EEG Signal Decomposition Evidence for a Role of Perceptual Processes during Conflict-related Behavioral Adjustments in Middle Frontal Regions

2020 ◽  
Vol 32 (7) ◽  
pp. 1381-1393
Author(s):  
Nico Adelhöfer ◽  
Christian Beste
Keyword(s):  
Time Window ◽  
Flanker Task ◽  
Decomposition Methods ◽  
Signal Decomposition ◽  
Conflict Monitoring ◽  
Stimulus Response ◽  
Eeg Data ◽  
Congruency Sequence Effect ◽  
Trial History

Conflict monitoring processes are central to cope with fluctuating environmental demands. However, the efficacy of these processes depends on previous trial history/experience, which is reflected in the “congruency sequence effect” (CSE). Several theoretical accounts have been put forward to explain this effect. Some accounts stress the role of perceptual processes in the emergence of the CSE. As yet, it is elusive how these perceptual processes are implemented on a neural level. We examined this question using a newly developed moving dots flanker task. We combine decomposition methods of EEG data and source localization. We show that perceptual processes modulate the CSE and can be isolated in neurophysiological signals, especially in the N2 ERP time window. However, mechanisms relating perception to action are also coded and modulated in this time window. We show that middle frontal regions (BA 6) are associated with processes dealing with purely perceptual processes. Inferior frontal regions (BA 45) are associated with processes dealing with stimulus–response transition processes. Likely, the neurophysiological modulations reflect unbinding processes at the perceptual level, and stimulus–response translation level needed to respond correctly on the presented (changed) stimulus–response relationships. The data establish a direct relationship between psychological concepts focusing on perceptual processes during conflict monitoring and neurophysiological processes using signal decomposition.

Intact Context-Dependent Modulation of Conflict Monitoring in Childhood ADHD

2016 ◽  
Vol 24 (11) ◽  
pp. 1503-1510 ◽  
Author(s):  
Annet Bluschke ◽  
Witold X. Chmielewski ◽  
Veit Roessner ◽  
Christian Beste
Keyword(s):  
Executive Control ◽  
Flanker Task ◽  
Contextual Information ◽  
Reaction Times ◽  
Healthy Controls ◽  
Conflict Monitoring ◽  
Performance Deficits ◽  
Children With Adhd ◽  
Stimulus Response ◽  
Control Functions

Objective: Conflict monitoring is well known to be modulated by context. This is known as the Gratton effect, meaning that the degree of interference is smaller when a stimulus–response conflict had been encountered previously. It is unclear to what extent these processes are changed in ADHD. Method: Children with ADHD (combined subtype) and healthy controls performed a modified version of the sequence flanker task. Results: Patients with ADHD made significantly more errors than healthy controls, indicating general performance deficits. However, there were no differences regarding reaction times, indicating an intact Gratton effect in ADHD. These results were supported by Bayesian statistics. Conclusion: The results suggest that the ability to take contextual information into account during conflict monitoring is preserved in patients with ADHD despite this disorder being associated with changes in executive control functions overall. These findings are discussed in light of different theoretical accounts on contextual modulations of conflict monitoring.

scholarly journals Intact Stimulus–Response Conflict Processing in ADHD—Multilevel Evidence and Theoretical Implications

2020 ◽  
Vol 9 (1) ◽  
pp. 234 ◽  
Author(s):  
Annet Bluschke ◽  
Moritz Mückschel ◽  
Veit Roessner ◽  
Christian Beste
Keyword(s):  
Event Related Potentials ◽  
Decomposition Methods ◽  
Individual Variability ◽  
Control Group ◽  
Adhd Group ◽  
Conflict Monitoring ◽  
Conflict Processing ◽  
Stimulus Response ◽  
Related Potentials ◽  
Multi Level

