Processing Negativity Research Articles

Prospective longitudinal investigation shows correlation of event-related potential to mild traumatic brain injury in adolescents

ABSTRACT Study Design Prospective longitudinal cohort study Background Adolescent athletes may be more susceptible to the long-term effects of mild traumatic brain injury (mTBI). A diagnostic and prognostic neuromarker may optimize management and return-to-activity decision-making in athletes who experience mTBI. Objective Measure an event-related potential (ERP) component captured with electroencephalography (EEG), called processing negativity (PN), at baseline and post-injury in adolescents who suffered mTBI and determine their longitudinal response relative to healthy controls. Methods Thirty adolescents had EEG recorded during an auditory oddball task at a pre-mTBI baseline session and subsequent post-mTBI sessions. Longitudinal EEG data from patients and healthy controls (n= 77) were obtained from up to four sessions in total and processed using Brain Network Analysis algorithms. Results The average PN amplitude in healthy controls significantly decreased over sessions 2 and 3; however, it remained steady in the mTBI group’s 2nd (post-mTBI) session and decreased only in sessions 3 and 4. Pre- to post-mTBI amplitude changes correlated with the time interval between sessions. Conclusion These results demonstrate that PN amplitude changes may be associated with mTBI exposure and subsequent recovery in adolescent athletes. Further study of PN may lead to it becoming a neuromarker for mTBI prognosis and return-to-activity decision-making in adolescents.

Auditory stimulus- and response-locked ERP components and behavior.

To clarify the functional significance of Go event-related potential (ERP) components, this study aimed to explore stimulus- and response-locked ERP averaging effects on the series of ERP components elicited during an auditory Go/NoGo task. Go stimulus- and response-locked ERP data from 126 healthy young adults (Mage =20.3, SD=2.8years, 83 female) were decomposed using temporal principal components analysis (PCA). The extracted components were then identified as stimulus-specific, response-specific, or common to both stimulus- and response-locked data. MANOVAs were then used to test for stimulus- versus response-locked averaging effects on common component amplitudes to determine their primary functional significance (i.e., stimulus- or response-related). Go stimulus- and response-related component amplitudes were then entered into stepwise linear regressions predicting the reaction time (RT), RT variability, and omission errors. Nine ERP components were extracted from the stimulus- and response-locked data, including N1-1, processing negativity (PN), P2, response-related N2 (RN2), motor potential (MP), P3b, P420, and two slow wave components; SW1 and SW2. N1-1, PN, and P2 were stimulus-specific, whereas, RN2, MP, and P420 were response-specific; P3b, SW1, and SW2 were common to both data sets. P3b, SW1, and SW2 were significantly larger in the response-locked data, indicating that they were primarily response-related. RT, RT variability, and omission errors were predicted by various stimulus- and response-related components, providing further insight into ERP markers of auditory information processing and cognitive control. Further, the results of this study indicate the utility of quantifying some common components (i.e., Go P3b, SW1, and SW2) using the response-locked ERP.

Integration of three investigations of Novelty, Intensity, and Significance in dishabituation paradigms: A study of the phasic Orienting Reflex

Data from three published studies examining autonomic and ERP measures in variants of a dishabituation paradigm were re-analysed to clarify ambiguous novelty results. The three studies manipulated 1. Novelty, 2. Novelty and Intensity, and 3. Novelty and Significance, in auditory dishabituation paradigms at very long interstimulus intervals (ISIs). The question of whether any single ERP matches SCR as the benchmark for the phasic Orienting Reflex (OR) was also addressed. Finally, we aimed to align the re-analysed measures of this and the previous analyses with processes of Preliminary Process Theory (PPT). The SCR demonstrated decrement, recovery, and dishabituation. A summary temporal PCA extracted PN (Processing Negativity), P3a, P3b, Novelty P3, and classic SW for detailed analysis. P3b and SW showed decrement but no recovery at the change trial, while Respiratory pause (RP) and Novelty P3 demonstrated decrement and recovery, but no dishabituation. Post hoc exploration of observed power versus sample size for each of these findings confirmed their robustness. No decrement for PN was also confirmed. Five autonomic and ERP groupings emerged and aligned with modules of processing in PPT: ECR1 (cardiac deceleration), P1, N1-3, and PN – stimulus registration; RP and Novelty P3 – Novelty registration; Peripheral Vasoconstriction (PVC) and P3b – Intensity registration; and ECR2 (cardiac acceleration) and classic SW – Response system. The SCR was confirmed as the sole index of the phasic OR. The pattern of results for the Late Positive Complex (LPC) components (P3a, P3b, Novelty P3, and SW) suggests each is differentially sensitivity to selective determinants of the phasic OR, and consequently the summary LPC is presented as the most appropriate central index of the phasic OR.

