Dynamic reconfiguration of brain stem neural assemblies: respiratory phase-dependent synchrony versus modulation of firing rates

1992 ◽  
Vol 67 (4) ◽  
pp. 923-930 ◽  
Author(s):  
B. G. Lindsey ◽  
Y. M. Hernandez ◽  
K. F. Morris ◽  
R. Shannon ◽  
G. L. Gerstein
Keyword(s):  
Brain Stem ◽  
Temporal Variations ◽  
Data Sets ◽  
Firing Rates ◽  
Neural Assemblies ◽  
Cross Correlation Analysis ◽  
Respiratory Phase ◽  
Sequential Samples ◽  
Spike Train Data ◽  
Respiratory Phases

1. The objective of this work was to determine whether configurations of midline brain stem neural assemblies change during the respiratory cycle. 2. Spike trains of several single neurons were recorded simultaneously in anesthetized, paralyzed, bilaterally vagotomized, artificially ventilated cats. Data were analyzed with cross-correlational and gravity methods. 3. Sequential samples from each of eight groups of neurons known to contain synchronously discharging neurons exhibited temporal variations in that synchrony. 4. Gravity analysis of short (less than 200-s) samples of spike train data revealed 20 pairs of clustered particles that were not predicted from cross-correlation analysis of the parent data sets (greater than 20 min). 5. Twenty-nine groups of three to eight simultaneously monitored neurons, each with at least two synchronously discharging neurons, were analyzed for evidence of respiratory phase-dependent modulation of that coordinated activity. Spikes from successive interleaved inspiratory and expiratory intervals were analyzed separately. 6. Neurons pairs in 11 groups were more synchronous during the inspiratory interval; six groups had pairs that were more synchronous during the expiratory period. In two groups, different pairs were synchronous in different respiratory phases. In 11 of the 26 pairs that exhibited phase-dependent differences in synchrony, neither neuron had a respiratory-modulated firing rate as judged by either the cycle-triggered histogram or an analysis of variance of their firing rates. 7. Configurations of respiratory-related brain stem neural networks changed with time and the phases of breathing. Neurons with no apparent respiratory modulation of their individual firing rates collectively exhibited respiratory phase-dependent modulation of their impulse synchrony.(ABSTRACT TRUNCATED AT 250 WORDS)

Repeated Sequences of Interspike Intervals in Baroresponsive Respiratory Related Neuronal Assemblies of the Cat Brain Stem

2000 ◽  
Vol 84 (3) ◽  
pp. 1136-1148 ◽  
Author(s):  
E. Y. Chang ◽  
K. F. Morris ◽  
R. Shannon ◽  
B. G. Lindsey
Keyword(s):  
Brain Stem ◽  
Nucleus Tractus Solitarius ◽  
Spike Trains ◽  
Short Time Scale ◽  
Data Sets ◽  
Firing Rates ◽  
Neuronal Assemblies ◽  
Cross Correlation Analysis ◽  
Single Spike ◽  
Adult Cats

Many neurons exhibit spontaneous activity in the absence of any specific experimental perturbation. Patterns of distributed synchrony embedded in such activity have been detected in the brain stem, suggesting that it represents more than “baseline” firing rates subject only to being regulated up or down. This work tested the hypothesis that nonrandom sequences of impulses recur in baroresponsive respiratory-related brain stem neurons that are elements of correlational neuronal assemblies. In 15 Dial-urethan anesthetized vagotomized adult cats, neuronal impulses were monitored with microelectrode arrays in the ventral respiratory group, nucleus tractus solitarius, and medullary raphe nuclei. Efferent phrenic nerve activity was recorded. Spike trains were analyzed with cycle-triggered histograms and tested for respiratory-modulated firing rates. Baroreceptors were stimulated by unilateral pressure changes in the carotid sinus or occlusion of the descending aorta; changes in firing rates were assessed with peristimulus time and cumulative sum histograms. Cross-correlation analysis was used to test for nonrandom temporal relationships between spike trains. Favored patterns of interspike interval sequences were detected in 31 of 58 single spike trains; 18 of the neurons with significant sequences also had short-time scale correlations with other simultaneously recorded cells. The number of distributed patterns exceeded that expected under the null hypothesis in 12 of 14 data sets composed of 4–11 simultaneously recorded spike trains. The data support the hypothesis that baroresponsive brain stem neurons operate in transiently configured coordinated assemblies and suggest that single neuron patterns may be fragments of distributed impulse sequences. The results further encourage the search for coding functions of spike patterns in the respiratory network.

