Large-scale Identification and Time-course Quantification of Ubiquitylation Events During Maize Seedling De-etiolation

This research examines the mechanisms that initiate rhythmic activity in the episodic central pattern generator (CPG) underlying escape swimming in the gastropod mollusk Tritonia diomedea. Activation of the network is triggered by extrinsic excitatory input but also accompanied by intrinsic neuromodulation and the recruitment of additional excitation into the circuit. To examine how these factors influence circuit activation, a detailed simulation of the unmodulated CPG network was constructed from an extensive set of physiological measurements. In this model, extrinsic input alone is insufficient to initiate rhythmic activity, confirming that additional processes are involved in circuit activation. However, incorporating known neuromodulatory and polysynaptic effects into the model still failed to enable rhythmic activity, suggesting that additional circuit features are also required. To delineate the additional activation requirements, a large-scale parameter-space analysis was conducted (∼2 × 106 configurations). The results suggest that initiation of the swim motor pattern requires substantial reconfiguration at multiple sites within the network, especially to recruit ventral swim interneuron-B (VSI) activity and increase coupling between the dorsal swim interneurons (DSIs) and cerebral neuron 2 (C2) coupling. Within the parameter space examined, we observed a tendency for rhythmic activity to be spontaneous and self-sustaining. This suggests that initiation of episodic rhythmic activity may involve temporarily restructuring a nonrhythmic network into a persistent oscillator. In particular, the time course of neuromodulatory effects may control both activation and termination of rhythmic bursting.

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Large-scale Dynamics of Perceptual Decision Information across Human Cortex

10.1101/2020.02.01.929893 ◽

2020 ◽

Cited By ~ 1

Author(s):

Niklas Wilming ◽

Peter R Murphy ◽

Florent Meyniel ◽

Tobias H Donner

Keyword(s):

Large Scale ◽

Time Course ◽

Action Plan ◽

Frequency Channel ◽

Human Cortex ◽

Cortical Hierarchy ◽

Specific Frequency ◽

Sensory Evidence ◽

Visual Cortical ◽

Endogenous Component

AbstractPerceptual decisions entail the accumulation of sensory evidence for a particular choice towards an action plan. An influential framework holds that sensory cortical areas encode the instantaneous sensory evidence and downstream, action-related regions accumulate this evidence. The large-scale distribution of this computation across the cerebral cortex has remained largely elusive. We developed a regionally-specific magnetoencephalography decoding approach to exhaustively map the dynamics of stimulus- and choice-specific signals across the human cortical surface during a visual decision. Comparison with the evidence accumulation dynamics inferred from behavior enabled us to disentangle stimulus-dependent and endogenous components of choice-predictive activity across the visual cortical hierarchy. The endogenous component was present in primary visual cortex, expressed in a low (< 20 Hz) frequency-band, and its time course tracked, with delay, the build-up of choice-predictive activity in (pre-)motor regions. Our results are consistent with choice-specific cortical feedback signaling in a specific frequency channel during decision formation.

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Short-term emersion affects cardiac function and regional haemolymph distribution in the crab Cancer magister

Journal of Experimental Biology ◽

10.1242/jeb.199.3.569 ◽

1996 ◽

Vol 199 (3) ◽

pp. 569-578

Author(s):

C Airriess ◽

B Mcmahon

Keyword(s):

