Evidence against combined effects of stress and brain stimulation on working memory

The effect of stress on working memory has been traced back to a modulation of the prefrontal cortex (PFC). We investigated the effects of neuromodulation of the left dorsolateral prefrontal cortex (lDLPFC) after exposure to psychosocial stress through the Socially Evaluated Cold Pressure Test (SECPT). The hypothesis was that neuromodulation interacts with the stress intervention, to either boost performance even under stressed conditions or compensate negative stress effects. Fifty-nine participants were randomly divided into two groups. One group received active, anodal, offline transcranial direct current stimulation (tDCS) over the lDLPFC while the other group received sham stimulation. Participants performed a lexical n-back task, before and after the SECPT and tDCS intervention. The first n-back task was used as a baseline measurement and the second n-back task was performed during recovery from stress when cortisol levels are at their peak, but still under the influence of tDCS aftereffects. Additionally, after the psychosocial stress phase participants were post-hoc divided into cortisol responders and nonresponders. Results showed that generally stress increased lexical n-back task performance as indicated by faster correct reaction times and higher accuracy but that this was not modulated by tDCS. Crucially, using Bayes analysis we obtained evidence against the influence of anodal tDCS on stressed individual's working memory performance

Transcranial direct current stimulation over the left anterior temporal lobe during memory retrieval differentially affects true and false recognition in the DRM task

Transcranial direct current stimulation (tDCS) is a form of non-invasive brain stimulation that has been used to modulate human brain activity and cognition. One area which has not yet been extensively explored using tDCS is the generation of false memories. In this study, we combined the Deese-Roediger-McDermott (DRM) task with stimulation of the left anterior temporal lobe (ATL) during retrieval. This area has been shown to be involved in semantic processing in general and retrieval of false memories in the DRM paradigm in particular. During stimulation, 0.7 mA were applied via a 9 cm² electrode over the left ATL, with the 35 cm² return electrode placed over the left deltoid. We contrasted the effects of cathodal, anodal, and sham stimulation, which were applied in the recognition phase of the experiment on a sample of 78 volunteers. Results showed impaired recognition of true memories after both anodal and cathodal stimulation in comparison to sham stimulation, suggesting a reduced signal-to-noise ratio. In addition, the results revealed enhanced false recognition of concept lure items during cathodal stimulation compared to anodal stimulation, indicating a polarity-dependent impact of tDCS on false memories in the DRM task. The pathway by which tDCS modulated false recognition remains unclear: stimulation may have changed the activation of irrelevant lures or affected the weighting and monitoring of lure activations. Nevertheless, these results are a first step towards using brain stimulation to decrease false memories. Practical implications of the findings for real-life settings, for example, in the courtroom, need to be addressed in future work

Treating a 20 mm Hg Gradient Alleviates Myocardial Hypertrophy in Experimental Aortic Coarctation

Background Children with coarctation of the aorta (CoA) can have a hyperdynamic and remodeled left ventricle (LV) from increased afterload. Literature from an experimental model suggests the putative 20 mm Hg blood pressure gradient (BPG) treatment guideline frequently implemented in CoA studies may permit irreversible vascular changes. LV remodeling from pressure overload has been studied, but data are limited following correction and using a clinically representative BPG. Materials and methods Rabbits underwent CoA at 10 weeks to induce a 20 mm Hg BPG using permanent or dissolvable suture thereby replicating untreated and corrected CoA, respectively. Cardiac function was evaluated at 32 weeks by magnetic resonance imaging using a spoiled cine GRE sequence (TR/TE/FA 8/2.9/20), 14 × 14-cm FOV, and 3-mm slice thickness. Images (20 frames/cycle) were acquired in 6-8 short axis views from the apex to the mitral valve annulus. LV volume, ejection fraction (EF), and mass were quantified. Results LV mass was elevated for CoA (5.2 ± 0.55 g) versus control (3.6 ± 0.16 g) and corrected (4.0 ± 0.44 g) rabbits, resulting in increased LV mass/volume ratio for CoA rabbits. A trend toward increased EF and stroke volume was observed but did not reach significance. Elevated EF by volumetric analysis in CoA rabbits was supported by concomitant increases in total aortic flow by phase-contrast magnetic resonance imaging. Conclusions The indices quantified trended toward a persistent hyperdynamic LV despite correction, but differences were not statistically significant versus control rabbits. These findings suggest the current putative 20 mm Hg BPG for treatment may be reasonable from the LV\u27s perspective

Sustainable Production: Recycling of Bacterial Biomass Resulting from a Fermentation Process with Klebsiella planticola

The Gram-negative bacterium Klebsiella planticola represents an interesting host organism for the production of biotechnological products. Microbial processes – especially those of aerobic cultivation – lead to the generation of considerable amounts of biomass, thus lowering the product yield. These are the reasons for studying methods for the recycling of biomass from K. planticola. It will be shown that it is possible to disintegrate the microbial biomass – preferably by means of high pressure homogenization followed by a protease treatment of the resulting slurry of debris – in an efficient way and to recycle at least the soluble part as cultivation medium component. A recycling yield of about 77 % can be achieved. By studying the growth of K. planticola in a cyclic batch cultivation strategy with maximal recycling of the biomass no adverse effects have been observed for a series of more than 9 consecutive cultivation cycles

The (gami)fictional ego-center: Projecting the location of the self into an avatar