Attention-deficit-hyperactivity disorder (ADHD) is closely associated with deficits in cognitive control. It seems, however, that the degree of deficits strongly depends on the examined subprocess, with the resolution of stimulus–stimulus conflicts being particularly difficult for patients with ADHD. The picture is far less clear regarding stimulus–response conflicts. The current study provides multi-level behavioural and neurophysiological data on this type of conflict monitoring in children with ADHD compared to healthy controls. To account for the potentially strong effects of intra-individual variability, electroencephalogram (EEG) signal decomposition methods were used to analyze the data. Crucially, none of the analyses (behavioural, event-related potentials, or decomposed EEG data) show any differences between the ADHD group and the control group. Bayes statistical analysis confirmed the high likelihood of the null hypothesis being true in all cases. Thus, the data provide multi-level evidence showing that conflict monitoring processes are indeed partly intact in ADHD, even when eliminating possible biasing factors such as intra-individual variability. While stimulus–stimulus conflict processing has been shown to be consistently dysfunctional in ADHD, the resolution of stimulus–response conflicts is not deficient in this patient group. In comparison to other studies, the results provide novel theoretical insights into the nature of conflict control deficits in childhood ADHD.

scholarly journals Multiple expectancies underlie the congruency sequence effect in confound-minimized tasks

2019 ◽  
Author(s):  
Christopher Erb ◽  
Andy J. Aschenbrenner
Keyword(s):  
Flanker Task ◽  
Congruent Trial ◽  
Feature Integration ◽  
Contingency Learning ◽  
Sequence Effect ◽  
Conflict Monitoring ◽  
Recent Trial ◽  
Probe Task ◽  
Congruency Sequence Effect ◽  
Stroop Tasks

The congruency sequence effect (CSE) occurs when the congruency effect observed in tasks such as the Eriksen flanker task is smaller on trials preceded by an incongruent trial relative to trials preceded by a congruent trial. The CSE has been attributed to a range of factors including repetition expectancy, conflict monitoring, feature integration, and contingency learning. To clarify the debate surrounding the CSE and the mechanisms underlying its occurrence, researchers have developed confound-minimized congruency tasks designed to control for feature-integration and contingency-learning effects. A CSE is often observed in confound-minimized tasks, indicating that the effect is driven by repetition expectancy, conflict monitoring, or a combination of the two. Here, we propose and test a variant of the repetition expectancy account that emphasizes how multiple expectations can be formed simultaneously based upon the congruency type (congruent vs. incongruent) and the congruency repetition type (congruency repetition vs. congruency alternation) of the most recent trial. Data from confound-minimized versions of the prime-probe task were found to support this novel account. Data from confound-minimized versions of the Eriksen flanker, Simon, and Stroop tasks indicate that repetition-priming confounds often remain in these tasks, potentially undermining the conclusions of previous work. We discuss the implications of these findings for ongoing theoretical debates surrounding the CSE.

scholarly journals Stimulus-response coupling in the human neutrophil. The role of anion fluxes in degranulation.

1982 ◽  
Vol 257 (12) ◽  
pp. 6916-6922
Author(s):  
H M Korchak ◽  
B A Eisenstat ◽  
J E Smolen ◽  
L E Rutherford ◽  
P B Dunham ◽  
...  
Keyword(s):  
Human Neutrophil ◽  
Stimulus Response

scholarly journals Natural Zeitgebers Under Temperate Conditions Cannot Compensate for the Loss of a Functional Circadian Clock in Timing of a Vital Behavior in Drosophila

2021 ◽  
pp. 074873042199811
Author(s):  
Franziska Ruf ◽  
Oliver Mitesser ◽  
Simon Tii Mungwa ◽  
Melanie Horn ◽  
Dirk Rieger ◽  
...  
Keyword(s):  
Molecular Clock ◽  
Time Window ◽  
Fruit Fly ◽  
Diel Activity ◽  
Wild Type ◽  
Statistical Measures ◽  
Clock Mutant ◽  
Full Complement ◽  
The Right