scholarly journals Temporal Variations in Patterns of Clostridioides difficile Strain Diversity and Antibiotic Resistance in Thailand

Antibiotics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 714
Author(s):  
Supapit Wongkuna ◽  
Tavan Janvilisri ◽  
Matthew Phanchana ◽  
Phurt Harnvoravongchai ◽  
Amornrat Aroonnual ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Antimicrobial Susceptibility ◽  
Reference Strain ◽  
Toxin Production ◽  
Temporal Variations ◽  
Toxin Gene ◽  
Data Sets ◽  
Clostridioides Difficile ◽  
Life Threatening ◽  
Susceptibility Profiles

Clostridioides difficile has been recognized as a life-threatening pathogen that causes enteric diseases, including antibiotic-associated diarrhea and pseudomembranous colitis. The severity of C. difficile infection (CDI) correlates with toxin production and antibiotic resistance of C. difficile. In Thailand, the data addressing ribotypes, toxigenic, and antimicrobial susceptibility profiles of this pathogen are scarce and some of these data sets are limited. In this study, two groups of C. difficile isolates in Thailand, including 50 isolates collected from 2006 to 2009 (THA group) and 26 isolates collected from 2010 to 2012 (THB group), were compared for toxin genes and ribotyping profiles. The production of toxins A and B were determined on the basis of toxin gene profiles. In addition, minimum inhibitory concentration of eight antibiotics were examined for all 76 C. difficile isolates. The isolates of the THA group were categorized into 27 A−B+CDT− (54%) and 23 A-B-CDT- (46%), while the THB isolates were classified into five toxigenic profiles, including six A+B+CDT+ (23%), two A+B+CDT− (8%), five A−B+CDT+ (19%), seven A−B+CDT− (27%), and six A−B−CDT− (23%). By visually comparing them to the references, only five ribotypes were identified among THA isolates, while 15 ribotypes were identified within THB isolates. Ribotype 017 was the most common in both groups. Interestingly, 18 unknown ribotyping patterns were identified. Among eight tcdA-positive isolates, three isolates showed significantly greater levels of toxin A than the reference strain. The levels of toxin B in 3 of 47 tcdB-positive isolates were significantly higher than that of the reference strain. Based on the antimicrobial susceptibility test, metronidazole showed potent efficiency against most isolates in both groups. However, high MIC values of cefoxitin (MICs 256 μg/mL) and chloramphenicol (MICs ≥ 64 μg/mL) were observed with most of the isolates. The other five antibiotics exhibited diverse MIC values among two groups of isolates. This work provides evidence of temporal changes in both C. difficile strains and patterns of antimicrobial resistance in Thailand.

scholarly journals Multimodal Medullary Neurons and Correlational Linkages of the Respiratory Network

1999 ◽  
Vol 82 (1) ◽  
pp. 188-201 ◽  
Author(s):  
Zhongzeng Li ◽  
Kendall F. Morris ◽  
David M. Baekey ◽  
Roger Shannon ◽  
Bruce G. Lindsey
Keyword(s):  
Firing Rate ◽  
Nucleus Tractus Solitarius ◽  
Motor Pattern ◽  
Sensory Modality ◽  
Spike Trains ◽  
Negative Feedback Regulation ◽  
Firing Rates ◽  
Respiratory Network ◽  
Cross Correlation Analysis ◽  
Stimulation Of

This study addresses the hypothesis that multiple sensory systems, each capable of reflexly altering breathing, jointly influence neurons of the brain stem respiratory network. Carotid chemoreceptors, baroreceptors, and foot pad nociceptors were stimulated sequentially in 33 Dial-urethan–anesthetized or decerebrate vagotomized adult cats. Neuronal impulses were monitored with microelectrode arrays in the rostral and caudal ventral respiratory group (VRG), nucleus tractus solitarius (NTS), and n. raphe obscurus. Efferent phrenic nerve activity was recorded. Spike trains of 889 neurons were analyzed with cycle-triggered histograms and tested for respiratory-modulated firing rates. Responses to stimulus protocols were assessed with peristimulus time and cumulative sum histograms. Cross-correlation analysis was used to test for nonrandom temporal relationships between spike trains. Spike-triggered averages of efferent phrenic activity and antidromic stimulation methods provided evidence for functional associations of bulbar neurons with phrenic motoneurons. Spike train cross-correlograms were calculated for 6,471 pairs of neurons. Significant correlogram features were detected for 425 pairs, including 189 primary central peaks or troughs, 156 offset peaks or troughs, and 80 pairs with multiple peaks and troughs. The results provide evidence that correlational medullary assemblies include neurons with overlapping memberships in groups responsive to different sets of sensory modalities. The data suggest and support several hypotheses concerning cooperative relationships that modulate the respiratory motor pattern. 1) Neurons responsive to a single tested modality promote or limit changes in firing rate of multimodal target neurons. 2) Multimodal neurons contribute to changes in firing rate of neurons responsive to a single tested modality. 3) Multimodal neurons may promote responses during stimulation of one modality and “limit” changes in firing rates during stimulation of another sensory modality. 4) Caudal VRG inspiratory neurons have inhibitory connections that provide negative feedback regulation of inspiratory drive and phase duration.