Stroke Volume ◽

Cardiac Function ◽

Large Scale ◽

Time Course ◽

Beat Frequency ◽

Heart Beat ◽

Experimental Chamber ◽

Cancer Magister ◽

Flow Through ◽

Cardiac Stroke Volume

Changes in cardiac function and arterial haemolymph flow associated with 6 h of emersion were investigated in the crab Cancer magister using an ultrasonic flowmeter. This species is usually found sublittorally but, owing to the large-scale horizontal water movements associated with extreme tides, C. magister may occasionally become stranded on the beach. Laboratory experiments were designed such that the emersion period was typical of those that might be experienced by this crab in its natural environment. The frequency of the heart beat began to decline sharply almost immediately after the start of the experimental emersion period. Cardiac stroke volume fell more gradually. The combined reduction in these two variables led to a maximum decrease in cardiac output of more than 70 % from the control rate. Haemolymph flow through all the arteries originating at the heart, with the exception of the anterior aorta, also declined markedly during emersion. As the water level in the experimental chamber fell below the inhalant branchial openings, a stereotypical, dramatic increase in haemolymph flow through the anterior aorta began and this continued for the duration of the emersion period. The rapid time course of the decline in heart-beat frequency and the increase in haemolymph flow through the anterior aorta suggest a neural mechanism responding to the absence of ventilatory water in the branchial chambers. These responses may be adaptations, respectively, to conserve energy by reducing the minute volume of haemolymph pumped by the heart and to protect the supply of haemolymph to cephalic elements of the central nervous system. The decline in cardiac stroke volume, which occurs more slowly over the emersion period, may be a passive result of the failure to supply sufficient O2 to meet the aerobic demands of the cardiac ganglion.

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Large-Scale Desynchronization During Interictal Epileptic Discharges Recorded With Intracranial EEG

Frontiers in Neurology ◽

10.3389/fneur.2020.529460 ◽

2020 ◽

Vol 11 ◽

Author(s):

Elie Bou Assi ◽

Younes Zerouali ◽

Manon Robert ◽

Frederic Lesage ◽

Philippe Pouliot ◽

...

Keyword(s):

Functional Connectivity ◽

Large Scale ◽

Time Course ◽

Deep Understanding ◽

Epileptic Focus ◽

Epileptogenic Focus ◽

Intracranial Eeg ◽

Epileptiform Discharges ◽

Potential Biomarker ◽

Epileptic Discharges

It is increasingly recognized that deep understanding of epileptic seizures requires both localizing and characterizing the functional network of the region where they are initiated, i. e., the epileptic focus. Previous investigations of the epileptogenic focus' functional connectivity have yielded contrasting results, reporting both pathological increases and decreases during resting periods and seizures. In this study, we shifted paradigm to investigate the time course of connectivity in relation to interictal epileptiform discharges. We recruited 35 epileptic patients undergoing intracranial EEG (iEEG) investigation as part of their presurgical evaluation. For each patient, 50 interictal epileptic discharges (IEDs) were marked and iEEG signals were epoched around those markers. Signals were narrow-band filtered and time resolved phase-locking values were computed to track the dynamics of functional connectivity during IEDs. Results show that IEDs are associated with a transient decrease in global functional connectivity, time-locked to the peak of the discharge and specific to the high range of the gamma frequency band. Disruption of the long-range connectivity between the epileptic focus and other brain areas might be an important process for the generation of epileptic activity. Transient desynchronization could be a potential biomarker of the epileptogenic focus since 1) the functional connectivity involving the focus decreases significantly more than the connectivity outside the focus and 2) patients with good surgical outcome appear to have a significantly more disconnected focus than patients with bad outcomes.

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Reduced Brain Electric Activity and Functional Connectivity in Bipolar Euthymia: An sLORETA Source Localization Study

Clinical EEG and Neuroscience ◽

10.1177/1550059419893472 ◽

2019 ◽

Vol 51 (3) ◽

pp. 155-166

Author(s):

Annamaria Painold ◽

Pascal L. Faber ◽

Eva Z. Reininghaus ◽

Sabrina Mörkl ◽

Anna K. Holl ◽

...

Keyword(s):

Functional Connectivity ◽

Large Scale ◽

Time Course ◽

Temporal Cortex ◽

Electric Activity ◽

Brain Regions ◽

Frequency Bands ◽

Head Surface ◽

Density Values ◽

Surface Eeg

Bipolar disorder (BD) is a chronic illness with a relapsing and remitting time course. Relapses are manic or depressive in nature and intermitted by euthymic states. During euthymic states, patients lack the criteria for a manic or depressive diagnosis, but still suffer from impaired cognitive functioning as indicated by difficulties in executive and language-related processing. The present study investigated whether these deficits are reflected by altered intracortical activity in or functional connectivity between brain regions involved in these processes such as the prefrontal and the temporal cortices. Vigilance-controlled resting state EEG of 13 euthymic BD patients and 13 healthy age- and sex-matched controls was analyzed. Head-surface EEG was recomputed into intracortical current density values in 8 frequency bands using standardized low-resolution electromagnetic tomography. Intracortical current densities were averaged in 19 evenly distributed regions of interest (ROIs). Lagged coherences were computed between each pair of ROIs. Source activity and coherence measures between patients and controls were compared (paired t tests). Reductions in temporal cortex activity and in large-scale functional connectivity in patients compared to controls were observed. Activity reductions affected all 8 EEG frequency bands. Functional connectivity reductions affected the delta, theta, alpha-2, beta-2, and gamma band and involved but were not limited to prefrontal and temporal ROIs. The findings show reduced activation of the temporal cortex and reduced coordination between many brain regions in BD euthymia. These activation and connectivity changes may disturb the continuous frontotemporal information flow required for executive and language-related processing, which is impaired in euthymic BD patients.

