ERP components and behavior in the auditory equiprobable go/no‐go task: Inhibition in young adults

Previous research suggests that young adults do not need active and effortful inhibition to successfully complete the auditory equiprobable go/no‐go task, a view that was incorporated into Barry and De Blasio's sequential processing schema for this task. However, recent evidence in children suggests that view could be incorrect. The present research aims to clarify the functionality of the N2 and P3 subcomponents within the proposed schema, assessing the role of inhibition in this task. To optimize the quantification of the N2 and P3 subcomponents, separate temporal PCAs were applied to the go/no‐go ERP data from 40 young adults. Correlations were then used to link subcomponent amplitudes with performance outcomes, informing a functional interpretation of each subcomponent. Larger N2b and P3a amplitudes were each linked to fewer commission errors. N2c amplitude also increased with intraindividual reaction time variability, but no performance outcomes were associated with P3b. These findings link the young adult N2b and P3a with inhibition in the auditory equiprobable task, confirming the importance of control for successful nontarget processing in that paradigm. The functionality of N2c and P3b remain unclear from our results. However, these outcomes improve our understanding of cognitive processing in equiprobable tasks, and contribute to an improved conceptualization of the sequential processing schema.     

Modulation of ERP components by task instructions in a cued go/no‐go task

The present study investigated how components of ERPs are modulated when participants optimize speed versus accuracy in a cued go/no‐go task. Using a crossover design, 35 participants received instructions to complete the task prioritizing response speed in half of the task, and accurate responding in the other half of the task. Analysis was performed on the contingent negative variation (CNV), P3go, and P3no‐go and the corresponding independent components (IC), as identified by group independent component analysis. After speed instructions, the IC CNV_late, P3go_anterior, P3no‐go_early, and P3no‐go_late all had larger amplitudes than after accuracy instructions. Furthermore, both the IC P3go_posterior and IC P3go_anterior had shorter latencies after speed than after accuracy instructions. The results demonstrate that components derived from the CNV and P3 components are facilitated when participants optimize response speed. These findings indicate that these ERP components reflect executive processes enabling adjustment of behavior to changing demands.     

Functional indexes of reactive cognitive control: ERPs in cued go/no‐go tasks

We aimed to determine the functional meaning of latent (hidden) components decomposed from ERPs, in the context of a go/no‐go paradigm. To accomplish this, we used a new group blind source separation method, based on joint diagonalization of covariance matrices of ERPs. Four variants of a frequently used go/no‐go paradigm were designed, in which operations of reactive cognitive control, such as conflict detection and action inhibition, were independently manipulated. The results showed that a latent component, generated in the anterior cingulate cortex, induced N2/P3 fluctuation only in conditions in which the prepotent model was violated, and thus can be associated with conflict detection operations. In contrast, the two latent components generated in the vicinity of the central sulcus induced P3‐like fluctuations in conditions in which the prepared action was suppressed, and thus can be associated with action inhibition operations. The advantages and limitations of the new blind source separation method in relation to ERP research are also discussed.     

Caffeine affects children’s ERPs and performance in an equiprobable go/no‐go task: Testing a processing schema

Caffeine’s stimulant properties were used to test a proposed processing schema for children’s processing stages in the equiprobable auditory go/no‐go task. Active control‐related ERP components were hypothesized to be differentially enhanced by caffeine. Caffeine (80 mg) was administered in a counterbalanced, randomized, double‐blind, placebo‐controlled, cross‐over study of 24 children, aged 8–12 years. Four blocks of an equiprobable auditory go/no‐go task were completed on each of two occasions, while on or off caffeine. ERP data sets from each condition (caffeine/go, placebo/go, caffeine/no‐go, placebo/no‐go) were subjected to separate temporal PCAs with extraction and varimax rotation of all components. Caffeine significantly reduced reaction time and go omission errors, and enhanced go PN, N2c, and P3b, and no‐go N1‐1 and N2b. This selective enhancement of different go/no‐go components by caffeine matched the predicted amplification of biomarkers of children’s active control processing in this task. Some unexpected findings also support further refinements in the child processing schema.     

