The relationship between frontal alpha asymmetry and behavioral and brain activity indices of reactive inhibitory control.

Reactive inhibitory control plays an important role in phenotype of different diseases/different phases of a disease. One candidate electrophysiological marker of inhibitory control is frontal alpha asymmetry (FAA). FAA reflects the relative difference in contralateral frontal brain activity. However, the relationship between FAA and potential behavioral/brain activity indices of reactive inhibitory control is not yet clear. We assessed the relationship between resting-state FAA and indicators of reactive inhibitory control. Additionally, we investigated the effect of modulation of FAA via transcranial direct current stimulation (tDCS). We implemented a randomized sham-controlled design with 65 healthy humans (Mage = 23.93; SDage = 6.08; 46 female). Before and after 2 mA anodal tDCS of the right frontal site (with the cathode at the contralateral site) for 20 minutes, we collected EEG data and reactive inhibitory performance in neutral and food-reward conditions using the Stop Signal Task (SST). There was no support for the effect of tDCS on FAA or any indices of reactive inhibitory control. Our correlation analysis revealed an association between inhibitory brain activity in the food-reward condition and (pre-tDCS) asymmetry. Higher right relative to left frontal brain activity was correlated with reduced early-onset inhibitory activity and in contrast, linked with higher late-onset inhibitory control in the food-reward condition. Similarly, event-related potential analyses showed reduced early-onset and enhanced late-onset inhibitory brain activity over time, particularly in the food-reward condition. These results suggest that there can be a dissociation regarding the lateralization of frontal brain activity and early and late onset inhibitory brain activity.

Mindfulness and inhibitory control: Insights from the stop signal task with neutral and reward-associated stimuli.

Mindfulness has been linked to enhanced inhibitory control, yet the dynamics of this relationship, especially in reward situations, are not well understood. Our cross-sectional study aimed to explore the relationship between trait mindfulness and a performance measure of inhibitory control as a function of reward context operationalized by stimuli characteristics, and temporal inhibitory demands. Thirty-six individuals aged 19 to 41 filled out the Mindful Attention Awareness Scale (MAAS) and performed a stop signal task (SST), that included both neutral (stone images) and reward-related (money images) stimuli. The SST encompassed four conditions: neutral go/neutral stop, neutral go/reward stop, reward go/neutral stop, and reward go/reward stop, requiring participants to suppress reactions either during or after encountering reward-related stimuli. The relevant index of inhibitory control is the stop signal reaction time (SSRT), a performance measure of inhibitory control. Our findings showed no notable variation in the relationship between the MAAS score and SSRT across the different conditions. However, there was an overall significant effect of MAAS score on SSRT, irrespective of condition. Results may reflect the benefit of mindfulness on inhibitory control after generalized reward exposure.

Corrigendum: Exposure to depression memes on social media increases depressive mood and it is moderated by self-regulation: Evidence from self-report and resting EEG assessments.

[This corrects the article DOI: 10.3389/fpsyg.2022.880065.].

How salience enhances inhibitory control: An analysis of electro-cortical mechanisms.

Stop-signal tasks (SSTs) combined with human electro-cortical recordings (Event-Related Potentials, ERPs) have revealed mechanisms associated with successful stopping (relative to failed), presumably contributing to inhibitory control. The corresponding ERP signatures have been labeled stop N1 (+/- 100-ms latency), stop N2 (200 ms), and stop P3 (160-250 ms), and argued to reflect more sensory-specific (N1) versus more generic (N2, P3) mechanisms. However, stop N1 and stop N2, as well as latencies of stop-P3, appear to be quite inconsistent across studies. The present work addressed the possible influence of stop-signal salience, expecting high salience to induce clear stop N1s but reduced stop N2s, and short-latency stop P3s. Three SST varieties were combined with high-resolution EEG. An imperative visual (go) stimulus was occasionally followed by a subsequent (stop) stimulus that signalled to withhold the just initiated response. Stop-Signal Reaction Times (SSRTs) decreased linearly from visual-low to visual-high-salience to auditory. Auditory Stop N1 was replicated. A C1-like visual evoked potential (latency < 100 ms) was observed only with high salience, but not robustly associated with successful versus failed stops. Using the successful-failed contrast a visual stop-N1 analogue (112-156 ms post-stop-signal) was identified, as was right-frontal stop N2, but neither was sensitive to salience. Stop P3 had shorter latency for high than for low salience, and the extent of the early high-salience stop P3 correlated inversely with SSRT. These results suggest that salience-enhanced inhibitory control as manifest in SSRTs is associated with generic rather than sensory-specific electrocortical mechanisms.

Seeing attractive faces challenges inhibitory control, especially when mindful.

