scholarly journals Dynamics of Olfactory Bulb Input and Output Activity During Odor Stimulation in Zebrafish

2004 ◽  
Vol 91 (6) ◽  
pp. 2658-2669 ◽  
Author(s):  
Rainer W. Friedrich ◽  
Gilles Laurent
Keyword(s):  
Olfactory Bulb ◽  
Activity Patterns ◽  
Odor Identification ◽  
Population Activity ◽  
Excitatory Response ◽  
Input And Output ◽  
Response Onset ◽  
Output Neurons ◽  
Response Profiles ◽  
Over Time

The processing of odor-evoked activity in the olfactory bulb (OB) of zebrafish was studied by extracellular single unit recordings from the input and output neurons, i.e., olfactory receptor neurons (ORNs) and mitral cells (MCs), respectively. A panel of 16 natural amino acid odors was used as stimuli. Responses of MCs, but not ORNs, changed profoundly during the first few hundred milliseconds after response onset. In MCs, but not ORNs, the total evoked excitatory activity in the population was initially odordependent but subsequently converged to a common level. Hence, the overall population activity is regulated by network interactions in the OB. The tuning widths of both ORN and MC response profiles were similar and, on average, stable over time. However, when analyzed for individual neurons, MC response profiles could sharpen (excitatory response to fewer odors) or broaden (excitatory response to more odors), whereas ORN response profiles remained nearly unchanged. Several observations indicate that dynamic inhibition plays an important role in this remodeling. Finally, the reliability of odor identification based on MC population activity patterns improved over time, whereas odor identification based on ORN activity patterns was most reliable early in the odor response. These results demonstrate that several properties of MC, but not ORN, activity change during the initial phase of the odor response with important consequences for odor-encoding activity patterns. Furthermore, our data indicate that inhibitory interactions in the OB are important in dynamically shaping the activity of OB output neurons.

scholarly journals Representational drift in the mouse visual cortex

2020 ◽  
Author(s):  
Daniel Deitch ◽  
Alon Rubin ◽  
Yaniv Ziv
Keyword(s):  
Large Scale ◽  
Activity Patterns ◽  
Population Level ◽  
Population Activity ◽  
Cortical Areas ◽  
Electrophysiological Recordings ◽  
The Face ◽  
Visual Cortical ◽  
Mouse Visual Cortex ◽  
Over Time

AbstractNeuronal representations in the hippocampus and related structures gradually change over time despite no changes in the environment or behavior. The extent to which such ‘representational drift’ occurs in sensory cortical areas and whether the hierarchy of information flow across areas affects neural-code stability have remained elusive. Here, we address these questions by analyzing large-scale optical and electrophysiological recordings from six visual cortical areas in behaving mice that were repeatedly presented with the same natural movies. We found representational drift over timescales spanning minutes to days across multiple visual areas. The drift was driven mostly by changes in individual cells’ activity rates, while their tuning changed to a lesser extent. Despite these changes, the structure of relationships between the population activity patterns remained stable and stereotypic, allowing robust maintenance of information over time. Such population-level organization may underlie stable visual perception in the face of continuous changes in neuronal responses.

scholarly journals Changes in weak pair-wise correlations during running reshapes network state in the main olfactory bulb

2020 ◽  
Author(s):  
Udaysankar Chockanathan ◽  
Emily J. W. Crosier ◽  
Spencer Waddle ◽  
Edward Lyman ◽  
Richard C. Gerkin ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Spontaneous Activity ◽  
Olfactory System ◽  
Activity Patterns ◽  
Higher Order ◽  
High Density ◽  
Main Olfactory Bulb ◽  
Population Activity ◽  
Maximum Entropy Models ◽  
Electrophysiological Recordings

