Trajectories of frontal brain activity and socio-emotional development in children.

Asymmetric frontal brain activity is thought to reflect individual differences in approach- and avoidance-oriented motivation and emotional experience. Using a prospective longitudinal design, the authors investigated whether trajectories of frontal electroencephalogram (EEG) asymmetry in children (Mage = 6.39 years at enrollment) predicted subjective, behavioral, and autonomic indices of socioemotional processes. Resting frontal EEG activity was measured across four separate repeated assessments spanning approximately 2 years. Children's EEG asymmetry across assessments was best characterized by two trajectories: a stable right frontal asymmetry class (48.65%), and a stable left frontal asymmetry class (51.35%). At visit 4, children in the stable right frontal asymmetry displayed more avoidance-related tendencies and children in the stable left frontal asymmetry class exhibited more approach-related tendencies across social, emotional, and autonomic measures. These findings suggest that developmental patterns of resting frontal brain activity across the early school years may underlie approach- and avoidance-related motivation and predict socio-emotional processes in some children.

Distinguishing shyness and sociability in children: An event-related potential study.

Shyness and sociability are independent personality dimensions, each with distinct behavioral and psychophysiological correlates that are conserved across development, culture, and phylogeny. However, relatively little is known regarding how shyness and sociability are instantiated in the brain, particularly during childhood and during the processing of nonsocial stimuli. Using a three-stimulus auditory oddball task, we examined whether variations in shyness and sociability were related to the N200 and P300 event-related potential (ERP) brain responses to processing task-relevant, novel, and standard auditory tones in 53 typically developing 10-year-old children. ERP amplitudes were measured at four midline scalp sites: Fz, FCz, Cz, and Pz. We found that increases in shyness were correlated with increases in target P300 amplitudes across all four head sites, increases in standard P300 amplitudes, and decreases in target P300 latencies in anterior sites. No relations were found for sociability and P300 responses. We also found that P300 amplitude in the frontal region to standard tones mediated the relation between conflicted shyness (i.e., high shyness and high sociability) and emotional instability. These results suggest that shyness and sociability are distinguishable on neurocognitive measures and that these neurocognitive measures may be putative mechanisms in understanding risk for emotional instability and a broad range of dysregulated behavioral problems observed in individuals characterized by conflicted shyness.

Adolescent anxiety and aggression can be differentially predicted by electrocortical phase reset variables.

Increasing evidence supports the notion that both internalizing (e.g., anxiety) and externalizing (e.g., aggression) behavioral dysregulation are associated with abnormal communication between brain regions. Electroencephalographic (EEG) signals across two electrode sites are said to be coherent with one another when they show consistent phase relations. However, periods of desynchrony with shifting of phase relations are a necessary aspect of information processing. The components of EEG phase reset ('locking' when two regions remain in synchrony, and 'shifting' when the two regions desynchronize momentarily) show dramatic changes across development. We collected resting EEG data from typically developing 12 to 15-year-olds and calculated phase shift and lock values in the alpha frequency band across 14 pairs of electrodes varying in inter-electrode distance. A composite measure of participants' aggression levels was positively associated with phase shifting, particularly in the low alpha frequency range, most strongly over the left hemisphere, consistent with the relatively greater left-prefrontal activity reported in aggressive adults. A composite measure of anxiety levels was positively associated with alpha phase locking at sites over both hemispheres, consistent with changes in connectivity reported during anxious thinking in adults. Associations with anxiety could not be explained by traditional EEG coherence measures and suggest that phase shifting and locking might provide an important non-invasive associate of clinically problematic behavior.

The impact of sound in modern multiline video slot machine play.

Slot machine wins and losses have distinctive, measurable, physiological effects on players. The contributing factors to these effects remain under-explored. We believe that sound is one of these key contributing factors. Sound plays an important role in reinforcement, and thus on arousal level and stress response of players. It is the use of sound for positive reinforcement in particular that we believe influences the player. In the current study, we investigate the role that sound plays in psychophysical responses to slot machine play. A total of 96 gamblers played a slot machine simulator with and without sound being paired with reinforcement. Skin conductance responses and heart rate, as well as subjective judgments about the gambling experience were examined. The results showed that the sound influenced the arousal of participants both psychophysically and psychologically. The sound also influenced players' preferences, with the majority of players preferring to play slot machines that were accompanied by winning sounds. The sounds also caused players to significantly overestimate the number of times they won while playing the slot machine.

