Different slopes for different folks: Alpha and delta EEG power predict subsequent video game learning rate and improvements in cognitive control tasks

We hypothesized that control processes, as measured using electrophysiological (EEG) variables, influence the rate of learning of complex tasks. Specifically, we measured alpha power, event‐related spectral perturbations (ERSPs), and event‐related brain potentials during early training of the Space Fortress task, and correlated these measures with subsequent learning rate and performance in transfer tasks. Once initial score was partialled out, the best predictors were frontal alpha power and alpha and delta ERSPs, but not P300. By combining these predictors, we could explain about 50% of the learning rate variance and 10%–20% of the variance in transfer to other tasks using only pretraining EEG measures. Thus, control processes, as indexed by alpha and delta EEG oscillations, can predict learning and skill improvements. The results are of potential use to optimize training regimes.     

Comparing P300 modulations: Target‐to‐target interval versus infrequent nontarget‐to‐nontarget interval in a three‐stimulus task

This study examined temporal determinants of the P300 component of the ERP in a three‐stimulus visual oddball task. Frequent standards, with equiprobable targets and infrequent nontargets, were utilized. We tested whether the infrequent nontarget‐to‐nontarget interval (infrequent NNI) influences P300 amplitudes and latencies analogously to the target‐to‐target interval (TTI). EEG was recorded from 27 participants, and response time and P300 effects of TTIs and infrequent NNIs were assessed. Increases in TTI augmented target P300 amplitudes and decreased latencies and response times. However, this modulation of P300 amplitude was weak for manipulations of infrequent NNI. P300 latencies increased initially before decreasing across infrequent NNI levels. Together, these findings support the notion that the P300 has an underlying temporal mechanism that is modulated by motivationally significant events. Theoretical implications are discussed.     

Event‐related EEG time‐frequency PCA and the orienting reflex to auditory stimuli

We recently reported an auditory habituation series with counterbalanced indifferent and significant (counting) instructions. Time‐frequency (t‐f) analysis of electrooculogram‐corrected EEG was used to explore event‐related synchronization (ERS)/desynchronization (ERD) in four EEG bands using arbitrarily selected time epochs and traditional frequency ranges. ERS in delta, theta, and alpha, and subsequent ERD in theta, alpha, and beta, showed substantial decrement over trials, yet effects of stimulus significance (count vs. no‐task) were minimal. Here, we used principal components analysis (PCA) of the t‐f data to investigate the natural frequency and time combinations involved in such stimulus processing. We identified four ERS and four ERD t‐f components: six showed decrement over trials, four showed count > no‐task effects, and six showed Significance × Trial interactions. This increased sensitivity argues for the wider use of our data‐driven t‐f PCA approach.     

An ERP study of age‐related differences in the central cost of interlimb coordination

The study investigated event‐related EEG potentials during concurrent performance of interlimb coordination and visual oddball tasks by younger and older adults. Coordination task difficulty was equated between age groups by allowing participants to perform the task at self‐determined frequencies. The amplitude of the P3b component of the event‐related potentials (ERPs) elicited by visual task targets showed a different pattern across midline sites (Fz, Cz, Pz) for younger and older adults. While younger adults showed a parietal maximum, P3b amplitudes in older adults did not differ across midline site, with lower amplitudes at central and parietal sites than younger adults but higher amplitude at the frontal site. Younger adults also had significantly shorter P3b latency than older adults. The results suggest that older adults may rely more on cognitive control of their movements than younger adults.     

Electrophysiological revelations of trial history effects in a color oddball search task

In visual oddball search tasks, viewing a no‐target scene (i.e., no‐target selection trial) leads to the facilitation or delay of the search time for a target in a subsequent trial. Presumably, this selection failure leads to biasing attentional set and prioritizing stimulus features unseen in the no‐target scene. We observed attention‐related ERP components and tracked the course of attentional biasing as a function of trial history. Participants were instructed to identify color oddballs (i.e., targets) shown in varied trial sequences. The number of no‐target scenes preceding a target scene was increased from zero to two to reinforce attentional biasing, and colors presented in two successive no‐target scenes were repeated or changed to systematically bias attention to specific colors. For the no‐target scenes, the presentation of a second no‐target scene resulted in an early selection of, and sustained attention to, the changed colors (mirrored in the frontal selection positivity, the anterior N2, and the P3b). For the target scenes, the N2pc indicated an earlier allocation of attention to the targets with unseen or remotely seen colors. Inhibitory control of attention, shown in the anterior N2, was greatest when the target scene was followed by repeated no‐target scenes with repeated colors. Finally, search times and the P3b were influenced by both color previewing and its history. The current results demonstrate that attentional biasing can occur on a trial‐by‐trial basis and be influenced by both feature previewing and its history.     