The influence of the global/local probability effect on the neural processing of cues and targets. A functional systems approach.

Global and local probability effects were explored in a visuo-auditory version of the central cue Posner's paradigm through the analysis of the neural Event-Related Potentials (ERPs) generated in the interaction between validity sequence effects (local probability) and block validity effects (global probability). Four behavioral measures (response times, correct/incorrect anticipations, and incorrect responses), three pre-target ERPs (visual P1/N1 and Contingent Negative Variation (CNV)), and six post-target ERPs (auditory N1, P2, Processing Negativity (PN), P3a, P3b and Late Slow Positivity (LSP)) were considered. Four types of trial-sequences (Valid-Valid, Invalid-Valid, Invalid-Invalid, Valid-Invalid) and three types of trial-blocks, with different validity/invalidity proportions (50%, 68%, and 86% of valid trials), were employed. Present data replicate previous reports on the validity sequence effects on ERPs (local probability): (i) higher CNV on trials preceded by valid trials; (ii) higher PN on valid trials preceded by invalid trials compared to valid trials preceded by valid trials; and (iii) higher P3a/P3b and LSP on invalid trials preceded by valid trials compared to invalid trials preceded by invalid trials. In summary, local probability showed more effects modulating the brain responses than global probability and/or their interaction. Among a number of other hypotheses, the functional systems theory would account for the ability of the previous trial to modify processing in the current trial.

Selective attention in children with reading disorders

Objective: This work was designed to assess the selective attention in children with reading disorder (RD) using negative difference wave test (Nd) or processing negativity (PN) and Stroop test.Design: The study included 40 children, divided into two groups; study group (SG) and control group (CG). SG consisted of 20 children with [RD]. CG consists of 20 normal children. All children were submitted to basic audiological evaluation, negative difference (Nd) wave test and Stroop test.Results: The reading disorder (RD) group showed delayed latency and decreased amplitude for both components of Nd. Results of Stroop test were significantly high among children with reading disorder compared with normal control.Conclusion: In children with learning disability, selective attention is affected. Poor selective attention may contribute to poor letter and word recognition.