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National survey of viruses in pastures of subterranean clover. II. Statistical methodology for large scale quantitative ELISA

Australian Journal of Agricultural Research ◽

10.1071/ar9931863 ◽

1993 ◽

Vol 44 (8) ◽

pp. 1863

Author(s):

WJ Muller ◽

K Helms ◽

PM Waterhouse

Keyword(s):

Large Scale ◽

Time Course ◽

Alfalfa Mosaic Virus ◽

Subterranean Clover ◽

Plant Sample ◽

Statistical Methodology ◽

Plate Design ◽

Field Samples ◽

Healthy Control ◽

Sole Criterion

Statistical methodology was applied to a survey of time-course incidence of four viruses (alfalfa mosaic virus, clover yellow vein virus, subterranean clover mottle virus and subterranean clover red leaf virus) in improved pastures in southern regions of Australia, with samplings in each winter and spring over 3 years. The 100 samples per paddock collected at each time of sampling provided detection probabilities of 0.63 and 0.87 for 1% and 2% infection respectively. A microtitre plate design for ELISA was developed to include 60 field samples, 10 glasshouse-grown healthy control samples and 6 glasshouse-grown samples infected with the virus under examination. This design was used on 816 plates for each of the four viruses tested. The method used for identification of virus in sap of a plant sample from a particular paddock was that the ELISA reading was both significantly greater than healthy control readings, and an outlier in the distribution of readings of all sap samples from that paddock. It is argued that as the identification of uninfected samples as infected was highly unlikely, this double criterion method was superior to the use of each criterion separately. Use of significance above healthy control values as the sole criterion would have increased virus incidences by about 60%; use of outlier identification as the sole criterion would have increased virus incidences by about 30%. A generalized linear model with binomial errors and logit link was used for adjusting the virus incidences reported in the previous paper (Helms et al. 1993) for biases due to paddocks and/or districts not sampled on some occasions. This adjustment slightly increased overall incidences in all but one sampling and confirmed the time-course increase in incidence over the 3 years of the survey. The same model also proved to be the most appropriate for investigating the effects of year, season and district on virus incidence.

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Venous thromboembolism in patients with renal cell carcinoma: Incidence, risk factors, and prognostic implication.

Journal of Clinical Oncology ◽

10.1200/jco.2012.30.5_suppl.446 ◽

2012 ◽

Vol 30 (5_suppl) ◽

pp. 446-446 ◽

Cited By ~ 1

Author(s):

Ha-young Lee ◽

Eunhee Park ◽

Soohyeon Lee ◽

Soojung Hong ◽

Hyun Jung Park ◽

...

Keyword(s):