Effects of a startle stimulus on response speed and inhibition in a go/no‐go task

Two studies examined the interaction of an acoustic startle stimulus and visual go/no‐go task stimuli on startle reactivity and task performance. In the first study, an acoustic stimulus (50 ms, 100 dB noise) was presented alone or with a green (go) or red (no‐go) circle; in the second study, a prepulse (50 ms, 75 dB noise) was presented alone or 120 ms before the startle stimulus or circle. The startle stimulus speeded responses to the go stimuli and increased the covert false alarm rate in the no‐go condition (measured by EMG activity in the hand), although very few overt errors were made in the no‐go condition. Startle response magnitude was increased by a circle but decreased by a prepulse. The speeding of go responses caused by a startle stimulus was attenuated by the occurrence of a startle response, suggesting that an intense accessory stimulus can facilitate responding to an imperative stimulus, and that the startle response to that intense stimulus can interfere with that facilitation.     

Overcoming limitations of the ERP method with Residue Iteration Decomposition (RIDE): A demonstration in go/no‐go experiments

The usefulness of the event‐related potential (ERP) method can be compromised by violations of the underlying assumptions, for example, confounding variations of latency and amplitude of ERP components within and between conditions. Here we show how the ERP subtraction method might yield misleading information due to latency variability of ERP components. We propose a solution to this problem by correcting for latency variability using Residue Iteration Decomposition (RIDE), demonstrated with data from representative go/no‐go experiments. The overlap of N2 and P3 components in go/no‐go data gives rise to spurious topographical localization of the no‐go–N2 component. RIDE decomposes N2 and P3 based on their latency variability. The decomposition restored the N2 topography by removing the contamination from latency‐variable late components. The RIDE‐derived N2 and P3 give a clearer insight about their functional relevance in the go/no‐go paradigm.     

Differentiation of neuronal operations in latent components of event‐related potentials in delayed match‐to‐sample tasks

The goal of this study was to decompose ERPs into latent components associated with hypothetical processes of category discrimination, comparison to working memory and action‐related operations. In five variants of the delayed match‐to‐sample s1‐s2 task, instructions were varied for manipulation of the processes. The blind source separation was applied to the collection of ERPs. The category discrimination operation is attributed to three latent components with peak latencies of 130 to 170 ms, which are generated in different parts of the prestriate cortex. The comparison to working memory operation is attributed to a latent component that is generated in the temporal cortex and manifested in a positive deflection with a peak latency of 250 ms after s2. The category discrimination and comparison to working memory effects were dissociated spatially and temporally from attention and action selection effects.     

Neural correlates of successful and partial inhibitions in children: An ERP study

This experiment used event‐related potentials (ERPs) to investigate the neural processes underlying the development of response inhibition in a modified version of the go/no‐go paradigm [Cragg and Nation [2008] Developmental Science 11(6): 819–827]. N2 and P3 ERP components on correct go trials and partial and successful inhibitions were compared in 7‐ and 9‐year‐old children. A larger N2 effect on successful inhibitions was found in 9‐year‐olds compared to 7‐year‐olds at fronto‐central electrodes. N2 amplitude was positively related to behavioral performance in the 7‐year‐olds suggesting it may reflect inhibitory processes; however, this relationship was not present in the 9‐year‐olds. Age differences were also apparent in the go P3, perhaps indicating differences in stimulus processing. The no‐go P3 component was larger on successful than partial inhibitions. In contrast, there was no difference in N2 amplitude between partial and successful inhibitions. A significant difference was found in N2 latency however. This suggests that inhibitory processes are similar in both cases but initiated earlier on successful inhibitions. N2 latency was also shorter in 9‐year‐olds than 7‐year‐olds supporting an increase in the efficiency of response inhibition with age. © 2009 Wiley Periodicals, Inc. Dev Psychobiol 51: 533–543, 2009.     

Stimulus sequence context differentially modulates inhibition‐related theta and delta band activity in a go/no‐go task

Recent work suggests that dissociable activity in theta and delta frequency bands underlies several common ERP components, including the no‐go N2/P3 complex, which can better index separable functional processes than traditional time‐domain measures. Reports have also demonstrated that neural activity can be affected by stimulus sequence context information (i.e., the number and type of preceding stimuli). Stemming from prior work demonstrating that theta and delta index separable processes during response inhibition, the current study assessed sequence context in a go/no‐go paradigm in which the number of go stimuli preceding each no‐go was selectively manipulated. Principal component analysis of time‐frequency representations revealed differential modulation of evoked theta and delta related to sequence context, where delta increased robustly with additional preceding go stimuli, while theta did not. Findings are consistent with the view that theta indexes simpler initial salience‐related processes, while delta indexes more varied and complex processes related to a variety of task parameters.     

