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Mu desynchronization is the attenuation of EEG power in the alpha frequency range recorded over central scalp locations thought to reflect motor cortex activation. Mu desynchronization during observation of an action is believed to reflect mirroring system activation in humans. However, this notion has recently been questioned because, among other reasons, the potential contamination of mu rhythm and occipital alpha activity induced by attention processes following presentation of visual stimuli in observation conditions. This study examined the validity of mu desynchronization as a measure of mirroring system activation in infants and further investigated the pattern of functional connectivity between the central and occipital regions during execution and observation of movement. EEG was recorded while 46 9-month-old infants executed grasping actions and observed an experimenter grasping. Current source density (CSD) was applied to EEG data and, time-frequency and connectivity analyses were performed in CSD transformed data. Mu desynchronization was evident over central regions during both execution and observation of movements. Independent alpha desynchronization over occipital region was also present in both conditions. The connectivity analyses revealed that central-occipital areas were functionally more connected compared to other areas of the brain during observation of movements. Collectively, the results demonstrate the validity of mu desynchronization as an index of infant mirroring system activity and support the proposal of a functional connection between distinct mirroring and attention processes during observation of action.

Behavioral inhibition (BI) is an early temperamental precursor of anxiety disorders, characterized by withdrawal from novel situations. Some but not all young children with BI go on to display anxiety disorders. Neural correlates, such as frontal alpha asymmetry or event-related negativity (ERN), could moderate the relations between early BI and later anxiety. The goal of this longitudinal study was to test frontal alpha asymmetry as a potential moderator of the relation between BI and later anxiety, and of the relation between BI and the social-effect ERN. 100 children were assessed for BI at ages 2 and 3, and we collected EEG during resting state and the social Flanker task at age 12. Frontal alpha asymmetry did not correlate with BI or anxiety, nor did it moderate the relation between early BI and later anxiety. However, frontal alpha asymmetry did moderate the relation between BI and the social-effect ERN. This suggests that, in adolescents who previously manifested BI, a pattern of resting EEG associated with avoidance predicts hypersensitivity to errors in a social context.

Empirical research demonstrates that when the time following error commission is constrained, subsequent sensory processing can be impaired (Buzzell et al., 2017). This reduction in sensory processing is presumably due to a bottleneck for cognitive resources produced by an overlap between error processing and subsequent stimulus processing. This finding suggests that the system dedicated to improving task performance can actually sometimes be the source of performance failures. Although this finding established that data-limited errors lead to a reduction in sensory processing at short response stimulus intervals (RSIs), it remains unclear if the relationship between error processing and subsequent sensory processing can be modulated by speeded-response errors. In the present study, event-related potentials and behavioral measures were recorded while participants performed a modified version of a Simon task, in which RSI duration was varied. We found that sensory processing, indexed by the P1 component, was reduced following errors at short (200–533 ms), but not long (866–1200 ms), RSIs. Moreover, the magnitude of error processing differentially influenced subsequent sensory processing as a function of RSI. However, whereas prior work demonstrated that the error positivity (Pe) modulated sensory processing on the subsequent trial, only the error-related negativity (ERN) did so within the Simon task. This suggests that although both data-limited errors and speeded-response errors can impact subsequent sensory processing, different stages of error processing appear to mediate this phenomenon.

The temperament of behavioral inhibition (BI) is classically defined based on behavioral observations of a child’s fear and avoidance of novelty. Such behavioral observations have proven powerful in identifying individual differences in temperament, and such differences have been shown to be predictive of later developmental outcomes, particularly levels of shyness or anxiety. However, behavioral observations alone leave open several questions, including: (1) How does the brain of a child high in behavioral inhibition differ from a child low in behavioral inhibition? (2) Which domains of cognition are directly related to variation in behavioral inhibition? (3) For domains of cognition not directly related to behavioral inhibition, how do individual differences interact with behavioral inhibition to predict later risk for anxiety? Examining these questions, research has demonstrated that individual differences in the child’s ability to monitor and control their behaviors when trying to complete a goal, a set of processes known as “cognitive control,” may change the likelihood of a child high in behavioral inhibition developing later anxiety. However, relations between behavioral inhibition and cognitive control have been inconsistent across studies. Here, we leverage a cognitive neuroscience framework to review studies that have investigated the interrelations between behavioral inhibition, cognitive control, and anxiety. Critically, we separate cognitive control into the subdomains of “monitoring” and “control instantiation” as well as further parse control instantiation based on domain and time course. In making these distinctions, we show that there is consistent evidence that the behavioral inhibition phenotype is directly related to increased monitoring, but not levels of control instantiation. However, behavioral inhibition is related to the time course of control, and both monitoring and control interact with behavioral inhibition to predict increased risk for the development of anxiety. We suggest that continued progress in understanding the interrelations between behavioral inhibition and cognitive control will require a similar framework that separates cognitive control into subdomains.