Testing the Go/NoGo processing schema for children with caffeine

Event Abstract Back to Event Testing the Go/NoGo processing schema for children with caffeine Robert J. Barry1* and Frances M. De Blasio1 1 University of Wollongong, School of Psychology, Australia Aims: We recently developed a processing schema to describe the cognitive stages in the equiprobable auditory Go/NoGo task. Based on the PCA-derived ERP components observed in young adults, this has been used in a range of studies, and gradually extended to older and younger groups. A separate schema was developed for children, and recently updated using improved methodology involving separate Go and NoGo PCAs. Here we test the appropriate segregation of components in the separate Go and NoGo processing streams using caffeine’s stimulant properties; processing-specific components in each stream should be amplified by caffeine. Methods: Twenty-four children, aged 8-12 years and light-moderate caffeine users, participated in two sessions 1 week apart. A single oral dose of caffeine (80 mg) was presented in a randomised double-blind placebo-controlled repeated-measures cross-over design. Each session included 4 blocks of 150 tones; half were 1000 Hz, half were 1500 Hz, presented in random order, with the target tone balanced over subjects/sessions. EEG was recorded at 512 Hz from 19 scalp sites. Artefact-free Go and NoGo trials were separately averaged to form ERPs (-100 to + 750 ms) for the Caffeine and Placebo sessions, and each dataset was subjected to temporal PCA using covariance input, with extraction and Varimax rotation of all components. Results: Components extracted in Caffeine and Placebo matched those expected from the updated Child Processing Schema. Caffeine enhanced the Go Processing Negativity (PN), N2c, and P3b components. In NoGo, the PN and N2b components were enhanced. These caffeine amplifications match expectations of PN marking the end of stimulus categorisation, and the subsequent separate Go (N2c, P3b) and NoGo (N2b) processing streams. Conclusions: The amplifying/arousal properties of caffeine have confirmed the appropriateness of the major elements in our Processing Schema for children in this task. Keywords: Children, Caffeine, ERPs, Go NoGo task, Temporal PCA, Processing Schema Conference: ASP2017: 27th Annual Meeting for the Australasian Society for Psychophysiology, Parramatta, Australia, 29 Nov - 1 Dec, 2017. Presentation Type: Oral Presentation Topic: Abstract (General) Citation: Barry RJ and De Blasio FM (2019). Testing the Go/NoGo processing schema for children with caffeine. Conference Abstract: ASP2017: 27th Annual Meeting for the Australasian Society for Psychophysiology. doi: 10.3389/conf.fnhum.2017.224.00039 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 28 Sep 2017; Published Online: 25 Jan 2019. * Correspondence: Prof. Robert J Barry, University of Wollongong, School of Psychology, Wollongong, NSW, 2522, Australia, rbarry@uow.edu.au Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Robert J Barry Frances M De Blasio Google Robert J Barry Frances M De Blasio Google Scholar Robert J Barry Frances M De Blasio PubMed Robert J Barry Frances M De Blasio Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Sequential Processing and the Matching-Stimulus Interval Effect in ERP Components: An Exploration of the Mechanism Using Multiple Regression.

In oddball tasks, increasing the time between stimuli within a particular condition (target-to-target interval, TTI; nontarget-to-nontarget interval, NNI) systematically enhances N1, P2, and P300 event-related potential (ERP) component amplitudes. This study examined the mechanism underpinning these effects in ERP components recorded from 28 adults who completed a conventional three-tone oddball task. Bivariate correlations, partial correlations and multiple regression explored component changes due to preceding ERP component amplitudes and intervals found within the stimulus series, rather than constraining the task with experimentally constructed intervals, which has been adequately explored in prior studies. Multiple regression showed that for targets, N1 and TTI predicted N2, TTI predicted P3a and P3b, and Processing Negativity (PN), P3b, and TTI predicted reaction time. For rare nontargets, P1 predicted N1, NNI predicted N2, and N1 predicted Slow Wave (SW). Findings show that the mechanism is operating on separate stages of stimulus-processing, suggestive of either increased activation within a number of stimulus-specific pathways, or very long component generator recovery cycles. These results demonstrate the extent to which matching-stimulus intervals influence ERP component amplitudes and behavior in a three-tone oddball task, and should be taken into account when designing similar studies.