Preparing for (valenced) action: The role of differential effort in the orthogonalized go/no‐go task

Associating reward to task performance has been shown to benefit scores of cognitive functions. Importantly, this typically entails associating reward to the execution of a response, hence intertwining action‐related processes with motivational ones. However, recently, preparatory action requirements (go/no‐go) and outcome valence (reward/punishment) were elegantly separated using a cued orthogonalized go/no‐go task. Functional magnetic resonance imaging results from this task showed that typical areas of the “reward network,” like the dopaminergic midbrain and the striatum, predominantly encode action rather than valence, displaying enhanced activity when preparing for action (go) compared to inaction (no‐go). In the current study, we used ERPs to probe for differences in preparatory state related to cognitive effort in this task, which has similarly been linked to reward‐network activity. Importantly, the contingent negative variation, which is linked to effortful cognitive preparation processes during cue‐target intervals, was clearly observed in go trials but not in no‐go trials. Moreover, target‐locked ERP results (N1 and P3) suggested that attention to the target was enhanced when an action had to be performed (go trials), and typical inhibition‐related ERP components were not observed in no‐go trials, suggesting a lack of active response inhibition. Finally, feedback‐related P3 results could suggest that correct feedback was valued more in motivated go trials, again implying that more effort was required to correctly perform the task. Together, these results indicate that the anticipation of action compared to inaction simultaneously entails differences in mental effort, highlighting the need for further dissociation of these concepts.     

Automatic emotion regulation in response inhibition: The temporal dynamics of emotion counter‐regulation during a go/no‐go task

Recent behavioral studies indicate that emotion counter‐regulation automatically allocates attention to events that are opposite in the valence to the experienced emotional state. The present study explored the effect of emotion counter‐regulation on response inhibition by using ERPs in a go/no‐go paradigm. We recruited 58 subjects and randomly assigned them to either the angry priming group (watching Nanjing Massacre movie clips) or the neutral priming group (watching “mending a computer” movie clips). The behavioral results revealed that participants in the angry priming group responded significantly more accurately to go happy and no‐go angry faces than go angry and no‐go happy faces. The analyses of ERPs revealed that the amplitudes of the no‐go N2 and no‐go P3 were significantly larger for the happy faces than for the angry faces in the angry priming group. However, no such effects were found in the neutral priming group. These results suggest that highly aroused angry emotion could prompt a priority response to happy emotion stimuli and restrict the responses to angry emotion stimuli through emotion counter‐regulation.     

The two faces of avoidance: Time‐frequency correlates of motivational disposition in blood phobia

Contrary to other phobias, individuals with blood phobia do not show a clear‐cut withdrawal disposition from the feared stimulus. The study of response inhibition provides insights into reduced action disposition in blood phobia. Twenty individuals with and 20 without blood phobia completed an emotional go/no‐go task including phobia‐related pictures, as well as phobia‐unrelated unpleasant, neutral, and pleasant stimuli. Behavioral results did not indicate a phobia‐specific reduced action disposition in the phobic group. Time‐frequency decomposition of event‐related EEG data showed a reduction of right prefrontal activity, as indexed by an increase in alpha power (200 ms), for no‐go mutilation trials in the phobic group but not in controls. Moreover, theta power (300 ms) increased specifically for phobia‐related pictures in individuals with, but not without, blood phobia, irrespective of go or no‐go trial types. Passive avoidance of phobia‐related stimuli subtended by the increased alpha in the right prefrontal cortex, associated with increased emotional salience indexed by theta synchronization, represents a possible neurophysiological correlate of the conflicting motivational response in blood phobia. Through the novel use of time‐frequency decomposition in an emotional go/no‐go task, the present study contributed to clarifying the neurophysiological correlates of the overlapping motivational tendencies in blood phobia.     