ObjectiveBehavioral inhibition (BI) is a temperament identified in early childhood that is a risk factor for later social anxiety. However, mechanisms underlying the development of social anxiety remain unclear. To better understand the emergence of social anxiety, longitudinal studies investigating changes at behavioral neural levels are needed.MethodBI was assessed in the laboratory at 2 and 3 years of age (N= 268). Children returned at 12 years, and an electroencephalogram was recorded while children performed a flanker task under 2 conditions: once while believing they were being observed by peers and once while not being observed. This methodology isolated changes in error monitoring (error-related negativity) and behavior (post-error reaction time slowing) as a function of social context. At 12 years, current social anxiety symptoms and lifetime diagnoses of social anxiety were obtained.ResultsChildhood BI prospectively predicted social-specific error-related negativity increases and social anxiety symptoms in adolescence; these symptoms directly related to clinical diagnoses. Serial mediation analysis showed that social error-related negativity changes explained relations between BI and social anxiety symptoms (n= 107) and diagnosis (n= 92), but only insofar as social context also led to increased post-error reaction time slowing (a measure of error preoccupation); this model was not significantly related to generalized anxiety.ConclusionResults extend prior work on socially induced changes in error monitoring and error preoccupation. These measures could index a neurobehavioral mechanism linking BI to adolescent social anxiety symptoms and diagnosis. This mechanism could relate more strongly to social than to generalized anxiety in the peri-adolescent period.

Recent neuroimaging work has demonstrated that the ventral striatum (VS) encodes confidence in perceptual decisions. However, it remains unclear whether perceptual uncertainty can signal the need to adapt behavior (such as by responding more cautiously) and whether such behavioral changes are related to uncertainty-dependent activity within the VS. Changes in response strategy have previously been observed following errors and are associated with both medial frontal cortex (MFC) and VS, two components of the performance-monitoring network. If uncertainty can elicit changes in response strategy (slowing), then one might hypothesize that these changes rely on the performance-monitoring network. In the present study, we investigated the link between perceptual uncertainty and task-related behavioral adaptations (response slowing and accuracy increases), as well as how such behavioral changes relate to uncertainty-dependent activity within MFC and VS. Our participants performed a two-choice perceptual decision-making task in which perceptual uncertainty was reported on each trial while behavioral and event-related functional magnetic resonance imaging data were collected. Analysis of the behavioral data revealed that uncertain (but correct) responses led to slowing on subsequent trials, a phenomenon that was positively correlated with increased accuracy. Critically, post-uncertainty slowing was negatively correlated with the VS activity elicited by uncertain responses. In agreement with previous reports, increases in MFC activation were observed for uncertain responses, although MFC activity was not correlated with post-uncertainty slowing. These results suggest that perceptual uncertainty can serve as a signal to adapt one's response strategy and that such behavioral changes are closely tied to the VS, a key node in the performance-monitoring network.

INTRODUCTION Adequate evaluation of novel tobacco products must include investigation of consumers' psychological response to such products. Traditionally, subjective scales of product liking have been used to assess consumer acceptability of tobacco products. However, subjective scales may miss cognitive changes that can only be captured by direct neurophysiological assessment. The present investigation explored the viability of using electroencephalography (EEG), in combination with traditional subjective measures, to assess consumer acceptability of five smokeless tobacco products. Given previous work linking product liking to arousal/attentional (executive function) enhancement, we focused on EEG measures of attention/arousal to objectively characterize cognitive changes associated with tobacco product use. METHODS During five separate laboratory visits, smokeless tobacco users used Verve discs, Ariva dissolvables, Skoal snuff, Camel snus, or Nicorette lozenges. The N2 and P3b event-related potential components elicited by an oddball task were used to index attentional changes before/after product usage. Additionally, resting state alpha band EEG activity was analyzed before/after product usage to index cortical arousal. RESULTS Although analyses of the subjective results provided limited inference, analyses of the electrophysiological measures, particularly the alpha suppression measure, revealed robust differences between products. Skoal elicited significantly enhanced alpha suppression compared to all four other products tested. Additionally, alpha suppression was found to correlate positively with subjective measures of satisfaction and psychological reward, but was unrelated to perceived aversion. CONCLUSIONS The present results provide evidence that electrophysiological measures can yield important insights into consumer acceptability of novel tobacco products and are a valuable complement to subjective measures. IMPLICATIONS This study is the first to employ a combination of electrophysiological measures and traditional subjective assays in order to assess the consumer acceptability of smokeless tobacco products. The results highlight the importance of adopting a multidimensional/multi-method approach to studying the consumer acceptability of tobacco products.