Intra-Individual Response Variability: Insights from ERP Topographies

Event Abstract Back to Event Intra-Individual Response Variability: Insights from ERP Topographies Diana Karamacoska1*, Robert J. Barry1 and Genevieve Z. Steiner1, 2 1 University of Wollongong, School of Psychology, Australia 2 Western Sydney University, NICM, Australia Aims Event-related potential (ERP) studies of intra-individual reaction time variability (IRTV) consistently report associations with the P3b, attributing highly variable outcomes to lapses in attention and decision-making processes. The extent of these effects in stimulus-response processes are, however, unknown and so the present study investigated Go ERP component differences in individuals identified as having low or high response variability in a Go/NoGo task. Method Continuous EEG data from 46 healthy participants (aged 18-27 years) were recorded during an auditory equiprobable Go/NoGo paradigm, where a button press was required for the Go but not for the NoGo tone. Mean RTs, IRTV (calculated as the within-subject standard deviation of RT), and error rates were assessed, with participants sorted and evenly divided into two groups according to Go IRTV results (n = 23 in each group). Go ERPs were epoched -100 to 700 ms around stimulus onset, and submitted to temporal PCA for component identification. The following ERP components were extracted: N1-1, Processing Negativity (PN), P2, N2c, P3b, Slow Wave (SW), and Late Negativity (LN). Component amplitudes were statistically compared between the low and high IRTV groups. Results Significant group differences were evident behaviourally as those with high IRTV produced more Go/NoGo errors than the low IRTV group. In terms of ERP component topographies, N1-1, PN, and P2 amplitudes did not differ between groups. In the following components, however, high IRTV individuals showed greater centroparietal N2c negativity and reduced midline P3b amplitude, followed by larger central SW positivity. The LN did not differ between groups. Conclusion Individuals with high IRTV exhibited poorer task performance outcomes and employed greater cognitive efforts for Go response facilitations, as reflected by the larger N2c amplitude, reduced P3b, and SW enhancement. How task- or stimulus-related preparatory activity contributes to these outcomes requires further investigation. Keywords: response variability, Cognition, Attention, decision-making, event-related potentials (ERPs), Principal Components Analysis (PCA) Conference: ASP2016 - The 26th Annual Meeting of the Australasian Society for Psychophysiology, Adelaide Australia, Adelaide,SA, Australia, 12 Dec - 14 Dec, 2016. Presentation Type: Poster Presentation Topic: Abstract (student award) Citation: Karamacoska D, Barry RJ and Steiner GZ (2016). Intra-Individual Response Variability: Insights from ERP Topographies. Conference Abstract: ASP2016 - The 26th Annual Meeting of the Australasian Society for Psychophysiology, Adelaide Australia. doi: 10.3389/conf.fnhum.2016.221.00018 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 31 Oct 2016; Published Online: 05 Dec 2016. * Correspondence: Miss. Diana Karamacoska, University of Wollongong, School of Psychology, Wollongong, Australia, d.karamacoska@westernsydney.edu.au Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Diana Karamacoska Robert J Barry Genevieve Z Steiner Google Diana Karamacoska Robert J Barry Genevieve Z Steiner Google Scholar Diana Karamacoska Robert J Barry Genevieve Z Steiner PubMed Diana Karamacoska Robert J Barry Genevieve Z Steiner Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Prestimulus low frequency EEG affects processing outcomes in the equiprobable Go/NoGo task in healthy ageing

Event Abstract Back to Event Prestimulus low frequency EEG affects processing outcomes in the equiprobable Go/NoGo task in healthy ageing Frances M. De Blasio1* and Robert J. Barry1 1 University of Wollongong, School of Psychology, Australia Prestimulus brain states have a significant impact on task-related processing outcomes, although little is known about the specific nature of these complex effects, or how consistent they are across the lifespan. Improved methodology is utilised to extend and clarify the pattern and nature of these relationships in the auditory equiprobable Go/NoGo paradigm, with a focus on the contributions in the lower frequency bands in young and well-functioning older adults. Prestimulus amplitudes in delta (0.5–3.5 Hz) and theta (4.0–7.5 Hz) were used to selectively sort and average the accepted Go and NoGo epochs, generating 10 sets of Go/NoGo ERPs and Go RT data for lower to higher prestimulus levels in each EEG band. ERP component amplitudes were quantified using Principal Components Analysis, and seven components were assessed: P1, N1-1, Processing Negativity (PN), P2/N2b, P3, Slow Wave (SW), and Late Positivity (LP). The pattern of prestimulus EEG band level effects was somewhat consistent with, and extends, prior work in this paradigm. Delta again generally modulated ERP component positivity, but theta produced fewer stimulus-specific effects. These effects differed topographically between the young and older adults in selected components for each sorting band. Prestimulus theta level inversely modulated Go RT variability across the young and older groups. The pattern of results is interpreted in the context of a recent sequential processing schema developed in this simple task, providing significant insight into the prestimulus brain state effects on processing outcomes, and how these change in healthy ageing. Keywords: EEG/ERP dynamics, Equiprobable auditory Go/NoGo, Principal Components Analysis (PCA), delta, theta, Healthy Ageing Conference: ASP2015 - 25th Annual Conference of the Australasian Society for Psychophysiology, Sydney, Australia, 2 Dec - 4 Dec, 2015. Presentation Type: Oral Presentation Topic: Psychophysiology Citation: De Blasio FM and Barry RJ (2015). Prestimulus low frequency EEG affects processing outcomes in the equiprobable Go/NoGo task in healthy ageing. Conference Abstract: ASP2015 - 25th Annual Conference of the Australasian Society for Psychophysiology. doi: 10.3389/conf.fnhum.2015.219.00030 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 22 Oct 2015; Published Online: 30 Nov 2015. * Correspondence: Ms. Frances M De Blasio, University of Wollongong, School of Psychology, Wollongong, NSW, 2522, Australia, francesd@uow.edu.au Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Frances M De Blasio Robert J Barry Google Frances M De Blasio Robert J Barry Google Scholar Frances M De Blasio Robert J Barry PubMed Frances M De Blasio Robert J Barry Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