Perinatal nicotine exposure relates to stimulus-locked event-related potentials in early adolescence during an emotional go/no-go task.

Nicotine exposure is associated with negative consequences on the developing brain, both in utero and after birth. We investigated the relationship between perinatal nicotine exposure and electroencephalographic brain activity recorded during an emotional faces Go/No-Go task among adolescents. Seventy-one adolescents aged 12-15 years completed a Go/No-Go task using fearful and happy faces. Parents completed questionnaire measures of their child's temperament and self-regulation and retrospectively reported on nicotine exposure during the perinatal period. Perinatally exposed children (n = 20) showed increased and prolonged frontal event-related potential (ERP) differentiation in stimulus-locked analyses; that is, greater emotion and condition differentiation in comparison with their non-exposed peers (n = 51). However, non-exposed children showed greater late emotion differentiation recorded over posterior sites. Response-locked ERP differences were not found. ERP effects were not related to temperamental, self-regulatory, or parental education and income-related factors. This study is the first to demonstrate a relationship between perinatal nicotine exposure and ERPs in an emotional Go/No-Go task among adolescents. Findings suggest that while conflict detection remains intact for adolescents with perinatal nicotine exposure, their attentional allocation to behaviourally relevant stimuli may be magnified to beyond optimal levels, particularly when emotion is salient in information processing. Future studies can extend these findings by isolating prenatal nicotine exposure and comparing its effects to isolated postnatal exposure and clarifying the implications of the face and performance processing differences in adolescence.

Corticotropin-releasing hormone receptor type 1 (CRHR1) genetic variation and stress interact to influence reward learning.

Stress is a general risk factor for psychopathology, but the mechanisms underlying this relationship remain largely unknown. Animal studies and limited human research suggest that stress can induce anhedonic behavior. Moreover, emerging data indicate that genetic variation within the corticotropin-releasing hormone type 1 receptor gene (CRHR1) at rs12938031 may promote psychopathology, particularly in the context of stress. Using an intermediate phenotypic neurogenetics approach, we assessed how stress and CRHR1 genetic variation (rs12938031) influence reward learning, an important component of anhedonia. Psychiatrically healthy female participants (n = 75) completed a probabilistic reward learning task during stress and no-stress conditions while 128-channel event-related potentials were recorded. Fifty-six participants were also genotyped across CRHR1. Response bias, an individual's ability to modulate behavior as a function of reward, was the primary behavioral variable of interest. The feedback-related positivity (FRP) in response to reward feedback was used as a neural index of reward learning. Relative to the no-stress condition, acute stress was associated with blunted response bias as well as a smaller and delayed FRP (indicative of disrupted reward learning) and reduced anterior cingulate and orbitofrontal cortex activation to reward. Critically, rs12938031 interacted with stress to influence reward learning: both behaviorally and neurally, A homozygotes showed stress-induced reward learning abnormalities. These findings indicate that acute, uncontrollable stressors reduce participants' ability to modulate behavior as a function of reward, and that such effects are modulated by CRHR1 genotype. Homozygosity for the A allele at rs12938031 may increase risk for psychopathology via stress-induced reward learning deficits.

Changes in EEG cross-frequency coupling during cognitive behavioral therapy for social anxiety disorder.

Coupling between EEG delta and beta oscillations is enhanced among anxious and healthy individuals during anticipatory anxiety. EEG coupling patterns associated with psychotherapy have not yet been quantified in socially anxious individuals. In this study, we used a double baseline, repeated measures design, in which 25 adults with a principal diagnosis of social anxiety disorder completed 12 weekly sessions of standardized group cognitive behavioral therapy and four EEG assessments: two at pretreatment, one at midtreatment, and one at posttreatment. Treatment was associated with reductions in symptom severity across multiple measures and informants, as well as reductions in delta-beta coupling at rest and during speech anticipation. Moreover, the clinical group exhibited greater coupling at pretreatment than did post hoc control participants with low social anxiety. The EEG cross-frequency profiles in the clinical group normalized by the posttreatment assessment. These findings provide evidence of concomitant improvement in neural and behavioral functioning among socially anxious adults undergoing psychotherapy.