The adaptive significance of adjusting behavioral activities to the right time of the day seems obvious. Laboratory studies implicated an important role of circadian clocks in behavioral timing and rhythmicity. Yet, recent studies on clock-mutant animals questioned this importance under more naturalistic settings, as various clock mutants showed nearly normal diel activity rhythms under seminatural zeitgeber conditions. We here report evidence that proper timing of eclosion, a vital behavior of the fruit fly Drosophila melanogaster, requires a functional molecular clock under quasi-natural conditions. In contrast to wild-type flies, period01 mutants with a defective molecular clock showed impaired rhythmicity and gating in a temperate environment even in the presence of a full complement of abiotic zeitgebers. Although period01 mutants still eclosed during a certain time window during the day, this time window was much broader and loosely defined, and rhythmicity was lower or lost as classified by various statistical measures. Moreover, peak eclosion time became more susceptible to variable day-to-day changes of light. In contrast, flies with impaired peptidergic interclock signaling ( Pdf01 and han5304 PDF receptor mutants) eclosed mostly rhythmically with normal gate sizes, similar to wild-type controls. Our results suggest that the presence of natural zeitgebers is not sufficient, and a functional molecular clock is required to induce stable temporal eclosion patterns in flies under temperate conditions with considerable day-to-day variation in light intensity and temperature. Temperate zeitgebers are, however, sufficient to functionally rescue a loss of PDF-mediated clock-internal and -output signaling

THE ROLE OF IONISED INTRACELLULAR FREE CALCIUM ([Ca++]i) IN THROMBIN-INDUCED DENSE GRANULE SECRETION

1987 ◽  
Author(s):  
C T Poll ◽  
J Westwick
Keyword(s):  
Human Platelets ◽  
Dense Granule ◽  
Free Calcium ◽  
Fluorescent Properties ◽  
Fura 2 ◽  
Stimulus Response ◽  
Dense Granules ◽  
Dense Granule Secretion ◽  
Granule Secretion

Fura 2 is one of a recently-introduced family of Ca++ indicators with improved fluorescent properties compared to quin 2 (Grynkiewicz et al 1985). This study has examined the role of [Ca++]i in thrombin-induced dense granule release using prostacyclin-washed human platelets loaded with either thedense granule marker 14C-5HT (5HT) alone or with 5HT together with quin 2 ([quin2]i = 0.8mM) or fura 2 ([fura 2]i 20-30µM). In the presence of ImM extracellular calcium concentration ([Ca++]i) the [Ca++]e in quin 2 and fura 2 loaded platelets was 93±2 (n=10 experiments) and 133±0.3nM (n=12 experiments) respectively. In either quin 2 or fura 2 loaded platelets suspended in the presence of ImM [Ca++]e, thrombin (0.23-23.InM) promoted a rapid (in secs)concentration-dependent elevation of [Ca++]i from basal values to levels l-2µM, together with a parallel release of dense granules almost identical to that obtained with thrombin in non dye loaded platelets. In fura 2 loaded cells, removal of [Ca++]e inhibited the elevation of [Ca++]i induced by a sub-maximal concentration of thrombin (0.77nM) by 43+5% (n=4) but interestingly had no significant effect (p<0.05) on the rise in [Ca++]i elicited by low thrombin doses (0.231nM). Neither did lowering [Ca++]e inhibit the release of 5HT evoked by thrombin ( 0.231-23.InM) from either fura 2 loaded or non dye loaded platelets. In contrast, in quin 2 loaded platelets, removal of [Ca++]e inhibited the thrombin (0.231-23.InM) stimulated rise in [Ca++]i-by 90% and the 5HT release response to either low (0.231nM), sub-maximal (0.77nM) or maximal (23.InM) thrombin by 100% (n=4), 87+2°/o (n=6)and 2+l°/o (n=4) respectively. Fura 2 but not quin 2 loaded cells suspended in ImM [Ca++]e exhibited a Ca++ response to thrombin concentrations >2.31nM which could be separated into a rapid phasic component and a more sustained 'tonic' like component inhibitable by removal of [Ca++]e or by addition of ImM Ni++ . These data suggest the use of fura 2 rather than quin 2 for investigating stimulus response coupling in platelets, particularly when [Ca++]e is less than physiological. We thank the British Heart Foundation and Ciba-Geigy USA for financial support.