ERPs in Young and Older Adults in the Equiprobable Auditory Go/NoGo Task

Event Abstract Back to Event ERPs in Young and Older Adults in the Equiprobable Auditory Go/NoGo Task Robert Barry1*, Frances De Blasio1 and Adele Cave1 1 University of Wollongong, School of Psychology, Australia Based on principal components analysis (PCA) decomposition of event-related potentials (ERPs) from a healthy university student sample, we recently proposed a processing schema in the equiprobable auditory Go/NoGo task. Early sensory components, such as the N1, mark the beginning of identification of the stimulus as Go vs. NoGo, leading to separate processing chains. Categorisation of the stimulus as "NoGo" is associated with a frontal N2b, fronto-central P3a, and an enhanced Late Positivity (LP); categorisation as "Go" is associated with a posterior N2c and P3b, and classic Slow Wave (SW), representing directed, response-related processing. We have verified this schema in other samples of young adults, and found a comparable processing sequence in a child sample. This study sought to compare these differential processing chains in young and well-functioning older adults. Our young sample included 22 right-handed university students (5 male/17 female) with an age range of 18.8-24.5 (M = 20.3) years. The older group consisted of 22 hand- and gender-matched independent-living adults with an age range of 59.8-74.8 (M = 68.3) years. We presented 4 stimulus blocks each containing 75 Go and 75 NoGo tone stimuli in random order. Mean Go and NoGo ERPs from each group had substantial latency differences, and hence were subjected to separate temporal PCAs with unrestricted VARIMAX rotation. In the young, six components explained 91.5 % of the variance and were identified (in temporal order) as N1-1, Processing Negativity (PN), P2/N2b, P3a, SW and a LP. In the older adults, five components explained 91.3 % of the variance and were identified (in temporal order) as N1-1, P2, P3a, P3b, and SW. Despite the differences in their identified components, each group displayed differential responsivity to Go vs. NoGo. The patterns of results lend support to our proposed processing schema in the young, and provide evidence for a similar processing schema in older adults. Keywords: Ageing, event-related potentials (ERPs), Principal Components Analysis (PCA), Auditory equiprobable Go/NoGo task, Sequential processing schema Conference: XII International Conference on Cognitive Neuroscience (ICON-XII), Brisbane, Queensland, Australia, 27 Jul - 31 Jul, 2014. Presentation Type: Poster Topic: Cognition and Executive Processes Citation: Barry R, De Blasio F and Cave A (2015). ERPs in Young and Older Adults in the Equiprobable Auditory Go/NoGo Task. Conference Abstract: XII International Conference on Cognitive Neuroscience (ICON-XII). doi: 10.3389/conf.fnhum.2015.217.00048 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 19 Feb 2015; Published Online: 24 Apr 2015. * Correspondence: Prof. Robert Barry, University of Wollongong, School of Psychology, Wollongong, Australia, rbarry@uow.edu.au Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Robert Barry Frances De Blasio Adele Cave Google Robert Barry Frances De Blasio Adele Cave Google Scholar Robert Barry Frances De Blasio Adele Cave PubMed Robert Barry Frances De Blasio Adele Cave Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Stimulus-to-matching-stimulus interval influences N1, P2, and P3b in an equiprobable Go/NoGo task