The role of inhibition for working memory processes: ERP evidence from a short‐term storage task

Human working memory is the central unit for short‐term storage of information. In addition to the selection and adequate storage of relevant information, the suppression of irrelevant stimuli from the environment seems to be of importance for working memory processes. To learn more about the interplay of information uptake and inhibition of irrelevant information, the present study used ERP measures and a short‐term storage and retrieval task, in which pairs of either numbers or letters had to be compared. Random sequences of four stimuli (two numbers and two letters) were presented, with either the numbers or the letters being relevant for comparison. The analysis of ERPs to each of the four stimuli indicated more pronounced P2 and P3b amplitudes for relevant than irrelevant stimuli. In contrast, the N2 (reflecting inhibitory control) was only elicited by irrelevant stimuli. Moreover, the N2 amplitude of the second irrelevant stimulus was associated with behavioral performance, indicating the importance of inhibition of task‐irrelevant stimuli for working memory processes. In sum, the findings demonstrate the role of cognitive control mechanisms for protecting relevant contents in working memory against irrelevant information.     

Posterior brain ERP patterns related to the go/no-go task in children

Event-related potentials (ERPs) and performance correlates of inhibition of responses to no-go stimuli were investigated in 6-12-year-old children and young adults. The percent of correct responses to go stimuli was high and similar in both groups; the percent of false alarm errors to no-go was significantly higher in children. Effective inhibition of responses to no-go stimuli was elucidated by a negative component of ERPs, the frontal-central N2, with peak latency 230-430 ms after stimulus onset. In adults, N2 was larger to no-go than to go stimuli, regardless of stimulus frequency. This effect was more prominent in tasks with high (25% no-gos and 75% gos), than with low (75% no-gos and 25% gos) inhibitory demand. In children, the parietal N2 was generally larger to rare than to frequent stimuli, and it was more specifically related to inhibition. The analysis of the relationship of no-go N2 to the inhibitory content of stimuli, probability of stimuli, and the contextual task difficulty suggests that child/adult differences in behavioral responses and ERPs may be related to both the immaturity of the fronto-parietal cortical-cortical network and to different task strategies.     

Object‐substitution masking modulates spatial attention deployment and the encoding of information in visual short‐term memory: Insights from occipito‐parietal ERP components

If object‐substitution masking (OSM) arises from mask representations replacing target representations, OSM should impede the formation of representations in visual short‐term memory (VSTM). We utilized event‐related potentials to examine the effect of OSM on target processing. An N2pc was observed on trials with delayed‐offset masks, indicating that focused attention was directed to the target. The sustained posterior contralateral negativity (SPCN), an index of VSTM storage, was observed in delayed‐offset trials only on trials with correct responses. This supports the hypothesis that inaccurate performance on delayed‐offset trials arises from a failure to encode the target in VSTM. On co‐termination trials, accuracy was high and neither the N2pc nor SPCN was observed. This indicates that, in the absence of masking, the task was accomplished by maintaining a diffuse attentional state that enabled the joint encoding of the potential target items.     

Neuronal responses to a delayed-response delayed-reward go/nogo task in the monkey posterior insular cortex

Anatomical connections of the insular cortex suggest its involvement in cognition, emotion, memory, and behavioral manifestation. However, there have been few neurophysiological studies on the insular cortex in primates, in relation to such higher cognitive functions. In the present study, neural activity was recorded from the monkey insular cortex during performance of a delayed-response delayed-reward go/nogo task. In this task, visual stimuli indicating go or nogo responses associated with reward (reward trials) and with no reward (no-reward trials) were presented after eye fixation. In the reward trials, the monkey was required to release a button during presentation of the 2nd visual stimuli after a delay period (delay 1). Then, a juice reward was delivered after another delay (delay 2). The results indicated that the neurons responding in each epoch of the task were topographically localized within the insular cortex, consistent with the previous anatomical studies indicating topographical distributions of afferent inputs from other subcortical and cortical sensory areas. Furthermore, some insular neurons 1) nonspecifically responded to the visual cues and during fixation; 2) responded to the visual cues predicting reward and during the delay period before reward delivery; 3) responded differentially in go/nogo trials during the delay 2; and 4) responded around button manipulation. The observed patterns of insular-neuron responses and the correspondence of their topographical localization to those in previous anatomical studies suggest that the insular cortex is involved in attention- and reward-related functions and might monitor and integrate activities of other brain regions during cognition and behavioral manifestation.     