The effects of response sharing and stimulus presentation frequency on event‐related potentials in an auditory oddball paradigm

An experimental model for investigating the processes involved in reacting to unpredictable events is the oddball paradigm. We investigated how the commonality or independence of response options (i.e., many‐to‐one vs. one‐to‐one stimulus‐response mappings) influences processing in an auditory oddball paradigm. Participants performed a discrimination task with two one‐to‐one and one two‐to‐one mappings. The pattern of conflict‐ and oddball‐related N2 event‐related potentials suggest that information that would allow correct responding is represented at the latency of the N2. Integration of this information takes place only by the latency of P3b, and longer reaction times to rare stimuli are probably due to processes preventing the utilization of this information. We also suggest that, in the given task context, conflict‐related N2 may reflect the number of alternative stimuli leading to alternative response options.     

Mapping attention during gameplay: Assessment of behavioral and ERP markers in an auditory oddball task

Video games are enjoyed most when the level and speed of the game match the players' skills. An optimal balance between challenges and skills triggers the subjective experience of “flow,” a focused motivation leading to a feeling of spontaneous joy. The present research investigates the behavioral and neural correlates of a paradigm aimed to assess the players' subjective experience during gameplay. Attentional engagement changes were assessed first at the behavioral level and in a second stage by means of EEG recordings. An auditory novelty oddball paradigm was implemented as a secondary task while subjects played in three conditions: boredom, frustration, and flow. We found higher reaction times and error rates in the flow condition. In a second stage, EEG time domain analysis revealed a significantly delayed response‐locked frontocentral negative deflection during flow, likely signaling the reallocation of attentional resources. Source reconstruction analyses showed that the brain regions responsible for the genesis of this negativity were located within the medial frontal cortex. Frequency domain analyses showed a significant power increase only in the alpha band for the flow condition. Our results showed that this alpha power enhancement was correlated with faster reaction times. This suggests that frontal alpha changes recorded as maximal at the midfrontal lines during flow might be related to inhibitory top‐down cognitive control processes.     

Category‐based inhibition of focused attention across consecutive trials

The distractor previewing effect (DPE) refers to the behavioral phenomenon that search times increase for oddball targets containing features recently associated with the absence of a target. Previous work using a color‐oddball search task showed that the DPE covaried with the N2pc component of the event‐related potential (an index of attention allocation) but not with other components, suggesting that the DPE reflects shifts in attentional sets. We sought to determine whether the previous results could generalize to a category‐oddball search task. Results showed that the DPE co‐occurred with N2pc effects in about 60% of the participants, and the DPE occurred with no N2pc effects in the rest of the participants. These results support a domain‐general, attention‐based account of the DPE, but also suggest that the attention‐based DPE account requires some modifications.     

On utilizing uncertainty information in template‐based EEG‐fMRI ballistocardiogram artifact removal

The correction of ballistocardiogram artifacts in simultaneous EEG‐fMRI often yields unsatisfactory results. To improve the signal‐to‐noise ratio (SNR) of results, we inferred EEG signal uncertainty from postcorrection artifact residuals and computed the uncertainty‐weighted mean of ERPs. Using an uncertainty‐weighted mean significantly and consistently reduced both inter‐ and intrasubject SEM in the analysis of auditory evoked responses (AER, indicated by the N1‐P2 complex) and in the effects of an auditory oddball paradigm (N1‐P3 complex, standard‐deviant difference). SNR increased by 3% on average for the AER amplitude (intrasubject) and 17% on average for the auditory oddball ERP (intersubject). This demonstrates that weighting by uncertainty complements existing artifact correction algorithms to increase SNR in ERPs. More specifically, it is an efficient method to utilize seemingly corrupt (difficult‐to‐correct) EEG data that might otherwise be discarded.     