Previous research has shown that as the stimulus-to-matching-stimulus interval (including the target-to-target interval, TTI, and nontarget-to-nontarget interval, NNI) increases, the amplitude of the P300 ERP component increases systematically. Here, we extended previous P300 research and explored TTI and NNI effects on the various ERP components elicited in an auditory equiprobable Go/NoGo task. We also examined whether a similar mechanism was underpinning interval effects in early ERP components (e.g., N1). Thirty participants completed a specially-designed variable-ISI equiprobable task whilst their EEG activity was recorded. Component amplitudes were extracted using temporal PCA with unrestricted Varimax rotation. As expected, N1, P2, and P3b amplitudes increased as TTI and NNI increased, however, Processing Negativity (PN) and Slow Wave (SW) did not show the same systematic change with interval increments. To determine the origin of interval effects in sequential processing, a multiple regression analysis was conducted on each ERP component including stimulus type, interval, and all preceding components as predictors. These analyses showed that matching-stimulus interval predicted N1, P3b, and weakly predicted P2, but not PN or SW; SW was determined by P3b only. These results suggest that N1, P3b, and to some extent, P2, are affected by a similar temporal mechanism. However, the dissimilar pattern of results obtained for sequential ERP components indicates that matching-stimulus intervals are not affecting all aspects of stimulus processing. This argues against a global mechanism, such as a pathway-specific refractory effect, and suggests that stimulus processing is occurring in parallel pathways, some of which are not affected by temporal manipulations of matching-stimulus interval.

Trial effects in single-trial ERP components and autonomic responses at very long ISIs

Single-trial data from autonomic and ERP measures were used to capture the rapidly decreasing initial responses characteristic of the orienting reflex (OR) to repeated stimuli. Stimulus–response patterns were compared to determine central analogues of autonomic indices of processes leading to the OR, and the OR itself. Participants were presented with 12 indifferent tones in an auditory dishabituation paradigm. Temporal principal component analysis (PCA) decomposed EOG-corrected ERP data for 16 subjects. Response patterns of ERPs, cardiac, and respiratory responses were compared to the phasic skin conductance response (SCR). SCR decremented over trials, recovered on the change trial, and dishabituated to the representation of the standard, meeting the formal definition of habituation required of the OR. The evoked cardiac response showed no trial effects. Respiratory pause (RP) decreased linearly over trials, recovering marginally on the change trial. Nine identifiable ERP components were extracted: P1, N1-3, N1-1, processing negativity (PN), P2, P3a, P3b, a novelty-sensitive P3 component (labelled HabP3), and the slow wave (SW). P3b and SW showed decrement over trials, but with no recovery, HabP3 showed decrement and increased response on the change trial, while the P1, N1 subcomponents, P2 and P3a were insensitive to novelty. Stimulus–response patterns of the RP and HabP3 suggest sensitivity to novelty processing, while the P1, N1-3, N-1, PN, P2, P3a and cardiac deceleration appear to mark processing prior to novelty, such as stimulus transient detection (cardiac deceleration) and/or intensity processing. This study supports predictions of preliminary process theory, demonstrating fractionation of 3 autonomic and 9 ERP components to novelty, and disconfirming the unitary nature of the OR.

Variation in semantic priming across age groups: An AERP study

Objective: To study the semantic priming effect on words across the life span by means of auditory event-related potentials (AERPs). Design: Participants heard a series of three words (S1, S2, and S3). The task was to indicate whether S2 was in the same semantic category as S3. Semantic priming was quantified as the difference between AERPs to the second word when it was semantically related to the first word (S2-R) or unrelated to the first word (S2-UR). Interest was focused entirely on the processing negativity (PN) component of the AERP to S2. The purpose of S3 was to delay the task decision so that the LPC generated by the decision would not confound the measurement of the PN component to S2. Sample: Ten children (9–11 years), 11 young adults (20–30 years), and 10 seniors (60–70 years). Results: The semantic priming effect was evident in the difference between peak amplitude of the PN component of the AERP to S2R and S2UR in all three groups. Children showed a clear asymmetry favoring the left hemisphere. In young adults, the asymmetry still favored the left hemisphere, but the degree of asymmetry was less robust. In the case of seniors, the priming effect was greater over the right hemisphere. Conclusion: Results suggest that all age groups benefit from contextual support, as evidenced by the semantic priming effect. However, differences in hemispheric asymmetry of activation indicate that perhaps seniors may need to recruit additional, but somewhat different brain resources to manage otherwise largely automatic tasks.