Previous studies have suggested positive effects of mindfulness on inhibitory control (stopping behaviour). However, scarce previous studies suggest the relationship may depend on context. We provide first evidence that inhibitory control is challenged when perceiving attractive faces, especially when being mindful. Specifically, we investigated the relationship between mindfulness and inhibitory control and the moderating role of a social reward context (being exposed to attractive opposite sex faces). Participants (n = 50) between 18-43 years old (M = 25, SD = 5.4) filled out questionnaires assessing standard demographic variables and dispositional mindfulness. Subsequently, they performed a Go/No-go task with a neutral condition and attractive faces condition. Results showed that inhibitory control was challenged in the attractive condition relative to the neutral condition, p = 0.019. Dispositional mindfulness was negatively correlated with inhibitory performance, but only in the attractive faces condition (r = -0.32, p = 0.024). Results did not support a moderating role of gender. Finally, though post-hoc, higher mindfulness was associated with reduced perceived attractiveness of presented faces (r = -0.33, p = 0.019). However, the relationship between mindfulness and reduced inhibitory control could not be explained by mindfulness associated reduced attractiveness. Taken together, results show that mindfulness challenges inhibitory control when perceiving attractive faces. This implies that mindfulness interventions aimed at enhancing inhibitory control, may not render the desired effect in a context of being exposed to attractive faces. Though certainly plausible, it remains an open question whether results generalize to other reward contexts as well.

Exposure to Depression Memes on Social Media Increases Depressive Mood and It Is Moderated by Self-Regulation: Evidence From Self-Report and Resting EEG Assessments.

This study aimed to investigate the effects of depression memes, spread mainly on social media, on depressive mood, and the moderating role of self-regulation based on self-report and electrophysiological (resting EEG frontal alpha asymmetry) assessments. We conducted a semi-online crossover study; first, we collected brain activity data from healthy young adults (n = 32) who were subsequently provided a link to the online experiment. Each participant participated in both the neutral and meme conditions. We also evaluated their level of depressive mood immediately before and after exposure to the stimuli. We further conducted a series of linear mixed effects model analyses and found that depression memes contributed to an increase in depressive symptoms. Specifically, lack of emotional clarity, difficulties in goal-directed behaviors in emotional distress, and impulse control difficulties were linked to greater depressive mood in the case of exposure to depression memes compared with neutral images. However, time interactions were insignificant. These results mainly indicate the centrality of behavioral problems during times of emotional distress caused by depression memes. Lastly, although frontal alpha asymmetry did not predict a change in depressive mood or significantly differ across conditions, lower inhibitory control may result in increased processing of depression memes as negative stimuli. This result is consistent with our self-report results (e.g., impulsivity) as well as other related studies in the literature. However, further research is needed to verify these frontal alpha asymmetry results.

The relationship between reward context and inhibitory control, does it depend on BMI, maladaptive eating, and negative affect?

BACKGROUND: Recent studies suggest that higher Body Mass Index (BMI) is associated with reduced inhibitory control in contexts of palatable food. However, due to limitations of previous studies, it remained the question whether this reduction is specific to food contexts, and whether it generalizes to other contexts of reward, such as money. This main question was addressed in the current study. In addition, we explored the effect of maladaptive eating and stress regarding inhibitory control across the contexts that differed in terms of reward. METHODS: In total, 46 participants between 19 and 50 years old (39% males and 61% females) with an average BMI of 23.5 (SD = 3.9) participated. Participants filled out questionnaires and performed a go/no-go task (indexing inhibitory control) with three conditions (neutral, food, and money condition). RESULTS: Relatively high (above median) BMI was associated with challenged inhibitory control in the food relative to the neutral context, but not in the money relative to neutral context. Explorative analyses suggested that maladaptive eating and stress were associated with reduced inhibitory control in the food context. Only rumination was associated with reduced inhibitory control in the money context. CONCLUSIONS: The effects of BMI, maladaptive eating behavior, and stress on inhibitory control were specific to the food context, and did not generalize to a non-intrinsic reward condition, operationalized with money pictures. Our results imply that (research on) interventions directed at improving inhibitory control in relation to overweight and obesity, should consider food-reward context.

Interaction between emotional context-guided shifting and cognitive shifting: Introduction of a novel task.