scholarly journals Inferring information flow in spike-train data sets using a trial-shuffle method

PLoS ONE ◽  
2018 ◽  
Vol 13 (11) ◽  
pp. e0206977 ◽  
Author(s):  
Benjamin L. Walker ◽  
Katherine A. Newhall
Keyword(s):  
Spike Train ◽  
Information Flow ◽  
Data Sets ◽  
Spike Train Data

scholarly journals SuperDARN convection and Sondrestrom plasma drift

2001 ◽  
Vol 19 (7) ◽  
pp. 749-759 ◽  
Author(s):  
L. Xu ◽  
A. V. Koustov ◽  
J. Thayer ◽  
M. A. McCready
Keyword(s):  
Reasonable Agreement ◽  
Temporal Variations ◽  
Line Of Sight ◽  
Data Sets ◽  
Plasma Convection ◽  
Map Comparison ◽  
Incoherent Scatter ◽  
Plasma Drift ◽  
End Products ◽  
Strong Disagreement

Abstract. Plasma convection measurements by the Goose Bay and Stokkseyri SuperDARN radar pair and the Sondrestrom incoherent scatter radar are compared in three different ways, by looking at the line-of-sight (l-o-s) velocities, by comparing the SuperDARN vectors and corresponding Sondrestrom l-o-s velocities and by comparing the end products of the instruments, the convection maps. All three comparisons show overall reasonable agreement of the convection measurements though the data spread is significant and for some points a strong disagreement is obvious. The convection map comparison shows a tendency for the SuperDARN velocities to be often less than the Sondrestrom drifts for strong flows (velocities > 1000 m/s) and larger for weak flows (velocities < 500 m/s). On average, both effects do not exceed 35%. Data indicate that inconsistencies between the two data sets occur largely at times of fast temporal variations of the plasma drift and for strongly irregular flow ac-cording to the SuperDARN convection maps. These facts indicate that the observed discrepancies are in many cases a result of the different spatial and temporal resolutions of the instruments.Key words. Ionosphere (ionospheric irregularities; plasma convection; polar ionosphere)

scholarly journals Evaluation of multiple forcing data sets for precipitation and shortwave radiation over major land areas of China

2017 ◽  
Vol 21 (11) ◽  
pp. 5805-5821 ◽  
Author(s):  
Fan Yang ◽  
Hui Lu ◽  
Kun Yang ◽  
Jie He ◽  
Wei Wang ◽  
...  
Keyword(s):  
Time Series ◽  
Temporal Variations ◽  
Spatiotemporal Variability ◽  
Shortwave Radiation ◽  
Data Sets ◽  
Precipitation Data ◽  
Land Data Assimilation ◽  
Land Data Assimilation System ◽  
Data Assimilation System ◽  
Assimilation System

Abstract. Precipitation and shortwave radiation play important roles in climatic, hydrological and biogeochemical cycles. Several global and regional forcing data sets currently provide historical estimates of these two variables over China, including the Global Land Data Assimilation System (GLDAS), the China Meteorological Administration (CMA) Land Data Assimilation System (CLDAS) and the China Meteorological Forcing Dataset (CMFD). The CN05.1 precipitation data set, a gridded analysis based on CMA gauge observations, also provides high-resolution historical precipitation data for China. In this study, we present an intercomparison of precipitation and shortwave radiation data from CN05.1, CMFD, CLDAS and GLDAS during 2008–2014. We also validate all four data sets against independent ground station observations. All four forcing data sets capture the spatial distribution of precipitation over major land areas of China, although CLDAS indicates smaller annual-mean precipitation amounts than CN05.1, CMFD or GLDAS. Time series of precipitation anomalies are largely consistent among the data sets, except for a sudden decrease in CMFD after August 2014. All forcing data indicate greater temporal variations relative to the mean in dry regions than in wet regions. Validation against independent precipitation observations provided by the Ministry of Water Resources (MWR) in the middle and lower reaches of the Yangtze River indicates that CLDAS provides the most realistic estimates of spatiotemporal variability in precipitation in this region. CMFD also performs well with respect to annual mean precipitation, while GLDAS fails to accurately capture much of the spatiotemporal variability and CN05.1 contains significant high biases relative to the MWR observations. Estimates of shortwave radiation from CMFD are largely consistent with station observations, while CLDAS and GLDAS greatly overestimate shortwave radiation. All three forcing data sets capture the key features of the spatial distribution, but estimates from CLDAS and GLDAS are systematically higher than those from CMFD over most of mainland China. Based on our evaluation metrics, CLDAS slightly outperforms GLDAS. CLDAS is also closer than GLDAS to CMFD with respect to temporal variations in shortwave radiation anomalies, with substantial differences among the time series. Differences in temporal variations are especially pronounced south of 34° N. Our findings provide valuable guidance for a variety of stakeholders, including land-surface modelers and data providers.

