BBB. Methods We retrospectively studied all patients with BBB who received class I and III AADs between 1997–2019 to compare incidence of AVB. We defined index time as first exposure to either drug class and excluded patients with prior AVB or exposed to both classes. Time-at-risk window ended at first outcome occurrence or when patients were no longer observed in the database. We estimated hazard ratios for incident AVB using Cox proportional hazards models with propensity score stratification, adjusting for over 32,000 covariates from the electronic health record. Kaplan-Meier methods were used to determine treatment effects over time. Results Of 40,120 individuals with BBB, 148 were exposed to a class I AAD and 2401 to a class III AAD. Over nearly 4,200 person-years of follow up, there were 22 and 620 outcome events in the class I and class III cohorts, respectively (Figure). In adjusted analyses, AVB risk was markedly lower in patients exposed to class I AADs compared with class III (HR 0.48 [95% CI 0.30–0.75]). Conclusion Among patients with BBB, exposure to class III AADs was strongly associated with greater risk of incident AVB. This likely reflects differences in natural history of patients receiving class I vs class III AADs rather than adverse class III effects, however, the lack of worse outcomes acutely with class I AADs suggests that they may be safer in BBB than suspected. Funding Acknowledgement Type of funding source: None

scholarly journals SATELLITE DNAs IN THE EMBRYOS OF VARIOUS SPECIES OF THE GENUS DROSOPHILA

Genetics ◽  
1972 ◽  
Vol 72 (3) ◽  
pp. 431-439
Author(s):  
E C Travaglini ◽  
J Petrovic ◽  
J Schultz
Keyword(s):  
Buoyant Density ◽  
Gc Content ◽  
Drosophila Species ◽  
Class I ◽  
Evolutionary Divergence ◽  
Dna Molecules ◽  
Class Iii ◽  
Satellite Dnas ◽  
Evolutionary Pattern ◽  
Gc Composition

ABSTRACT A tentative evolutionary pattern has been found for two classes of the multiple satellite DNA's found in the genus Drosophila. The satellite DNA's from five Drosophila species (D. melanogaster, D. simulans, D. nasuta, D. virilis and D. hydei) were analyzed and found to fall into three arbitrary CsCl buoyant density classes: Class I, ρ = 1.661-1.669 g cm-3, DNA molecules composed of primarily dA and dT moieties; Class II, ρ = 1.685 and ρ = 1.692, DNA molecules of low GC content; and Class III, ρ = 1.711, a DNA of high GC composition. The dAT satellite DNA's appear in all the species studied except D. hydei, the species of most recent evolutionary divergence, whereas the heavy satellite appears only in the two species of most recent divergence, D. virilis and D. hydei.

scholarly journals Duration of the Pubertal Peak in Skeletal Class I and Class III Subjects

2010 ◽  
Vol 80 (1) ◽  
pp. 54-57 ◽  
Author(s):  
Małgorzata Kuc-Michalska ◽  
Tiziano Baccetti
Keyword(s):  
Class I ◽  
Class Iii ◽  
Skeletal Class
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