Frontal brain oscillatory coupling in children of parents with social phobia: a pilot study.

Spectral coupling between delta and beta oscillations has been related to anxiety. The authors provide preliminary evidence that frontal brain oscillatory coupling discriminates children born to socially phobic versus healthy parents, despite there being no difference in parental perceptions of their children's shyness.

Electrophysiological changes during adolescence: a review.

While psychological research has long shown that adolescence is a period of major cognitive and affective transition, recent neurophysiological research has shown that adolescence is also accompanied by observable maturational changes in the brain, both in terms of structure and neurotransmitter function. Given this situation, we would expect that there should be observable and perhaps major changes in electrocortical activity and responses. In this review, we discuss developmental reductions in EEG power and alterations in the dominant band of EEG oscillation frequency, moderated by developmental factors such as growth-related changes in grey and white matter, and in the developmental history of cognitive and sociocultural stressors. Similarly, we summarize alterations in event-related potential components reflecting stimulus processing, response monitoring, and response anticipation. We review the literature on such changes in EEG and event-related potentials during the adolescent period and summarize some of the new developments in the field as well as interpretative difficulties.

Single dose of a dopamine agonist impairs reinforcement learning in humans: evidence from event-related potentials and computational modeling of striatal-cortical function.

Animal findings have highlighted the modulatory role of phasic dopamine (DA) signaling in incentive learning, particularly in the acquisition of reward-related behavior. In humans, these processes remain largely unknown. In a recent study, we demonstrated that a single low dose of a D2/D3 agonist (pramipexole)-assumed to activate DA autoreceptors and thus reduce phasic DA bursts-impaired reward learning in healthy subjects performing a probabilistic reward task. The purpose of this study was to extend these behavioral findings using event-related potentials and computational modeling. Compared with the placebo group, participants receiving pramipexole showed increased feedback-related negativity to probabilistic rewards and decreased activation in dorsal anterior cingulate regions previously implicated in integrating reinforcement history over time. Additionally, findings of blunted reward learning in participants receiving pramipexole were simulated by reduced presynaptic DA signaling in response to reward in a neural network model of striatal-cortical function. These preliminary findings offer important insights on the role of phasic DA signals on reinforcement learning in humans and provide initial evidence regarding the spatiotemporal dynamics of brain mechanisms underlying these processes.

Frontal Brain Asymmetry and the Trajectory of Shyness Across the Early School Years.

Although resting right frontal electroencephalogram (EEG) asymmetry has been linked to avoidance and withdrawal-related behaviors such as shyness in previous cross-sectional studies, relatively little research has examined the influence of frontal brain electrical activity on the development of shyness in children using a prospective, longitudinal study design. Here, we tested whether resting frontal EEG asymmetry predicted the trajectory of children's shyness across five assessments. Children were enrolled in the study during the summer prior to grade 1 (N = 37; Mage = 6.39 years, S.D. = 0.15 years), at which time resting frontal EEG activity and maternal report of children's shyness were collected. Mothers then reported on their child's shyness over another four follow-up assessments, spanning 2 years (winter of grade 1, summer prior to grade 2 entry, winter of grade 2, and summer prior to grade 3). Growth curve analysis revealed that children displaying greater relative right frontal EEG activity had lower levels of shyness relative to children exhibiting greater relative left frontal EEG activity at study enrollment (i.e., age 6), but displayed statistically significant linear increases in shyness across time, with the highest levels of shyness by the summer prior to grade 3 (i.e., age 8). There was, however, no relation between left frontal EEG asymmetry and change in shyness across time. These preliminary findings suggest that right frontal EEG asymmetry may reflect a biological diathesis for the growth of shyness during the early school years.

Individual differences in reinforcement learning: behavioral, electrophysiological, and neuroimaging correlates.