Electroencephalography (EEG) has the prospect of providing a means to gauge operator workload in a manner that does not intrude on the task being performed. Specifically, it has been proposed that the technique could be used as a method to speed the learning of a task, by adjusting the task to suit the state of the learner. The present study recorded EEG while participants performed a simulated Unmanned Aerial Vehicle (UAV) reconnaissance task. Analysis of power in three EEG frequency bands of interest found differences between the types of task being performed; however more complex analysis may be necessary to discern levels of difficulty within the task.

Processing feedback from the environment is an essential function during development to adapt behavior in advantageous ways. One measure of feedback processing, the feedback negativity (FN), is an event-related potential (ERP) observed following the presentation of feedback. Findings detailing developmental changes in the FN have been mixed, possibly due to limitations in traditional ERP measurement methods. Recent work shows that both theta and delta frequency activity contribute to the FN; utilizing time-frequency methods to measure change in power and phase in these frequency bands may provide more accurate representation of feedback processing development in childhood and adolescence. Here, we employ time-frequency (TF) power and inter-trial phase synchrony measures, in addition to conventional time-domain ERP methods, to examine the development of feedback processing in the theta (4-7 Hz) and delta (.1-3 Hz) bands throughout adolescence. A sample of 54 females (8-17 years old) completed a gambling task while electroencephalogram (EEG) was recorded. As expected, time-domain ERP amplitudes showed no association with age. In contrast, significant effects were observed for the time-frequency measures, with theta power decreasing with age and delta power increasing with age. For inter-trial phase synchrony, delta synchrony increased with age, while age-related changes in theta synchrony differed for gains and losses. Collectively, these findings highlight the importance of considering time-frequency dynamics when exploring how the processing of feedback develops through late childhood and adolescence. In particular, the role of delta band activity and theta synchrony appear central to understanding age-related changes in the neural response to feedback.

Gaze following occurs automatically in social interactions, but the degree to which we follow gaze strongly depends on whether an agent is believed to have a mind and is therefore socially relevant for the interaction. The current paper investigates whether the social relevance of a robot can be manipulated via its physical appearance and whether there is a linear relationship between appearance and gaze following in a counter-predictive gaze cueing paradigm (i.e., target appears with a high likelihood opposite of the gazed-at location). Results show that while robots are capable of inducing gaze following, the degree to which gaze is passively followed does not linearly decrease with physical human-likeness. Rather, the relationship between appearance and gaze following is best described by an inverted u-shaped pattern, with automatic cueing effects (i.e., attending to the cued location) for agents of mixed human-likeness and reversed cueing effects (i.e., attending to the predicted location) for agents of either full human-likeness (100% human) or full robot-likeness (100% robot). The results are interpreted with regard to cognitive resource theory and design implications are discussed.

Recent work has demonstrated that the occipital–temporal N1 component of the ERP is sensitive to the difficulty of visual discrimination, in a manner that cannot be explained by simple differences in low-level visual features, arousal, or time on task. These observations provide evidence that the occipital–temporal N1 component is modulated by the application of top–down control. However, the timing of this control process remains unclear. Previous work has demonstrated proactive, top–down modulation of cortical excitability for cued spatial attention or feature selection tasks. Here, the possibility that a similar top–down process facilitates performance of a difficult stimulus discrimination task is explored. Participants performed an oddball task at two levels of discrimination difficulty, with difficulty manipulated by modulating the similarity between target and nontarget stimuli. Discrimination processes and cortical excitability were assessed via the amplitude of the occipital–temporal N1 component and prestimulus alpha oscillation of the EEG, respectively. For correct discriminations, prestimulus alpha power was reduced, and the occipital–temporal N1 was enhanced in the hard relative to the easy condition. Furthermore, within the hard condition, prestimulus alpha power was reduced, and the occipital–temporal N1 was enhanced for correct relative to incorrect discriminations. The generation of ERPs contingent on relative prestimulus alpha power additionally suggests that diminished alpha power preceding stimulus onset is related to enhancement of the occipital–temporal N1. As in spatial attention, proactive control appears to enhance cortical excitability and facilitate discrimination performance in tasks requiring nonspatial, feature-based attention, even in the absence of competing stimulus features.