scholarly journals Multi-temporal yield pattern analysis method for deriving yield zones in crop production systems

2020 ◽  
Vol 21 (6) ◽  
pp. 1263-1290
Author(s):  
Gerald Blasch ◽  
Zhenhai Li ◽  
James A. Taylor
Keyword(s):  
Crop Production ◽  
Pattern Analysis ◽  
Production Systems ◽  
Principal Component ◽  
Temporal Variations ◽  
Data Sets ◽  
Yield Data ◽  
Multi Temporal ◽  
Spatio Temporal ◽  
Cereal Fields

Abstract Easy-to-use tools using modern data analysis techniques are needed to handle spatio-temporal agri-data. This research proposes a novel pattern recognition-based method, Multi-temporal Yield Pattern Analysis (MYPA), to reveal long-term (> 10 years) spatio-temporal variations in multi-temporal yield data. The specific objectives are: i) synthesis of information within multiple yield maps into a single understandable and interpretable layer that is indicative of the variability and stability in yield over a 10 + years period, and ii) evaluation of the hypothesis that the MYPA enhances multi-temporal yield interpretation compared to commonly-used statistical approaches. The MYPA method automatically identifies potential erroneous yield maps; detects yield patterns using principal component analysis; evaluates temporal yield pattern stability using a per-pixel analysis; and generates productivity-stability units based on k-means clustering and zonal statistics. The MYPA method was applied to two commercial cereal fields in Australian dryland systems and two commercial fields in a UK cool-climate system. To evaluate the MYPA, its output was compared to results from a classic, statistical yield analysis on the same data sets. The MYPA explained more of the variance in the yield data and generated larger and more coherent yield zones that are more amenable to site-specific management. Detected yield patterns were associated with varying production conditions, such as soil properties, precipitation patterns and management decisions. The MYPA was demonstrated as a robust approach that can be encoded into an easy-to-use tool to produce information layers from a time-series of yield data to support management.

scholarly journals Long-term evolution of sunspot magnetic fields

2010 ◽  
Vol 6 (S273) ◽  
pp. 126-133 ◽  
Author(s):  
Matthew J. Penn ◽  
William Livingston
Keyword(s):  
Solar Cycle ◽  
Magnetic Fields ◽  
Spectral Line ◽  
Detailed Examination ◽  
Temporal Variations ◽  
Line Of Sight ◽  
Data Sets ◽  
Infrared Spectral ◽  
Cycle 24 ◽  
Synoptic Observations

AbstractIndependent of the normal solar cycle, a decrease in the sunspot magnetic field strength has been observed using the Zeeman-split 1564.8nm Fe I spectral line at the NSO Kitt Peak McMath-Pierce telescope. Corresponding changes in sunspot brightness and the strength of molecular absorption lines were also seen. This trend was seen to continue in observations of the first sunspots of the new solar Cycle 24, and extrapolating a linear fit to this trend would lead to only half the number of spots in Cycle 24 compared to Cycle 23, and imply virtually no sunspots in Cycle 25.We examined synoptic observations from the NSO Kitt Peak Vacuum Telescope and initially (with 4000 spots) found a change in sunspot brightness which roughly agreed with the infrared observations. A more detailed examination (with 13,000 spots) of both spot brightness and line-of-sight magnetic flux reveals that the relationship of the sunspot magnetic fields with spot brightness and size remain constant during the solar cycle. There are only small temporal variations in the spot brightness, size, and line-of-sight flux seen in this larger sample. Because of the apparent disagreement between the two data sets, we discuss how the infrared spectral line provides a uniquely direct measurement of the magnetic fields in sunspots.

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