AbstractNeural codes for sensory representations are thought to reside in a broader space defined by the patterns of spontaneous activity that occur when stimuli are not being presented. To understand the structure of this spontaneous activity in the olfactory system, we performed high-density recordings of population activity in the main olfactory bulb of awake mice. We found that spontaneous activity patterns of ensembles of mitral and tufted (M/T) cells in the main olfactory bulb changed dramatically during locomotion, including decreases in pairwise correlations between neurons and increases in the entropy of the population. Maximum entropy models of the ensemble activity revealed that pair-wise interactions were better at predicting patterns of activity when the animal was stationary than while running, suggesting that higher order (3rd, 4th order) interactions between neurons shape activity during locomotion. Taken together, we found that locomotion influenced the structure of spontaneous population activity at the earliest stages of olfactory processing, 1 synapse away from the sensory receptors in the nasal epithelium.New and NoteworthyThe organization and structure of spontaneous population activity in the olfactory system places constraints of how odor information is represented. Using high-density electrophysiological recordings of mitral and tufted cells, we found that running increases the dimensionality of spontaneous activity, implicating higher-order interactions among neurons during locomotion. Behavior thus flexibly alters neuronal activity at the earliest stages of sensory processing.

Change of olfactory function as a marker of inflammatory activity and disability progression in MS

2017 ◽  
Vol 25 (2) ◽  
pp. 267-274 ◽  
Author(s):  
Gabriel Bsteh ◽  
Harald Hegen ◽  
Felix Ladstätter ◽  
Klaus Berek ◽  
Matthias Amprosi ◽  
...  
Keyword(s):  
Multivariate Model ◽  
Olfactory Dysfunction ◽  
Olfactory Function ◽  
Odor Identification ◽  
Olfactory Threshold ◽  
Disability Progression ◽  
Increased Risk ◽  
Changes Over Time ◽  
Over Time ◽  
Risk Of Relapse

Background: Impaired olfactory threshold has been reported in early inflammatory phases of MS, while impaired odor identification was associated with more widespread disability. Objective: To prospectively assess the development of olfactory function and its correlation with relapse and disability progression. Methods: In this prospective, 3-year longitudinal study on 151 MS patients and 30 healthy controls, three different qualities of olfactory function (threshold, discrimination, and identification) were quantified using the Sniffin’ Sticks test. The influence of relapses and disability on olfactory function was analyzed at different time points and in a multivariate model. Results: Discrimination and identification capability significantly worsened over 3 years, while threshold did not. Threshold was markedly impaired in patients with relapse activity within 12 months, recovered in the absence of relapse, and was associated with a 2.5-fold increased risk of relapse. Deterioration of discrimination and identification was irreversible and both strongly associated with and predictive of EDSS progression. Conclusion: Olfactory function changes over time in MS. Threshold impairment is transient and predicts inflammatory disease activity, while odor identification and discrimination are associated with disability progression. Olfactory dysfunction might be a useful and easily obtainable parameter to monitor patients with regard to inflammation and neurodegeneration in MS.

scholarly journals Differential impacts of repeated sampling on odor representations by genetically-defined mitral and tufted cell subpopulations in the mouse olfactory bulb

2020 ◽  
Author(s):  
Thomas P. Eiting ◽  
Matt Wachowiak
Keyword(s):  
Information Processing ◽  
Olfactory Bulb ◽  
High Frequency ◽  
Response Patterns ◽  
Repeated Sampling ◽  
Tufted Cell ◽  
Cell Subpopulations ◽  
Genetic Targeting ◽  
The Impact ◽  
Over Time

AbstractSniffing—the active control of breathing beyond passive respiration—is used by mammals to modulate olfactory sampling. Sniffing allows animals to make odor-guided decisions within ~200 ms, but animals routinely engage in bouts of high-frequency sniffing spanning several seconds; the impact of such repeated odorant sampling on odor representations remains unclear. We investigated this question in the mouse olfactory bulb, where mitral and tufted cells (MTCs) form parallel output streams of odor information processing. To test the impact of repeated odorant sampling on MTC responses, we used two-photon imaging in anesthetized male and female mice to record activation of MTCs while precisely varying inhalation frequency. A combination of genetic targeting and viral expression of GCaMP6 reporters allowed us to access mitral (MC) and superficial tufted cell (sTC) subpopulations separately. We found that repeated odorant sampling differentially affected responses in MCs and sTCs, with MCs showing more diversity than sTCs over the same time period. Impacts of repeated sampling among MCs included both increases and decreases in excitation, as well as changes in response polarity. Response patterns across ensembles of simultaneously-imaged MCs reformatted over time, with representations of different odorants becoming more distinct. MCs also responded differentially to changes in inhalation frequency, whereas sTC responses were more uniform over time and across frequency. Our results support the idea that MCs and TCs comprise functionally distinct pathways for odor information processing, and suggest that the reformatting of MC odor representations by high-frequency sniffing may serve to enhance the discrimination of similar odors.