Impaired cognitive control has been proposed as a hallmark of nicotine dependence and is thought to arise, in part, from synaptic alterations in anterior cingulate cortex (ACC), a primary component of the dopamine reward pathway. The N2 component of the event-related potential (ERP) appears to index a cognitive control process in paradigms such as the visual go/no-go task. Moreover, as dipole-modeling has suggested that the neural generator of the N2 component can be localized to the ACC, this component may prove useful for investigating impairments of cognitive control in smokers. Given conflicting reports of whether the N2 is reduced in smokers (as compared to non-smoker controls), the current study further examined the suitability of this component as an index for impaired cognitive control in smokers. Smokers and non-smokers performed a visual go/no-go task while electroencephalogram (EEG) was recorded. As predicted, the no-go N2 of smokers was significantly smaller than that of non-smoker controls, while the no-go P3 did not differ between groups. Importantly, behavioral performance (reaction time and accuracy) did not differ between smokers and nonsmokers, which might reflect the low levels of nicotine dependence (assessed by the Fagerstrom test) in our sample. The observed N2 modulation in the absence of behavioral impairments provides evidence for the utility of the N2 component as a sensitive measure of impaired cognitive control in smokers, even in those with low levels of nicotine dependence.

Recent work has identified an event-related potential (ERP) component, the incongruency negativity (Ninc), which is sensitive to auditory Stroop conflict processing. Here, we investigated how this index of conflict processing is influenced by individual differences in cognitive style. There is evidence that individuals differ in the strategy they use to navigate through the environment; some use a predominantly verbal-egocentric strategy while others rely more heavily on a spatial-allocentric strategy. In addition, navigational strategy, assessed by a way-finding questionnaire, is predictive of performance on an auditory spatial Stroop task, in which either the semantic or spatial dimension of stimuli must be ignored. To explore the influence of individual differences in navigational style on conflict processing, participants took part in an auditory spatial Stroop task while the electroencephalogram (EEG) was recorded. Whereas behavioral performance only showed a main effect of congruency, we observed the predicted three-way interaction between congruency, task type and navigational style with respect to our physiological measure of Stroop conflict. Specifically, congruency-dependent modulation of the Ninc was observed only when participants performed their non-dominant task (e.g., verbal navigators attempting to ignore semantic information). These results confirm that the Ninc reliably indexes auditory Stroop conflict and extend previous results by demonstrating that the Ninc is predictably modulated by individual differences in cognitive style.

Recent work suggests that biological motion processing can begin within ~110 ms of stimulus onset, as indexed by the P1 component of the event-related potential (ERP). Here, we investigated whether modulation of the P1 component reflects configural processing alone, rather than the processing of both configuration and motion cues. A three-stimulus oddball task was employed to evaluate bottom-up processing of biological motion. Intact point-light walkers (PLWs) or scrambled PLWs served as distractor stimuli, whereas point-light displays of tool motion served as standard and target stimuli. In a second experiment, the same design was used, but the dynamic stimuli were replaced with static point-light displays. The first experiment revealed that dynamic PLWs elicited a larger P1 as compared to scrambled PLWs. A similar P1 increase was also observed for static PLWs in the second experiment, indicating that these stimuli were more salient than static, scrambled PLWs. These findings suggest that the visual system can rapidly extract global form information from static PLWs and that the observed P1 effect for dynamic PLWs is not dependent on the presence of motion cues. Finally, we found that the N1 component was sensitive to dynamic, but not static, PLWs, suggesting that this component reflects the processing of both form and motion information. The sensitivity of P1 to static PLWs has implications for dynamic form models of biological motion processing that posit temporal integration of configural cues present in individual frames of PLW animations.

The development of a microcomputer based finite element program featuring phase change (melting and freezing) simulation and facilities is outlined. A closed form Galerkin finite element method derived from a delta function formulation of the latent heat discontinuity in the heat capacity versus temperature function is used within phase change elements of the solution domain. Storage reduction data structures are implemented and compared on the basis of overall program execution time. Analytical solutions for melting and freezing are used to vertify program accuracy and to explore other simulation parameters such as time step size, mesh density and start-up technique. Several ''life like'' phase change simulations are compared to the results obtained from other numerical models.