Sequential processing in the equiprobable auditory Go/NoGo task: A temporal PCA study

The unwarned auditory equiprobable Go/NoGo task provides a convenient means to assess differential processing, although our interpretations remain limited by the lack of research regarding the range of elicited components and their functional significance. We examined sequential processing in this paradigm, presenting 24 participants with a total of 300 trials in two blocks. EEG was recorded from 19 channels, and the Go and NoGo event-related potentials were decomposed using temporal Principal Components Analysis. Of the 218 unrestricted Varimax-rotated factors, seven were identifiable as components based on their latency, polarity, and topography: early N1, Processing Negativity (PN), and P2 components were followed by N2, P3, the classic Slow Wave (SW), and a diffuse Late Positivity (LP). N1 was enhanced to Go, as was the defining temporal topography of PN. NoGo produced increased centroparietal P2, frontocentral N2, and P3a, in comparison to Go, which produced a more parietal N2 and P3b, and an enhanced SW. The LP was larger in NoGo. These results suggest that N1 marks the beginning of Go and NoGo differentiation. Complete Go/NoGo categorisation is marked by N2; this is followed by different processing chains leading to the NoGo non-response (marked by P3a) and Go response (marked by P3b and SW). The larger LP in NoGo marks the cortical inactivation following the earlier cessation of processing in this condition.

Auditory processing that leads to conscious perception: A unique window to central auditory processing opened by the mismatch negativity and related responses

In this review, we will present a model of brain events leading to conscious perception in audition. This represents an updated version of Näätänen's previous model of automatic and attentive central auditory processing. This revised model is mainly based on the mismatch negativity (MMN) and N1 indices of automatic processing, the processing negativity (PN) index of selective attention, and their magnetoencephalographic (MEG) and functional magnetic resonance imaging (fMRI) equivalents. Special attention is paid to determining the neural processes that might underlie conscious perception and the borderline between automatic and attention-dependent processes in audition.

A single high dose of escitalopram increases mismatch negativity without affecting processing negativity or P300 amplitude in healthy volunteers

Information processing deficits are commonly found in psychiatric illnesses, while at the biochemical level serotonin seems to play a role in nearly all psychiatric disorders. Processing negativity (PN), mismatch negativity (MMN) and P300 amplitude are electrophysiological measures of information processing. The present study was designed to replicate and further extent the results of our initial study on the effects of a low dose of escitalopram (10 mg) on MMN, PN and P300 amplitude. In a randomised, double-blind, cross-over experiment, 20 healthy male volunteers received either a single, orally administered dose of 15 mg escitalopram (a highly selective serotonin reuptake inhibitor (SSRI)) or placebo, after which their PN, MMN and P300 amplitude were assessed. Similar to our initial study with 10 mg escitalopram, 15 mg escitalopram significantly increased MMN, while it did not affect P300 amplitude. In contrast to our initial study, however, the currently higher dose of escitalopram did not increase PN. Results support the view that a broad range of increased serotonergic activity enhances MMN, while the relationship between serotonin and PN seems more complex. The current study does not support a serotonergic involvement in P300 amplitude.

Divergent effects of increased serotonergic activity on psychophysiological parameters of human attention

Selective serotonin reuptake inhibitors (SSRIs) are frequently combined to the antipsychotic medication of schizophrenia patients, to treat their depressed, cognitive or negative symptoms. No convincing neurochemical theory exists for this combination. The role of serotonin in those psychophysiological parameters of attention that are already found to be disturbed in schizophrenia, e.g. processing negativity (PN), mismatch negativity (MMN) and P300 amplitude, is poorly understood. In the present study the effects of increased serotonergic activity on these psychophysiological parameters is investigated. In a balanced, double-blind, placebo-controlled, cross-over experiment 18 healthy male volunteers received an oral dose of either placebo or of 10 mg escitalopram (a highly specific SSRI) on two separate test days, after which they were tested in an auditory selective attention paradigm and a MMN paradigm. Escitalopram significantly increased PN and MMN compared to placebo, without affecting the P300 amplitude. Furthermore, administration of escitalopram resulted in a small, yet significant, reduction of task performance in the selective attention paradigm compared to placebo, while it did not affect reaction time. Contrary to what was expected, escitalopram enhanced PN and MMN, without affecting the P300 amplitude. The results are discussed in the light of dosage issues and subtypes of serotonergic receptors.