Aim: Task shifting is considered as a critical component of cognitive flexibility that underlies the ability to flexibly switch between tasks. It is measured by performance-based tasks, where participants have to select/ignore simple target stimuli such as letters, numbers, or words according to certain rules. However, in everyday life individuals need to manage and shift between more complex, often emotionally charged stimuli. Previous paradigms developed to measure affective flexibility are based on the task where the focus is to shift between emotional and non-emotional stimuli, instead of the flexible shift between emotional valences. In view of this, the aim of the present study was to develop the Emotional Shifting Task, a novel paradigm that is created with the purpose of assessing emotional flexibility abilities by means of a novel valence-specific shifting design. Furthermore, scientific discussion regarding the relationship between cognitive and emotional flexibility abilities, a connection that is rarely addressed in the literature would be addressed. Method: In the present paper, task shifting was assessed by means of the Task Switching Task while the Emotional Shifting Task method evaluated emotional flexibility abilities in an online setting. Results: The results revealed a significant, positive relationship between task shifting and emotional shifting from positive to negative images only. Furthermore, when fast and slow performers on TST were distinguished results showed that fast performers on TST were also faster on EST shift conditions in general, but not on EST non-shift condition. Conclusion: These findings indicate that cognitive and emotional flexibility abilities may be interrelated. Our results seem to indicate a connection between the two shifting abilities. (Neuropsychopharmacol Hung 2021; 23(2): 319-330).

Attentional bias and disengagement as a function of Body Mass Index in conditions that differ in anticipated reward.

BACKGROUND AND AIMS: Previous studies suggest that attentional bias and disengagement may vary as a function of Body Mass Index (BMI), most notably in a palatable food related context. Though this could indeed represent a food context specific effect, it could also represent a general reward related context effect. In addition, though mindfulness and stress have both been reported to affect attention, it is not yet clear whether these moderate the relationship between BMI and attention as a function of reward context. In the current study we addressed these questions. It was hypothesized that BMI would be positively associated with bias in a food context and money context relative to a neutral context. The inverse was expected for disengagement. It was expected that mindfulness would decrease these relationships and for stress the inverse was expected. METHODS: In the current online study, eighty-seven participants (24 males and 63 females; age: M = 30.1, SD = 8.3; BMI: M = 24.2, SD = 4.67), filled out questionnaires and completed a visuospatial cueing task measuring attention and disengagement of attention in a neutral, food-related, and money-related condition. RESULTS: There was no association between BMI and attentional bias. Higher BMI was associated with faster responses to money pictures presented opposite to a cued location as compared to money pictures that did not follow a predictive cue. Our results do not support a clear moderating role of mindfulness and stress. DISCUSSION AND CONCLUSION: Our results imply faster processing and associated quicker responding to unanticipated reward-related stimuli in individuals with overweight or obesity.

The Effects of ß-Adrenergic Blockade on the Degrading Effects of Eye Movements on Negative Autobiographical Memories.

BACKGROUND: Eye movement desensitization and reprocessing (EMDR) is an effective treatment for posttraumatic stress disorder. During EMDR, patients make horizontal eye movements (EMs) while simultaneously recalling a traumatic memory, which renders the memory less vivid and emotional when it is later recalled again. Recalling highly emotional autobiographical memories enhances noradrenergic neurotransmission. Noradrenaline (NA) strengthens memory (re)consolidation. However, memories become less vivid after recall+EMs. Therefore, NA might either play no significant role or serve to strengthen memories that are degraded by EMs. The present study was designed to test the latter hypothesis. We predicted that blocking NA would abolish the memory degrading effects of EMs. METHODS: Fifty-six healthy participants selected three negative autobiographical memories. One was then recalled while making EMs, one was recalled without EMs, and one was not recalled. Vividness and emotionality of the memories as well as heart rate and skin conductance level during memory retrieval were measured before, directly after, and 24 hours after the EM task. Before the task, participants received a placebo or the noradrenergic ß-receptor blocker propranolol (40 mg). RESULTS: There were no effects of EMs on memory emotionality or psychophysiological measures in the propranolol and placebo groups. However, in the placebo group, but not in the propranolol group, memory vividness significantly decreased from pretest to posttest and follow-up after recall+EMs relative to the control conditions. CONCLUSIONS: Blocking NA abolished the effects of EMs on the vividness of emotional memories, indicating that NA is crucial for EMDR effectiveness and possibly strengthens the reconsolidation of the degraded memory.

Haloperidol 2 mg impairs inhibition but not visuospatial attention.

RATIONALE: The dopaminergic system has been implicated in visuospatial attention and inhibition, but the exact role has yet to be elucidated. Scarce literature suggests that attenuation of dopaminergic neurotransmission negatively affects attentional focusing and inhibition. To the best of our knowledge, this is the first study that evaluated the effect of dopaminergic antagonism on stopping performance. METHODS: Dopaminergic neurotransmission was attenuated in 28 healthy male participants by using 2 mg haloperidol. A repeated-measures placebo-controlled crossover design was implemented, and performance indices of attention and inhibition were assessed in the visual spatial cueing task (VSC) and stop signal task (SST). Additionally, the effect of haloperidol on motoric parameters was assessed. It was expected that haloperidol as contrasted to placebo would result in a reduction of the "validity effect," the benefit of valid cueing as opposed to invalid cueing of a target in terms of reaction time. Furthermore, an increase in stop signal reaction time (SSRT) in the SST was expected. RESULTS AND CONCLUSION: Results partially confirmed the hypothesis. Haloperidol negatively affected inhibitory motor control in the SST as indexed by SSRT, but there were no indications that haloperidol affected bias or disengagement in the VSC task as indicated by a lack of an effect on RTs. Pertaining to secondary parameters, motor activity increased significantly under haloperidol. Haloperidol negatively affected reaction time variability and errors in both tasks, as well as omissions in the SST, indicating a decreased sustained attention, an increase in premature responses, and an increase in lapses of attention, respectively.