Poststimulus EEG spectral analysis and P300: attention, task, and probability

Event-related potentials (ERPs) were elicited with auditory stimuli, and spectral analysis was performed on the poststimulus electroencephalographic (EEG) activity to assess how variables that influence the P300 affect spectral parameters of the resultant ERP. In Experiment 1, a no-stimulus condition was compared with a single repeated tone that was either ignored or counted. In Experiment 2, an auditory oddball paradigm was used in which the subject ignored all stimuli, counted only the target, or counted both the target and the standard stimuli in different conditions. In Experiment 3, stimulus probability was manipulated in separate conditions (.20, .50, .80), with the subject required to count the target stimulus. Delta and theta band spectral power increased whenever P300 amplitude increased. However, as the attentional requirements increased across tasks, alpha-1 and alpha-2 power and mean frequency increased. The findings indicate that auditory stimulus processing modulates the EEG more than just by adding ERP components to the epoch.     

Attentional capture by size singletons is determined by top-down search goals

The question whether attentional capture by salient visual stimuli is driven by bottom-up salience or is contingent on top-down task set is still under dispute. We show that the ability of size singletons to capture attention is determined by current search goals. Participants searched for small or large target singletons among medium-size distractors. Attentional capture by small or large size singleton cues that preceded target search displays was reflected by spatial cueing effects and N2pc components. These effects were observed only when these cues matched the current target-defining feature, but not for physically identical but mismatching cues. Results demonstrate that attentional capture by size singletons is not driven by bottom-up salience, but is controlled by feature-specific task settings.     

The temporal locus of the interaction between working memory consolidation and the attentional blink

An increase in concurrent working memory load has been shown to amplify the attentional blink. The present study investigated the temporal locus of this phenomenon, by using a dual rapid serial visual presentation paradigm that enabled the measurement of lateralized event‐related potentials. The P3 component was shown to be affected by both working memory load and the lag between the target stimuli, consistent with current models of temporal attention and a functional explanation of the P3 in terms of memory consolidation. P3 amplitude was reduced for short target lags and high memory loads. The P2 component was affected by lag only, and not memory load. Importantly, the N2pc component was modulated also by both lag and memory load. The results showed that early attentional processing (as marked by the N2pc) was suppressed by increased involvement of working memory, a phenomenon not well predicted by many current theories of temporal attention.     

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.     

Age-related differences in attention to novelty among cognitively high performing adults

Age-related differences in attention to novel events were studied in well-matched, cognitively high performing old, middle-aged and young subjects. Event-related potentials were recorded during a visual novelty oddball task in which subjects controlled viewing durations that served as a behavioral measure of attentional allocation. All age groups had a larger P3 amplitude and longer viewing duration to novel than to standard stimuli, with no age-related differences in the magnitude of these effects, indicating old individuals were as engaged by the processing of novelty as younger adults. Old subjects had a larger, more anteriorly distributed P3 component to novels and standards. The increased P3 amplitude differs from prior reports of a diminished P3 response with processes, including aging, that have a potentially deleterious impact on the brain. We hypothesise that cognitively high performing old individuals successfully manage the task by relying on additional neural resources and perhaps more effortful frontal activity than their younger counterparts.     

Brain electrical activity signatures during performance of the Multisource Interference Task

The Multisource Interference Task (MSIT) was developed to test cognitive control in normal and pathological conditions and has become a reliable tool for exploring the integrity of cingulo‐frontal‐parietal cognitive/attentional networks in fMRI studies. Analysis of EEG recordings made during performance of the MSIT may provide additional information about the temporal dynamics of cognitive control. However, this has not yet been investigated in depth. In this study, we analyzed the ERPs and carried out time‐frequency decomposition of EEG recorded during control and interference conditions of the MSIT. The N2 ERP component and midfrontal theta power (both considered neural signatures of conflict processing) were significantly larger in interference than in control trials. Theta also showed higher phase synchronization between midfrontal and right frontolateral scalp locations in the interference condition, supporting the view that this frequency band entrains additional brain resources when a need for greater control arises. In interference trials, we also observed longer P3 latency, larger P3 amplitude, and greater reduction of posterior alpha (modulations related to allocation of attentional resources), in addition to a greater reduction of central beta power (related to motor preparation). In conclusion, the MSIT reliably modulated brain electrical activity related to cognitive control and attention. The EEG indices obtained during the performance of this task may be useful for exploring the functioning of cognitive/attentional networks in healthy and clinical populations.     