Abstract 94: Patient Selection using CT Perfusion (CTP) Imaging Improves Effectiveness of Stroke Thrombolysis in the 0-4.5 Hour Time Window

Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Dulka Manawadu ◽  
Shankranand Bodla ◽  
Laszlo Sztriha ◽  
Josef Jarosz ◽  
Lalit Kalra
Keyword(s):  
Patient Selection ◽  
Functional Outcomes ◽  
Time Window ◽  
Ct Perfusion ◽  
Treatment Protocol ◽  
Early Improvement ◽  
Nihss Score ◽  
Ct Perfusion Imaging ◽  
Mean Blood Glucose

Background: The role of CT perfusion (CTP) in thrombolysis decisions remains controversial and there are no studies that compare outcomes of thrombolysis in patients with or without mismatch on CT perfusion imaging. Methods: We analysed registry data between Jan 2009 and December 2010 for patients thrombolysed within 0-4.5 hours of stroke onset in whom CTP studies were performed prior to thrombolysis. The centre followed thrombolysis guidelines but patients >80 years were included. CTP was not obligatory in the treatment protocol and failure to demonstrate a mismatch was not a contraindication to thrombolysis. We retrospectively analysed data for estimated CTP mismatch of ≥ 100% according to pre-defined criteria and compared outcomes of thrombolysed patients showing perfusion mismatch with those showing no mismatch. Findings: The sample included 160 patients aged between 32-95 years of whom 63 had no mismatch and 97 had a significant mismatch. The two groups were comparable for mean age (73 v 70 years, p=0.18), sex (49% v 54% male, p=0.75), premorbid Rankin Score (mRS) 0-2 (81% v 92%, p=0.77), vascular risk factors profile, mean baseline BP (148/87 v 148/79 mm Hg, p=0.92), mean blood glucose (6.6 v 6.6 mmols/L, p=0.98) and mean National Institute of Health Stroke Scale (NIHSS) score (14.0 v 12.6,p=0.12). Patients who had mismatch prior to thrombolysis showed lower mean 24 hour NIHSS score (7.6 v 11.8, p=0.002) and greater mean 24 hour improvement in NIHSS score (5.1 v 2.0, p=0.010). A higher proportion of patients with mismatch achieved mRS 0-1 and mRS 0-2 at 3 months (36% v 18%, p= 0.012 and 51% v 32%, p=0.015 respectively) but there were no differences in symptomatic sICH rates (1.1% v 0%). Mortality (29% v 18%) and any intracranial haemorrhages (19% v 13%) were lower in mismatch patients but did not achieve significance. Regression analyses showed that PCT mismatch prior to thrombolysis was an independent predictor of both early improvement and functional outcomes at 3 months. Conclusion: Stroke patients who have perfusion mismatch on CTP imaging prior to thrombolysis within the 4.5 hour time window show better early and 3 month outcomes compared with those in whom mismatch cannot be demonstrated. Patient selection using multimodal CT may improve the effectiveness of thrombolysis.

Second language (L2) proficiency, socioeconomic status (SES), and intelligence (IQ) are significant predictors of cognitive control differences among young adult unbalanced Chinese–English bilinguals

2018 ◽  
Vol 22 (04) ◽  
pp. 866-882 ◽  
Author(s):  
ZHILONG XIE ◽  
TERESA SIGNORELLI PISANO
Keyword(s):  
Socioeconomic Status ◽  
Second Language ◽  
Young Adult ◽  
Cognitive Control ◽  
Flanker Task ◽  
Incongruent Condition ◽  
Wisconsin Card Sorting Test ◽  
Card Sorting ◽  
Conflict Monitoring ◽  
L2 Proficiency

The current study investigates how second-language (L2) proficiency contributes to cognitive control differences among three groups of unbalanced Chinese–English bilinguals matched for socioeconomic status (SES), intelligence (IQ), education, age, culture, and L1 background. A Flanker task and the Wisconsin Card Sorting Test (WCST) were administered to measure conflict monitoring, inhibition, and mental set shifting. ANOVA analyses revealed faster performance for the High-L2 Group compared to the Low-L2 Group in the congruent, neutral, and incongruent conditions of the Flanker task. However, there were no group differences on the WCST. Multiple step-wise regression analyses showed that L2 proficiency was a predictor for the Flanker task performance in all three conditions, SES in the neutral and the incongruent condition, and IQ in the congruent condition. These results suggest that L2 proficiency, along with SES and IQ, contribute significantly to cognitive control differences in conflict monitoring among young-adult bilinguals.

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