Risk Factors ◽

Venous Thromboembolism ◽

Cumulative Incidence ◽

Renal Cell ◽

Large Scale ◽

Time Course ◽

Stage Iv ◽

Severance Hospital ◽

Incidence Risk ◽

Ecog Ps

446 Background: Renal cell ca (RCC) is one of solid tumor with relatively highest incidence of venous thromboembolism (VTE). But, there have been to no large-scale studies that focused on VTE in RCC. The aim of this study was to investigate the incidence, time course of VTE, risk factors, and prognosis associated with VTE in RCC patients in Korea. Methods: The medical records of RCC patients (n=1248) histologically diagnosed at Severance Hospital, Yonsei University College of Medicine, Seoul, Korea from Jan 2005 to Mar 2011 were retrospectively reviewed. Results: Among 1248 RCC patients, 69.6% were men, median age was 56years (range: 4∼89), and stage distribution was stage I 65.1%, stage II 9.2%, stage III 10.4%, stage IV 12.5%. The 2-year cumulative incidences of tumor induced VTE (tVTE) was detected in 78 patients (6.3%), while 1-month, 6-months and 1-year cumulative incidence of tVTE were 5.3%, 5.7% and 6.0%, retrospectively. Two-year cumulative incidence of tVTE seemed to increase with stage (0.6%, 3.5%, 22.3% and 24.3% in stages I, II, III and IV, retrospectively). Almost tVTE events developed in the first few months after diagnosis. Stage and metastatic disease were independent risk factors for developing tVTE. In multivariate analysis, the development of tVTE was a significant predictor of survival (P=0.004) and stage, age, ECOG PS was also independent predictor of survival. Conclusions: This is the first study that specially focused on tVTE in RCC. The 2-year cumulative incidence of tVTE in Korean patients with RCC was 6.3%, which is similar to other ethnic group. As tVTE related to poorer survival, RCC patients with advanced stage and metastasis with higher risk of tVTE, close follow-up is recommended and proactive prophylaxis of VTE might be needed.

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An Approach to Inferring Transcriptional Regulation Among Genes From Large-Scale Expression Data

Comparative and Functional Genomics ◽

10.1002/cfg.237 ◽

2003 ◽

Vol 4 (1) ◽

pp. 148-154 ◽

Cited By ~ 8

Author(s):

Javier Herrero ◽

Ramón Díaz-Uriarte ◽

Joaquín Dopazo

Keyword(s):

Large Scale ◽

Time Course ◽

Dna Microarrays ◽

Genetic Network ◽

Genetic Networks ◽

Gene Interactions ◽

Expression Data ◽

Dynamic Correlations ◽

Common Time ◽

Data Points

The use of DNA microarrays opens up the possibility of measuring the expression levels of thousands of genes simultaneously under different conditions. Time-course experiments allow researchers to study the dynamics of gene interactions. The inference of genetic networks from such measures can give important insights for the understanding of a variety of biological problems. Most of the existing methods for genetic network reconstruction require many experimental data points, or can only be applied to the reconstruction of small subnetworks. Here we present a method that reduces the dimensionality of the dataset and then extracts the significant dynamic correlations among genes. The method requires a number of points achievable in common time-course experiments.

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Neuronal Synchronization and Selective Color Processing in the Human Brain

Journal of Cognitive Neuroscience ◽

10.1162/089892904322926827 ◽

2004 ◽

Vol 16 (3) ◽

pp. 503-522 ◽

Cited By ~ 62

Author(s):

Matthias M. Müller ◽

Andreas Keil

Keyword(s):

Large Scale ◽

Time Course ◽

Time Window ◽

Brain Activity ◽

Stimulus Onset ◽

Gamma Band ◽

Event Related Potential ◽

Alpha Band ◽

Color Processing ◽

The Time Domain

In the present study, subjects selectively attended to the color of checkerboards in a feature-based attention paradigm. Induced gamma band responses (GBRs), the induced alpha band, and the event-related potential (ERP) were analyzed to uncover neuronal dynamics during selective feature processing. Replicating previous ERP findings, the selection negativity (SN) with a latency of about 160 msec was extracted. Furthermore, and similarly to previous EEG studies, a gamma band peak in a time window between 290 and 380 msec was found. This peak had its major energy in the 55to 70-Hz range and was significantly larger for the attended color. Contrary to previous human induced gamma band studies, a much earlier 40to 50-Hz peak in a time window between 160 and 220 msec after stimulus onset and, thus, concurrently to the SN was prominent with significantly more energy for attended as opposed to unattended color. The induced alpha band (9.8–11.7 Hz), on the other hand, exhibited a marked suppression for attended color in a time window between 450 and 600 msec after stimulus onset. A comparison of the time course of the 40to 50-Hz and 55to 70-Hz induced GBR, the induced alpha band, and the ERP revealed temporal coincidences for changes in the morphology of these brain responses. Despite these similarities in the time domain, the cortical source configuration was found to discriminate between induced GBRs and the SN. Our results suggest that large-scale synchronous high-frequency brain activity as measured in the human GBR play a specific role in attentive processing of stimulus features.

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