Disruption and rescue of interareal theta phase coupling and adaptive behavior

Rescuing executive functions in people with neurological and neuropsychiatric disorders has been a major goal of psychology and neuroscience for decades. Innovative computer-training regimes for executive functions have made tremendous inroads, yet the positive effects of training have not always translated into improved cognitive functioning and often take many days to emerge. In the present study, we asked whether it was possible to immediately change components of executive function by directly manipulating neural activity using a stimulation technology called high-definition transcranial alternating current stimulation (HD-tACS). Twenty minutes of inphase stimulation over medial frontal cortex (MFC) and right lateral prefrontal cortex (lPFC) synchronized theta (∼6 Hz) rhythms between these regions in a frequency and spatially specific manner and rapidly improved adaptive behavior with effects lasting longer than 40 min. In contrast, antiphase stimulation in the same individuals desynchronized MFC-lPFC theta phase coupling and impaired adaptive behavior. Surprisingly, the exogenously driven impairments in performance could be instantly rescued by reversing the phase angle of alternating current. The results suggest executive functions can be rapidly up- or down-regulated by modulating theta phase coupling of distant frontal cortical areas and can contribute to the development of tools for potentially normalizing executive dysfunction in patient populations.Published versio

Electrophysiological indices of feedback processing

xii, 76 leaves : ill. (chiefly col.) ; 29 cmAll sentient organisms use contextual information to assess the amount of reward associated with a particular behavior. Human beings have arguably evolved the most sophisticated of these mechanisms and are capable of integrating information over a long duration of time to accurately assess the expected outcome of a chosen action. This thesis used electroencephalography (EEG) to measure how the human brain processes rewarding and punishing feedback in a gambling-type game with variable risk and reward. Experiment 1 determined that phase-locked (evoked) and non-phase-locked (induced) electroencephalographic activity share only partially overlapping generators in human mediofrontal cortex. Experiment 2 determined that the magnitude of certain evoked EEG components during reward processing tracked subsequent changes in bets placed in the next round. These results extend the body of literature by assessing the overlap between induced and evoked EEG components and the role of evoked activity in affecting future decision making

Frontal midline theta and N200 amplitude reflect complementary information about expectancy and outcome evaluation

Feedback ERN (fERN) and frontal midline theta have both been proposed to index a dopamine-like reinforcement learning signal in anterior cingulate cortex (ACC). We investigated these proposals by comparing fERN amplitude and theta power with respect to their sensitivities to outcome valence and probability in a previously collected EEG dataset. Bayesian model comparison revealed a dissociation between the two measures, with fERN amplitude mainly sensitive to valence and theta power mainly sensitive to probability. Further, fERN amplitude was highly correlated with the portion of theta power that is consistent in phase across trials (i.e., evoked theta power). These results suggest that although both measures provide valuable information about cognitive function of frontal midline cortex, fERN amplitude is specifically sensitive to dopamine reinforcement learning signals whereas theta power reflects the ACC response to unexpected events

Intra- and inter-brain synchrony oscillations underlying social adjustment

Humans naturally synchronize their behavior with other people. However, although it happens almost automatically, adjusting behavior and conformity to others is a complex phenomenon whose neural mechanisms are still yet to be understood entirely. The present experiment aimed to study the oscillatory synchronization mechanisms underlying automatic dyadic convergence in an EEG hyperscanning experiment. Thirty-six people performed a cooperative decision-making task where dyads had to guess the correct position of a point on a line. A reinforcement learning algorithm was used to model different aspects of the participants’ behavior and their expectations of their peers. Intra- and inter-connectivity among electrode sites were assessed using inter-site phase clustering in three main frequency bands (theta, alpha, beta) using a two-level Bayesian mixed-effects modeling approach. The results showed two oscillatory synchronization dynamics related to attention and executive functions in alpha and reinforcement learning in theta. In addition, inter-brain synchrony was mainly driven by beta oscillations. This study contributes preliminary evidence on the phase-coherence mechanism underlying inter-personal behavioral adjustment

Acute effects of alcohol on feedback processing and outcome evaluation during risky decision-making: an ERP study

