Prefrontal transcranial direct current stimulation over the right prefrontal cortex reduces proactive and reactive control performance towards emotional material in healthy individuals

The prefrontal cortex plays a crucial role in cognitive processes, both during anticipatory and reactive modes of cognitive control. Transcranial Direct Current Stimulation (tDCS) can modulate these cognitive resources. However, there is a lack of research exploring the impact of tDCS on emotional material processing in the prefrontal cortex, particularly in regard to proactive and reactive modes of cognitive control. In this study, 35 healthy volunteers underwent both real and sham tDCS applied to the right prefrontal cortex in a counterbalanced order, and then completed the Cued Emotion Control Task (CECT). Pupil dilation, a measure of cognitive resource allocation, and behavioral outcomes, such as reaction time and accuracy, were collected. The results indicate that, as compared to sham stimulation, active right-sided tDCS reduced performance and resource allocation in both proactive and reactive modes of cognitive control. These findings highlight the importance of further research on the effects of tDCS applied to the right prefrontal cortex on cognitive engagement, particularly for clinical trials utilizing the present electrode montage in combination with cognitive interventions. (AU)

Uncovering the underlying factors of ERP changes in the cyberball paradigm: A systematic review investigating the impact of ostracism and paradigm characteristics.

The Cyberball is the most commonly employed paradigm for the investigation of the effects of social exclusion, also called ostracism. The analysis of event-related potentials (ERPs), short-term stimulus-induced fluctuations in the EEG signal, has been employed for the identification of time-sensitive neural responses to ostracism-related information. Changes in ERPs during the Cyberball are normally attributed to the effect of ostracism, but it has been argued that characteristics of the paradigm, not ostracism, are the driving force for these changes. To elucidate the origin of the ERP changes in the Cyberball, we systematically reviewed the Cyberball-ERP literature of healthy, adult populations, and evaluated whether the social context of ostracism or characteristics of the paradigm are better suited for the explanation of the found results. Our results show that for many components no clear origin can be identified, but that expectancy violations, not ostracism, best explains the results of the P3 complex. Future research should therefore also employ other paradigms for the research into the effects of ostracism on ERPs.

Cognitive behavioral based group psychotherapy focusing on repetitive negative thinking: Decreased uncontrollability of rumination is related to brain perfusion increases in the left dorsolateral prefrontal cortex.

Repetitive negative thinking (RNT) is a core process underlying various psychiatric disorders. 'Uncontrollability of rumination (UOR)' is one the most maladaptive factors of rumination, but little is known on how cognitive behavioral focused RNT psychotherapy may alter brain activity. In a subsample of 47 patients suffering from RNT who also underwent brain imaging (registered RCT trial NCT01983033), we evaluated the effect of cognitive behavioral based group psychotherapy (CBGP) (n = 25) as compared to a delayed treatment control group (DTCG) (n = 22) on frontolimbic brain perfusion with a focus on UOR. This RNT construct was measured using the subscale 'uncontrollability' of the Dutch version of the Rumination on Sadness Scale (LARSS-U). Brain perfusion was assessed with arterial spin labeling (ASL)-fMRI. LARSS-U scale scores significantly decreased in the CBGP cohort whereas no significant changes emerged in the DTCG group. Compared to the DTCG, this decrease on UOR in the CBGP group was related to significant perfusion increases in the left (dorsolateral) prefrontal cortex, part of the executive network. Besides the fact that CBGP significantly reduced RNT, this attenuation of uncontrollable ruminative thoughts was related to brain perfusion increases areas documented to be involved in the top down control of adaptive emotion regulation and the inhibition of ruminative processes.

Resilience at information processing level in older adults: maintained attention for happy faces when positive mood is low

Even though ageing is associated with declining cognitive capabilities, research has demonstrated an agerelated improvement in affective well-being. This improvement can be related to increased resilience, developing as changes in emotion regulation at information-processing level. During negative mood, emotion regulation becomes a priority as demonstrated by an increased preference for positive over negative information in older adults. However, the effect of a positive mood on older adult’s attentional preferences has not been established yet. To investigate this, 37 older adults were randomly assigned to a relaxation or a control condition (music). Mood state was assessed before and after the manipulation. Attentional bias was measured by an exogenous cueing task, in which the location of the target was correctly or incorrectly cued by happy, sad or neutral facial pictures. Both groups showed a decrease in negative mood (p < .001, 95% CI [2.73, 5.97], d = .82) without changes in positive mood. The relaxation group showed a significantly bigger increase in feeling relaxed (p = .017, η2 p = .15). No significant group differences were found for attentional bias. However, over the whole group, less positive mood after the manipulation was associated with more maintained attention for positive information (r = -.49, p < .01). These results indicate that older adults deploy emotion regulation strategies in attention during low positive mood. Flexible attentional processing of emotional information might serve as a resilience factor to maintain well-being during later stages of life (AU)

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Effects of positive mood on attentional breadth for emotional stimuli.

Although earlier studies have related positive emotions to attentional broadening, recent findings point out the complexity of this relation and show that these broadening effects interact with factors such as characteristics of the information that is presented. Besides stimuli characteristics, individual characteristics such as the presence of depressive symptoms could also influence the broadening effects as depressive symptoms have previously been related to a more narrow attentional scope. Therefore, the aim of this study was to further investigate the attentional broadening effects of positive emotions, testing whether this is influenced by the emotional valence of the information presented and secondly, how the presence of depressive symptoms might interact with this relationship. We used a performance-based measure to assess fluctuations in attentional broadening for positive, neutral, and negative stimuli. We assessed the presence and severity of depressive symptoms in an unselected study sample and tested whether these symptoms moderate the relationship between induced positive mood and attentional breadth for emotional information. Results showed no direct relation between positive mood and attentional breadth, regardless of the emotional valence of the stimuli. However, the presence of depressive symptoms moderated this relationship in such a way that among low levels of depressive symptoms, positive mood was related to attentional broadening specifically when positive information was presented, while at high levels of depressive symptoms this relation was reversed. The current findings suggest that both stimuli characteristics, individual characteristics and their interplay should be taken into account when investigating the broadening effects of positive emotions.