Novelty detection is enhanced when attention is otherwise engaged: an event-related potential study

Novel stimuli are detected and evaluated quickly, suggesting that processing them is a priority for the brain. In the present study, the effects of attention on this early visual novelty processing were investigated in two experiments using the event-related potential (ERP) technique. In the first experiment, participants performed two tasks that varied in the amount of attention available for novel stimuli. In the Visual Oddball task, participants responded to an infrequent target presented among standard and novel stimuli. In the Working Memory task, participants saw the same stimuli, but they could ignore them. Instead, participants had to keep six letters in working memory and report one of these letters at the end of the trial; attention was thus maximally allocated away from the visual oddball stimuli. In line with attention being fully occupied in the Working Memory task, the P3a to the visual oddball stimuli was smaller in the Working Memory than in the Visual Oddball task. In contrast, the anterior N2 component to task-irrelevant stimuli was enhanced in the Working Memory task. These findings suggest that the initial detection of novel stimuli is enhanced (large anterior N2) when few attentional resources are available, which is inconsistent with earlier findings that if anything, the N2 is enhanced by attention. In a second experiment, a condition was added in which working memory load was low, but visual oddball stimuli were task-irrelevant. Results from this experiment showed that while the reduction in P3a amplitude was due to task irrelevance, the enhanced anterior N2 was linked to a high working memory load. This suggests that novelty detection is enhanced when attention is otherwise engaged.     

Temporal attention shortens perceptual latency: a temporal prior entry effect

The prior entry hypothesis of attention holds that attended stimuli are perceived earlier than unattended stimuli. Whereas this speeding of perceptual processing has been repeatedly demonstrated for spatial attention, it has not been reported within the temporal domain. To fill this gap, we tested whether temporal attention accelerates auditory perceptual processing by employing event-related potentials as on-line indicators of perceptual processing. In a modified oddball paradigm, we presented a single tone in each trial, either a frequent standard tone or an infrequent deviant or target tone. Temporal attention to tones was manipulated via constant foreperiods. We observed that the latency of the N2, an event-related potential reflecting perceptual processing, is shortened by temporal attention. This result provides first evidence for the idea that temporal attention accelerates perceptual processing as suggested by the prior entry hypothesis.     

The absence of a visual stimulus can trigger task-set-independent attentional capture

We investigated whether the absence of one item in a regularly spaced visual array (gap cue) captures attention in a task-set-independent fashion. Participants searched for a large target among medium-size distractors (size task) or a red target among gray distractors (color task). Target arrays were preceded by uninformative cue arrays that contained a color singleton or a gap cue. The N2pc component was measured as an index of attentional capture. Color singleton cues captured attention only in the color task, but gap cues captured attention in both tasks. For cue arrays containing a color singleton and a gap cue on opposite sides, an N2pc was triggered by the color singleton in the color task. The absence of an item in a regular array triggered task-set-independent attentional capture when it was the only unique display feature, but not when a competing set-matching singleton was simultaneously present.     

Fast temporal event integration in the visual domain demonstrated by event‐related potentials

Four experiments are reported that investigated visual event integration by using a variant of the missing element paradigm. Good performance on this task depends on whether two brief successive stimulus displays are perceived as (or integrated into) one single event. We replicated the classic finding of greater accuracy with shorter duration of the first stimulus and ruled out an attention‐related account thereof. In a subsequent electrophysiological experiment we found that successful event integration increased the amplitude of the N1, N2, and late P3 components of the event‐related potential and decreased early P3 amplitude. No effect on the P1 was observed. The results provided evidence for an early onset of event integration in time and demonstrated the existence of electrophysiological markers of episodic integration. The implications of these results are related to studies on feature‐specific integration and early attentional processes.     

Single bouts of exercise selectively sustain attentional processes

This study examined how single bouts of exercise may differentially modulate neuroelectric correlates of attentional orienting and processing. Using a within‐participants design, ERPs and task performance were assessed in response to a perceptually challenging three‐stimulus oddball task prior to and following a bout of exercise or seated rest during two separate, counterbalanced sessions. Findings revealed that, following a single bout of exercise, attentional processing was sustained relative to pretest whereas prolonged sitting resulted in attentional decrements. Focal attention resulting from attentional orienting, in contrast, does not appear to be sensitive to the influences of single bouts of physical activity. These findings suggest that acute exercise‐induced changes in cognition do not originate from an overall modulation of attention but instead are specific to aspects of attentional processing.