Rationale: Although risky decision-making is one of the hallmarks of alcohol use disorders, relatively little is known about the acute psychopharmacological effects of alcohol on decision-making processes. Objective: The present study investigated the acute effects of alcohol on neural mechanisms underlying feedback processing and outcome evaluation during risky decision-making, using event-related brain potentials (ERPs). Methods: ERPs elicited by positive and negative feedback were recorded during performance of a modified version of the Balloon Analogue Risk Task in male participants receiving either a moderate dose of alcohol (0.65 g/kg alcohol; n = 32) or a non-alcoholic placebo beverage (n = 32). Results: Overall, there was no significant difference in the mean number of pumps between the alcohol and the placebo condition. However, when analyzing over time, it was found that the alcohol group made more riskier choices at the beginning of the task than the placebo group. ERPs demonstrated that alcohol consumption did not affect early processing of negative feedback, indexed by the feedback-related negativity. By contrast, alcohol-intoxicated individuals showed significantly reduced P300 amplitudes in response to negative feedback as compared to sober controls, suggesting that more elaborate evaluation to losses was significantly diminished. Conclusions: These results suggest that alcohol consumption does not influence the ability to rapidly evaluate feedback valence, but rather the ability to assign sufficient attention to further process motivationally salient outcomes. Blunted P300 amplitudes may reflect poor integration of feedback across trials, particularly adverse ones. Consequently, alcohol may keep people from effectively predicting the probability of future gains and losses based on their reinforcement history

Age-dependent characteristics of feedback evaluation related to monetary gains and losses

Abstract Monitoring the consequences of actions is of crucial importance in order to optimize behavior to the challenges of the environment. Recently the age-related aspects of this fundamentally important cognitive processing have been brought into the focus of investigation since behavioral monitoring and related control mechanisms are widely known to be affected by aging. Processing of feedback stimuli is a core mechanism for rapid evaluation of the functionally significant aspects of outcome, guiding behavior towards avoidance or approach. The aim of the present study was to analyze the age-related alterations in the most prominent electrophysiological correlates of feedback processing, the feedback-related negativity (FRN) and the P3 event-related potential components, using a two-choice-single-outcome gambling task with two amounts of monetary stakes. In terms of behavioral indices higher proportion of risky choices was observed after loss than after gain events in both groups. In the young the FRN component was found to be an indicator of the goodness of outcome (loss or gain), and the P3 showed a complex picture of feedback evaluation with selective sensitivity to large amount of gain. In contrast, in the elderly group outcome valence had no effect on the amplitude of the FRN, and the P3 was also insensitive of the complex outcome properties. As the ERP-correlates of feedback processing are not as pronounced in the elderly, it is suggested that normal aging is accompanied by an alteration of the neural mechanisms signaling the most salient feedback stimulus properties

Using Measures of Risk Perception to Predict Information Security Behavior: Insights from Electroencephalography (EEG)

Users’ perceptions of risks have important implications for information security because individual users’ actions can compromise entire systems. Therefore, there is a critical need to understand how users perceive and respond to information security risks. Previous research on perceptions of information security risk has chiefly relied on self-reported measures. Although these studies are valuable, risk perceptions are often associated with feelings—such as fear or doubt—that are difficult to measure accurately using survey instruments. Additionally, it is unclear how these self-reported measures map to actual security behavior. This paper contributes to this topic by demonstrating that risk-taking behavior is effectively predicted using electroencephalography (EEG) via event-related potentials (ERPs). Using the Iowa Gambling Task, a widely used technique shown to be correlated with real-world risky behaviors, we show that the differences in neural responses to positive and negative feedback strongly predict users’ information security behavior in a separate laboratory-based computing task. In addition, we compare the predictive validity of EEG measures to that of self-reported measures of information security risk perceptions. Our experiments show that self-reported measures are ineffective in predicting security behaviors under a condition in which information security is not salient. However, we show that, when security concerns become salient, self-reported measures do predict security behavior. Interestingly, EEG measures significantly predict behavior in both salient and non-salient conditions, which indicates that EEG measures are a robust predictor of security behavior

Event-related potentials in relation to risk-taking: a systematic review

Event-related potentials (ERPs) have been used to investigate neural mechanisms underlying risk-related decisions over the last 16 years. We aimed to systematically evaluate associations between risk-taking and ERP components elicited during decisions and following feedback. A total of 79 articles identified from PsychINFO and PubMed databases met the inclusion criteria. Selected articles assessed early ERP components (feedback-related negativity/FRN, error-related negativity/ERN, and medial frontal negativity/MFN) and the mid-latency P3 component, all using gambling paradigms that involved selecting between choices of varying risk (e.g., Iowa Gambling Task, Balloon Analogue Risk Task, and two-choice gambling tasks). The P3 component was consistently enhanced to the selection of risky options and when positive feedback (as compared to negative feedback) was provided. Also consistently, the early negative components were found to be larger following feedback indicating monetary losses as compared to gains. In the majority of studies reviewed here, risk was conceptualized in the context of simple economical decisions in gambling tasks. As such, this narrow concept of risk might not capture the diversity of risky decisions made in other areas of everyday experience, for example, social, health, and recreational risk-related decisions. It therefore remains to be seen whether the risk-sensitivity of the ERP components reviewed here generalizes to other domains of life.Dilushi Chandrakumar, Daniel Feuerriegel, Stefan Bode, Megan Grech and Hannah A. D. Keag