Population activity patterns ? St. Louis study

1982 ◽  
Vol 2 (1-2) ◽  
pp. 197-212 ◽  
Author(s):  
Michael D. Koontz ◽  
John P. Robinson
Keyword(s):  
Activity Patterns ◽  
Population Activity

Abstract P274: Physical Activity Patterns and Determinants Following Acute Myocardial Infarction: Insights From the VIRGO Study (Variation in Recovery: Role of Gender on Outcomes of Young Acute Myocardial Infarction Patients)

Circulation ◽  
2015 ◽  
Vol 131 (suppl_1) ◽  
Author(s):  
Karl E Minges ◽  
Kelly M Strait ◽  
Sarah Camhi ◽  
Judith H Lichtman ◽  
Rachel P Dreyer ◽  
...  
Keyword(s):  
Physical Activity ◽  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Activity Patterns ◽  
Estimating Equation ◽  
Vigorous Activity ◽  
Targeted Interventions ◽  
Factors Associated ◽  
Wide Range ◽  
Over Time

Introduction: Despite the benefits of participation in regular physical activity (PA) following acute myocardial infarction (AMI), little is known about the habitual patterns of PA for young AMI patients, especially expanding beyond findings for those engaged in cardiac rehabilitation. We assessed patterns and determinants in levels of PA over a period of 12-months following AMI. Methods: A 2:1 (women:men) observational study design enrolled 3,572 AMI patients (2,397 women, 67.1%) aged 18-55 years from 103 US, 24 Spanish, and 3 Australian hospitals (2008-2012). Data were obtained by medical record abstraction and patient interviews at baseline (pre-AMI), 1- and 12-months post-AMI. Patients were assigned to AHA defined levels of PA based on self-reported frequency, duration, and intensity, as follows: Active (≥ 150 min/wk moderate or ≥ 75 min/wk vigorous activity), Insufficient (10-149 min/wk moderate or 10-74 min/wk vigorous activity), or Inactive (< 10 min/wk moderate or vigorous activity). We used a generalized estimating equation model to examine the factors associated with insufficient/inactive PA levels over time. Results: At baseline, 1- and 12-months post-AMI, 36.7%, 37.6%, and 40.0% of patients were considered active. There were 27 PA patterns observed from baseline to 12-months (Table). The most frequent were those with no change in PA over time (14% staying active, 7% insufficient, and 13% inactive). Additionally, 25% of patients had an increase (at least a one category change) in PA, while 19% had a decrease between baseline and 12-months post-AMI. Female sex, non-white race, non-active workplaces, smoking, diabetes, hypertension, and obesity were independently associated with being insufficient/inactive over time (all p<.05). Conclusions: Despite clinical recommendations, young adults recovering from AMI experience a wide range of PA patterns. By identifying factors associated with insufficient/inactive PA during recovery, targeted interventions can be introduced prior to hospital discharge.

Abstract P164: Seasonal patterns of mortality from cardiovascular diseases in Panama.

Circulation ◽  
2012 ◽  
Vol 125 (suppl_10) ◽  
Author(s):  
Jorge A Motta ◽  
Carlos Gordon ◽  
Beatriz Gomez ◽  
Eva Castillo ◽  
Hugo Herrera-Ballesteros
Keyword(s):  
Seasonal Pattern ◽  
Activity Patterns ◽  
Seasonal Patterns ◽  
Seasonal Cycles ◽  
Population Activity ◽  
Diabetes Mortality ◽  
Weather Changes ◽  
External Causes ◽  
Cv Disease ◽  
Seasonal Index