During reinforcement learning, phasic modulations of activity in midbrain dopamine neurons are conveyed to the dorsal anterior cingulate cortex (dACC) and basal ganglia (BG) and serve to guide adaptive responding. While the animal literature supports a role for the dACC in integrating reward history over time, most human electrophysiological studies of dACC function have focused on responses to single positive and negative outcomes. The present electrophysiological study investigated the role of the dACC in probabilistic reward learning in healthy subjects using a task that required integration of reinforcement history over time. We recorded the feedback-related negativity (FRN) to reward feedback in subjects who developed a response bias toward a more frequently rewarded ("rich") stimulus ("learners") versus subjects who did not ("non-learners"). Compared to non-learners, learners showed more positive (i.e., smaller) FRNs and greater dACC activation upon receiving reward for correct identification of the rich stimulus. In addition, dACC activation and a bias to select the rich stimulus were positively correlated. The same participants also completed a monetary incentive delay (MID) task administered during functional magnetic resonance imaging. Compared to non-learners, learners displayed stronger BG responses to reward in the MID task. These findings raise the possibility that learners in the probabilistic reinforcement task were characterized by stronger dACC and BG responses to rewarding outcomes. Furthermore, these results highlight the importance of the dACC to probabilistic reward learning in humans.

Electrophysiological correlates of spatial orienting towards angry faces: a source localization study.

The goal of this study was to examine behavioral and electrophysiological correlates of involuntary orienting toward rapidly presented angry faces in non-anxious, healthy adults using a dot-probe task in conjunction with high-density event-related potentials and a distributed source localization technique. Consistent with previous studies, participants showed hypervigilance toward angry faces, as indexed by facilitated response time for validly cued probes following angry faces and an enhanced P1 component. An opposite pattern was found for happy faces suggesting that attention was directed toward the relatively more threatening stimuli within the visual field (neutral faces). Source localization of the P1 effect for angry faces indicated increased activity within the anterior cingulate cortex, possibly reflecting conflict experienced during invalidly cued trials. No modulation of the early C1 component was found for affect or spatial attention. Furthermore, the face-sensitive N170 was not modulated by emotional expression. Results suggest that the earliest modulation of spatial attention by face stimuli is manifested in the P1 component, and provide insights about mechanisms underlying attentional orienting toward cues of threat and social disapproval.

Single dose of a dopamine agonist impairs reinforcement learning in humans: behavioral evidence from a laboratory-based measure of reward responsiveness.

RATIONALE: The dopaminergic system, particularly D2-like dopamine receptors, has been strongly implicated in reward processing. Animal studies have emphasized the role of phasic dopamine (DA) signaling in reward-related learning, but these processes remain largely unexplored in humans. OBJECTIVES: To evaluate the effect of a single, low dose of a D2/D3 agonist--pramipexole--on reinforcement learning in healthy adults. Based on prior evidence indicating that low doses of DA agonists decrease phasic DA release through autoreceptor stimulation, we hypothesized that 0.5 mg of pramipexole would impair reward learning due to presynaptic mechanisms. MATERIALS AND METHODS: Using a double-blind design, a single 0.5-mg dose of pramipexole or placebo was administered to 32 healthy volunteers, who performed a probabilistic reward task involving a differential reinforcement schedule as well as various control tasks. RESULTS: As hypothesized, response bias toward the more frequently rewarded stimulus was impaired in the pramipexole group, even after adjusting for transient adverse effects. In addition, the pramipexole group showed reaction time and motor speed slowing and increased negative affect; however, when adverse physical side effects were considered, group differences in motor speed and negative affect disappeared. CONCLUSIONS: These findings show that a single low dose of pramipexole impaired the acquisition of reward-related behavior in healthy participants, and they are consistent with prior evidence suggesting that phasic DA signaling is required to reinforce actions leading to reward. The potential implications of the present findings to psychiatric conditions, including depression and impulse control disorders related to addiction, are discussed.

Enhanced negative feedback responses in remitted depression.

Major depressive disorder (MDD) is characterized by hypersensitivity to negative feedback that might involve frontocingulate dysfunction. MDD patients exhibit enhanced electrophysiological responses to negative internal (errors) and external (feedback) cues. Whether this dysfunction extends to remitted depressed (RD) individuals with a history of MDD is currently unknown. To address this issue, we examined the feedback-related negativity in RD and control participants using a probabilistic punishment learning task. Despite equivalent behavioral performance, RD participants showed larger feedback-related negativities to negative feedback relative to controls; group differences remained after accounting for residual anxiety and depressive symptoms. The present findings suggest that abnormal responses to negative feedback extend to samples at increased risk for depressive episodes in the absence of current symptoms.