One‐year developmental stability and covariance among oddball,novelty, go/no‐go,and flanker event‐related potentials in adolescence: A monozygotic twin study

ERP measures may index genetic risk for psychopathology before disorder onset in adolescence, but little is known about their developmental rank‐order stability during this period of significant brain maturation. We studied ERP stability in 48 pairs of identical twins (age 14–16 years) tested 1 year apart. Trial‐averaged voltage waveforms were extracted from electroencephalographic recordings from oddball/novelty, go/no‐go, and flanker tasks, and 16 amplitude measures were examined. Members of twin pairs were highly similar, whether based on ERP amplitude measures (intraclass correlation [ICC] median = .64, range = .44–.86) or three factor scores (all ICCs ≥ .69) derived from them. Stability was high overall, with 69% of the 16 individual measures generating stability coefficients exceeding .70 and all factor scores showing stability above .75. Measures from 10 difference waveforms calculated from paired conditions within tasks were also examined, and were associated with lower twin similarity (ICC median = .52, .38–.64) and developmental stability (only 30% exceeding .70). In a supplemental analysis, we found significant developmental stability for error‐related negativity (range = .45–.55) and positivity (.56–.70) measures when average waveforms were based on one or more trials, and that these values were equivalent to those derived from averages using the current field recommendation, which requires six or more trials. Overall, we conclude that the studied brain measures are largely stable over 1 year of mid‐ to late adolescence, likely reflecting familial etiologic influences on brain functions pertaining to cognitive control and salience recognition.     

An ERP study of cross‐modal rhyming: Influences of phonology and orthography

In a cross‐modal rhyming study with visual pseudoword primes and auditory word targets, we found a typical ERP rhyming effect such that nonrhyming targets elicited a larger N400/N450 than rhyming targets. An orthographic effect was also apparent in the same 350‐ to 600‐ms epoch as the phonological effect: The rhyming effect for targets with rime orthography that did not match their primes' (e.g., tain‐“sane”) was smaller over the left hemisphere than the rhyming effect for targets with rime orthography that did match their primes' (e.g., nain‐“gain”), although the spellings of the auditory word targets were never explicitly shown. Our results indicate that this cross‐modal ERP rhyming effect indexes both phonological and orthographic processing—for auditory stimuli for which no orthography is presented in the task. This pattern of findings is consistent with the notion of coactivation of sublexical orthography and phonology in fluent adult readers as they both read and listen.     

Cue‐locked lateralized components in a tactile spatial attention task: Evidence for a functional dissociation between ADAN and LSN

ERP studies investigating the control processes responsible for spatial orienting in touch have consistently observed that the anterior directing attention negativity (ADAN) elicited by an attention‐directing cue is followed by a sustained negativity contralateral to the cued hand. Recent evidence suggested that the later negativity, labeled late somatotopic negativity (LSN), might reflect distinct neurocognitive processes from those associated with the ADAN. To investigate the functional meaning of the ADAN and LSN components, we measured ERPs elicited by bilateral tactile cues indicating to covertly shift tactile attention to the left or right hand. Participants performed two spatial attention tasks that differed only for the difficulty of the target/nontarget discrimination at attended locations. The LSN but not the ADAN was sensitive to our experimental manipulation of task difficulty, suggesting that this component might reflect sensory‐specific preparatory processes prior to a forthcoming tactile stimulus.     

Using trial‐level data and multilevel modeling to investigate within‐task change in event‐related potentials

EEG data, and specifically the ERP, provide psychologists with the power to examine quickly occurring cognitive processes at the native temporal resolution at which they occur. Despite the advantages conferred by ERPs to examine processes at different points in time, ERP researchers commonly ignore the trial‐to‐trial temporal dimension by collapsing across trials of similar types (i.e., the signal averaging approach) because of constraints imposed by repeated measures ANOVA. Here, we present the advantages of using multilevel modeling (MLM) to examine trial‐level data to investigate change in neurocognitive processes across the course of an experiment. Two examples are presented to illustrate the usefulness of this technique. The first demonstrates decreasing differentiation in N170 amplitude to faces of different races across the course of a race categorization task. The second demonstrates attenuation of the ERN as participants commit more errors within a task designed to measure implicit racial bias. Although the examples presented here are within the realm of social psychology, the use of MLM to analyze trial‐level EEG data has the potential to contribute to a number of different theoretical domains within psychology.