Seasonal patterns of cardiovascular (CV) mortality have been reported in many regions of the world, but mostly in temperate zones. These cycles and seasonal patterns of mortality have been identified by looking at mortality rate series over extended periods of time and by filtering its stochastic components. The reasons for these variations have been attributed to multiple causes. Empirical observations by health care worker have suggested that in Panama there are seasonal changes of CV disease mortality but this phenomenon had not been studied. The speculation is that this may be related to variation in the incidence of respiratory diseases, weather changes or to population activity patterns associated with holidays. Our hypothesis for this study is that in Panama mortality related to CV disease has a seasonal pattern. We compiled from the National Registry of Mortality all deaths that occurred in the country from cardiovascular diseases (n=36,145) and diabetes (n=7,076) for the years 2001–2009. A monthly time series of mortality was calculated and its components were decomposed utilizing moving averages. Elements, like cycle, seasonal occurrence and stochastic components, were separated. We also developed a seasonal index of mortality for these diseases. For the same years, we performed a similar analysis for all deaths attributed to cancer and external causes. Analysis of these mortality series revealed seasonal cycles for total cardiovascular mortality and diabetes mortality. Death from cancer and external causes also showed seasonal cycles. CV mortality and diabetes mortality peaked at the beginning of the third trimester of the year and were lowest during the first trimester. For the month of July, the CV mortality seasonal index showed a score of 108, and an average number of CV deaths of 364. The lowest seasonal index score for CV mortality was 87 in February, with an average number of CV deaths of 296. The cycles observed for cancer and deaths from external causes did not match the cycles observed for CV diseases and diabetes. We conclude that there is a seasonal pattern of CV mortality in Panama. The drivers of these cyclical changes of CV mortality have not yet been identified, but we are evaluating the relationship of acute respiratory illnesses, population activity patterns and weather changes to these seasonal mortality variations.

Olfactory bulb responses to odor stimulation: analysis of response pattern and intensity relationships

1986 ◽  
Vol 56 (6) ◽  
pp. 1571-1589 ◽  
Author(s):  
T. A. Harrison ◽  
J. W. Scott
Keyword(s):  
Olfactory Bulb ◽  
Stimulus Intensity ◽  
Plexiform Layer ◽  
Response Assessment ◽  
Spike Trains ◽  
Response Magnitude ◽  
Response Form ◽  
Stimulus Response ◽  
Response Profiles ◽  
Inhibitory Components

Extracellular recordings were made from mitral cells, tufted cells, and presumed glomerular layer and external plexiform layer interneurons of the olfactory bulb of anesthetized rats during odor stimulation. Intensity responses of these cells were studied by presenting a series of six or seven concentrations, spanning a range greater than two log units, in a cyclic artificial sniff paradigm, which produced repeated response measures at each concentration. Experiments focused on obtaining a complete intensity series, including interspersed unstimulated spontaneous activity records, for a single odorant (usually amyl acetate), but concentration responses to other odorants were tested when possible. Odor responses of 46 cells were studied with two approaches. Response form was examined in an attempt to define response classes based on qualitative characteristics of the temporal pattern of response. Assessment of response magnitude was attempted, in order to construct stimulus-response functions for each cell, independent of response form. As previously reported for olfactory bulb cells, the cells in our sample responded to odor stimulation with spike trains of a variety of temporal patterns, consisting of excitatory and inhibitory components that were frequently recognizable in the responses of a cell across a range of concentrations. However, response patterns usually changed significantly with concentration, such that response form across the concentration range could not be predicted from the response at any one concentration. Responses of different cells were sometimes similar to each other in form at one concentration and quite different from each other in the rest of their concentration-response profiles. Classification of response profiles into discrete types, based on consistency of response form throughout the profile, was therefore not feasible. In agreement with other reports, response of a single cell to different odorants sometimes showed similar forms and sometimes showed very different forms across the concentration-response profiles. Since the response form depends on the stimulus intensity as well as the stimulus quality, characterization of response magnitude and of the pattern of response to different odors require testing with a series of stimulus concentrations. Because odor responses consisted of temporally patterned spike trains, whose components changed in complex ways with stimulus intensity, it was not possible to quantify response magnitude by measuring characteristics of particular response components or counting mean frequency.(ABSTRACT TRUNCATED AT 400 WORDS)

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