Frontal EEG asymmetry and sensation seeking in young adults.

Sensation seeking has been characterized as a desire to seek novel, intense sensations, and the willingness to take risks in pursuing them. In two separate studies of young adults, we examined the relation between measures of sensation seeking and the pattern of resting frontal EEG asymmetry, thought to reflect a biological predisposition to approach new experiences. As predicted, high sensation seeking was related to a greater relative left frontal activity at rest in both studies, which may be specific to men. How greater relative left frontal cortical activity at rest is related to a tendency to engage in sensation-seeking and risky behaviors is discussed.

Developmental differences in error-related ERPs in middle- to late-adolescent males.

Although there are some studies documenting structural brain changes during late adolescence, there are few showing functional brain changes over this period in humans. Of special interest would be functional changes in the medial frontal cortex that reflect response monitoring. In order to examine such age-related differences, the authors analyzed event-related potentials following errors in a visual flanker task and a go/no-go task in adolescent males, 15-16 and 18-20 years old. Response times and accuracy were comparable between groups on each task, but the younger group made more go/no-go errors, suggesting this task was more difficult. Error-related negativity, thought to be generated in the anterior cingulate cortex (ACC), had greater amplitude for the older adolescents on both tasks; thus the increased errors are not simply due to performance level differences. Results from this study suggest that the ACC, which supports response monitoring, is late to mature due to age-related structural or neurochemical changes.

Adverse childhood experiences are associated with self-regulation and the magnitude of the error-related negativity difference.

Trauma and stress, like that which occurs as a result of adverse childhood experiences (ACEs), can change brain structure and function, especially in medial prefrontal and hippocampal areas, and can impact self-regulatory skill. The error-related negativity (ERN) is a medial frontal negative event-related potential (ERP) component that is more negative when a participant makes an erroneous versus correct response. We investigated the association of ACEs to adolescents' ERN and self-regulation. Forty-three 12-15 year olds performed a flanker task while EEG data were recorded. We found an interaction between trial type (correct vs incorrect) and group (low, medium and high trauma groups) on the ERN. The high-trauma group showed a larger Error-Correct difference than the low- and medium-trauma groups. This appeared as trend correlations between overall trauma exposure as a continuous variable and ERN-related variables. Trauma exposure was associated with reduced self-regulatory capacity, and accounting for self-regulation decreased the associations between trauma and the ERN, suggestive of a protective effect for self-regulation.

Retest reliability in adolescents of a computerized neuropsychological battery used to assess recovery from concussion.

We examined in a group of 15-year-old adolescents the retest reliability over one week of 7 subscales of the Automated Neuropsychological Metrics (ANAM), a computerized battery based on standard neuropsychological test measures that is one of several such batteries available to assess concussion effects. Since the principle behind these computerized batteries is to assess athletes before injury and after injury to determine the level of deficit and whether the individual is safe to return to play, it is critical that such batteries have excellent retest reliability. Retest reliability of the ANAM was good, especially for the aggregate of throughput scores, reaching 0.87, but lower for individual subtests, especially for those measuring only speed of processing. Thus, the ANAM aggregated score appears to have robust reliability for cognitive measures involving memory and attention in 15-year-olds. Limitations related to assessing return-to-baseline after concussion in adolescents are discussed.

Error-related electrocortical responses are enhanced in children with obsessive-compulsive behaviors.

The error-related negativity (ERN or Ne) and positivity (Pe) are event-related potential components elicited during simple discrimination tasks after an error response. The ERN and Pe have a fronto-central scalp distribution and may be an indirect measure of anterior cingulate (AC) activity as it relates to performance monitoring. Brain imaging studies suggest that obsessive-compulsive disorder (OCD) is associated with exaggerated activity of the AC while electrophysiological studies have found an association between OCD and pronounced ERNs in adults. The present study explored the relation between obsessive-compulsive behaviors, the ERN, and the Pe in a sample of nonclinical 10-year-old children. It was found that more parent-reported obsessive-compulsive behaviors were associated with larger ERN and Pe components in the children. Results suggest unique contributions of the ERN and Pe in predicting obsessive-compulsive behaviors.