The effect of attenuating noradrenergic neurotransmission by clonidine on brain activity measures of visuospatial attention.

OBJECTIVE: In the current study, we investigated the role of noradrenaline in directing (bias) and disengagement of visuospatial attention. METHODS: We assessed the effect of clonidine on event-related brain potential (ERP) reflections of bias and disengagement in a double-blind placebo-controlled crossover design. An initial dose of 200-µg clonidine was replaced by 100 µg because of marked side effects. Twenty-one healthy male participants performed the visual-spatial cueing task while an electroencephalogram (EEG) was recorded. The behavioral output is the validity effect (benefit of cueing in terms of reaction time to targets). ERP indices for bias were the cue-related early directing attention negativity and late directing attention positivity, and the target-elicited P1 and N1 modulations by validity ('validity-effect'). The ERP index for disengagement was the target-elicited 'late positive deflection' modulation by validity. Behavioral analyses were performed on 16 participants, electrophysiological analyses on a subset (n=9). RESULTS: Clonidine attenuated the N1 effect, albeit in a subsample. Neither cue-elicited ERPs nor the behavioral validity effect were affected. Clonidine-induced blood pressure reduction was correlated with the reduction of the late positive deflection effect under clonidine. CONCLUSION: Clonidine attenuated the result of bias in a subsample and may have a modulating effect on disengagement.

The effect of noradrenergic attenuation by clonidine on inhibition in the stop signal task.

Understanding the neuropharmacology of inhibition is of importance to fuel optimal treatment for disorders such as Attention Deficit/Hyperactivity Disorder. The aim of the present study was to assess the effect of noradrenergic antagonism by clonidine on behavioral-performance and brain-activity indices of inhibition. A placebo-controlled, double-blind, randomized, crossover design was implemented. Male (N=21) participants performed in a visual stop signal task while EEG was recorded under clonidine in one session and under placebo in another. We expected that 100 µg clonidine would have a negative effect on EEG indices of inhibition, the Stop N2 and Stop P3. Furthermore, we expected that clonidine would negatively affect the behavioral measure of inhibition, the stop signal reaction time (SSRT). Behavioral analyses were performed on data of 17 participants, EEG analyses on a subset (N=13). Performance data suggested that clonidine negatively affected attention (response variability, omissions) without affecting inhibition as indexed by SSRT. Electrophysiological data show that clonidine reduced the Stop P3, but not the Stop N2, indicating a partial negative effect on inhibition. Results show that it is unlikely that the Stop P3 reduction was related to the effect of clonidine on lapses of attention and on peripheral cardiovascular functioning. In conclusion, the current dose of clonidine had a negative effect on attention and a partial effect on inhibitory control. This inhibitory effect was restricted to the dorsal region of the prefrontal cortex (presumably the superior frontal gyrus) as opposed to the ventral region of the prefrontal cortex (right inferior frontal gyrus).

The effectiveness of EEG-feedback on attention, impulsivity and EEG: a sham feedback controlled study.

EEG-feedback, also called neurofeedback, is a training procedure aimed at altering brain activity, and is used as a treatment for disorders like Attention Deficit/Hyperactivity Disorder (ADHD). Studies have reported positive effects of neurofeedback on attention and other dependent variables. However, double-blind studies including a sham neurofeedback control group are lacking. The inclusion of such group is crucial to control for unspecific effects. The current work presents a sham-controlled, double-blind evaluation. The hypothesis was that neurofeedback enhances attention and decreases impulsive behavior. Participants (n=27) were students selected on relatively high scores on impulsivity/inattention questionnaires (Barrat Impulsivity Scale and Broadbent CFQ). They were assigned to a neurofeedback treatment or a sham group. (sham)Neurofeedback training was planned for 15 weeks consisting of a total of 30 sessions, each lasting 22 min. Before and after 16 sessions (i.e., interim analyses), qEEG was recorded and impulsivity and inattention was assessed using a stop signal task and reversed continuous performance task and two questionnaires. Results of the interim analyses showed that participants were blind with respect to group inclusion, but no trend towards an effect of neurofeedback on behavioral measures was observed. Therefore in line with ethical guidelines the experiment was ceased. These results implicate a possible lack of effect of neurofeedback when one accounts for non-specific effects. However, the specific form of feedback and application of the sham-controlled double-blind design may have diminished the effect of neurofeedback.