No effects of l-dopa and bromocriptine on psychophysiological parameters of human selective attention

Patients with schizophrenia exhibit diverse cognitive deficits, one of which is a loss of the ability to focus attention. According to the revised dopamine hypothesis of schizophrenia both an increased mesolimbic and a decreased prefrontal dopaminergic activity is suggested to be involved in schizophrenia. The current study was designed to explore the relationship between dopamine and two psychophysiological parameters of selective attention, i.e. P300 amplitude and processing negativity (PN) in healthy volunteers. In two separate experiments, with a double-blind, balanced and placebo-controlled crossover design, 18 healthy male volunteers were orally administered either 300 mg l-dopa (precursor of dopamine) or placebo (experiment I), or 1.25mg bromocriptine (D2 agonist) or placebo (experiment II). Following this treatment they were tested in an auditory, dichotic selective attention paradigm. An increase in P300 amplitude was found following deviant stimuli when compared to standard stimuli and following attended stimuli when compared to unattended stimuli, regardless of treatment. Similarly, PN was found regardless of treatment. Neither l-dopa nor bromocriptine affected task performance or the amplitudes of PN or P300. In the present study neither l-dopa nor bromocriptine affected PN, P300 amplitude or task performance in healthy controls, phenomena which are usually found to be disrupted in schizophrenia. This indicates that P300 amplitude and PN are neither affected by a global (l-dopa) increased dopaminergic activity, nor by a more selectively towards striatal areas targeted (bromocriptine) increase in dopaminergic activity.

Impaired attentional modulation of auditory evoked potentials in N‐methyl‐d‐aspartate NR1 hypomorphic mice

In human neurophysiology, auditory event-related potentials (AEPs) are used to investigate cognitive processes such as selective attention. Selective attention to specific tones causes a negative enhancement of AEPs known as processing negativity (PN), which is reduced in patients with schizophrenia. The evidence suggests that impaired selective attention in these patients may partially depend on deficient N-methyl-D-aspartate receptor (NMDAR)-mediated signaling. The goal of this study was to corroborate the involvement of the NMDAR in selective attention using a mouse model. To this end, we first investigated the presence of PN-like activity in C57BL/6J mice by recording AEPs during a fear-conditioning paradigm. Two alternating trains of tones, differing in stimulus duration, were presented on 7 subsequent days. One group received a mild foot shock delivered within the presentation of one train (conditioning train) on days 3-5 (conditioning days), while controls were never shocked. The fear-conditioned group (n= 9) indeed showed a PN-like activity during conditioning days manifested as a significant positive enhancement in the AEPs to the stimuli in the conditioning train that was not observed in the controls. The same paradigm was then applied to mice with reduced expression of the NMDAR1 (NR1) subunit and to a wild-type control group (each group n= 6). The NR1 mutants showed an associative AEP enhancement, but its magnitude was significantly reduced as compared with the magnitude in wild-type mice. We conclude that electrophysiological manifestations of selective attention are observable yet of different polarity in mice and that they require intact NMDAR-mediated signaling. Thus, deficient NMDAR functioning may contribute to abnormal selective attention in schizophrenia.

Abnormal Selective Attention Normalizes P3 Amplitudes in PDD

This paper studied whether abnormal P3 amplitudes in PDD are a corollary of abnormalities in ERP components related to selective attention in visual and auditory tasks. Furthermore, this study sought to clarify possible age differences in such abnormalities. Children with PDD showed smaller P3 amplitudes than controls, but no abnormalities in selective attention. Adolescents with PDD showed abnormal selective attention, as reflected by larger auditory Processing Negativity (PN) and visual N2b, but no P3 abnormalities. Dipole localizations revealed that the locations of PN generators in subjects with PDD differed from controls. It was concluded that the abnormalities in selective attention in adolescents with PDD have a normalizing effect on P3, and possibly act as a compensatory process.