A rich body of research suggests that self-associated stimuli are preferentially processed and therefore responses to such stimuli are typically faster and more accurate. In addition, people have an understanding of what they consider their "Self" and where it is located, namely near the head and upper torso-further boosting the processing of self-related stimuli if they are presented near the felt location of the self. We were interested in whether the same mechanism can be found when people transfer their "Self" into a static avatar. We investigated this in two studies with N = 33 and N = 39 young, healthy adults, respectively. Taken together, the results showed that (i) people indeed show enhanced processing for self-avatar-related stimuli and (ii) that self-associations are stronger if the to-be-associated stimuli are closer to the avatar's upper torso-suggesting some kind of a projected location of the self in the avatar. This implies that attention is not equally distributed across the avatar. Beyond a theoretical level, this also has implications for practical use. For example, digital games opting for a non-traditional user interface where information is displayed on or in the direct vicinity of the character should take this effect into account when choosing which information to present where (i.e., present the most crucial piece of information close to the self-center of the avatar)

Effects of single-session transcranial direct current stimulation on reactive response inhibition

Transcranial direct current stimulation (tDCS) is widely used to explore the role of various cortical regions for reactive response inhibition. In recent years, tDCS studies reported polarity-, time- and stimulation-site dependent effects on response inhibition. Given the large parameter space in which study designs, tDCS procedures and task procedures can differ, it is crucial to systematically explore the existing tDCS literature to increase the current understanding of potential modulatory effects and limitations of different approaches. We performed a systematic review on the modulatory effects of tDCS on response inhibition as measured by the Stop-Signal Task. The final dataset shows a large variation in methodology and heterogeneous effects of tDCS on performance. The most consistent result across studies is a performance enhancement due to anodal tDCS over the right prefrontal cortex. Partially sub-optimal choices in study design, methodology and lacking consistency in reporting procedures may impede valid conclusions and obscured the effects of tDCS on response inhibition in some previous studies. Finally, we outline future directions and areas to improve research

Anti-immigrant prejudice and discrimination in Europe

Europe is a continent of immigration, emigration and internal migration. In this chapter, we review recent literature that demonstrates that immigrants to Europe face prejudice, discrimination, and violence. Levels of prejudice, discrimination and violence targeted at immigrants vary between European countries, over time and the particular immigrant group under scrutiny. Classical psychological explanations regarding causes and reasons for rejection are supported in the European context: These include dispositional influences, such as right-wing authoritarianism and social dominance orientation; situational influences, such as high nationalistic identification, intergroup anxiety and threat, lack of contact; and macro-level influences, such as politics and media coverage. Based on the reviewed literature, we propose a model of micro-macro influences on prejudice, discrimination, and violence against immigrants that organizes the existing research and reveals important areas for future research, especially research investigating micro-macro interactions. Looking into the future, we criticize that the continuation of the current walling of Europe against immigrants will reinforce future processes of devaluation and dehumanization

More than skin deep: About the influence of self-relevant avatars on inhibitory control

AbstractOne important aspect of cognitive control is the ability to stop a response in progress and motivational aspects, such as self-relevance, which may be able to influence this ability. We test the influence of self-relevance on stopping specifically if increased self-relevance enhances reactive response inhibition. We measured stopping capabilities using a gamified version of the stop-signal paradigm. Self-relevance was manipulated by allowing participants to customize their game avatar (Experiment 1) or by introducing a premade, self-referential avatar (Experiment 2). Both methods create a motivational pull that has been shown to increase motivation and identification. Each participant completed one block of trials with enhanced self-relevance and one block without enhanced self-relevance, with block order counterbalanced. In both experiments, the manipulation of self-relevance was effective in a majority of participants as indicated by self-report on the Player-Identification-Scale, and the effect was strongest in participants that completed the self-relevance block first. In those participants, the degree of subjectively experienced that self-relevance was associated with improvement in stopping performance over the course of the experiment. These results indicate that increasing the degree to which people identify with a cognitive task may induce them to exert greater, reactive inhibitory control. Consequently, self-relevant avatars may be used when an increase in commitment is desirable such as in therapeutic or training settings

Enhanced esports: Community perspectives on performance enhancers in competitive gaming

This work explores perceptions of performance enhancer usage in esports. Specifically, we explored the perception of: food and food supplements; non-medical use of prescription drugs; drugs with some social acceptance (e.g. alcohol, nicotine, cannabis); drugs with lower social acceptance (e.g., psychedelics, opioids); and non-invasive brain stimulation (e.g. transcranial direct current stimulation). A mixed-methods approach was used to triangulate findings around three data sets, including both prompted and unprompted online forum comments, as well as survey data. The studies evidence that players are willing to use or are already using enhancers to increase their in-game performance, and that players are generally concerned about the use of enhancers in professional esports contexts. Furthermore, the community perceives that a substantial number of e-athletes use enhancers. The core contribution of this work is a comprehensive investigation into perspectives of esports performance enhancement, which highlights the urgent need for further research, as well as regulation by esports leagues

Shocking advantage! Improving digital game performance using non-invasive brain stimulation

As digital gaming has grown from a leisure activity into a competitive endeavor with college scholarships, celebrity, and large prize pools at stake, players search for ways to enhance their performance, including through coaching, training, and employing tools that yield a performance advantage. Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that is presently being explored by esports athletes and competitive gamers. Although shown to modulate cognitive processing in standard laboratory tasks, there is little scientific evidence that tDCS improves performance in digital games, which are visually complex and attentionally demanding environments. We applied tDCS between two sessions of the Stop-Signal Game (SSG; Friehs, Dechant, Vedress, Frings, Mandryk, 2020). The SSG is a custom-built infinite runner that is based on the Stop-Signal Task (SST; Verbruggen et al., 2019). Consequently, the SSG can be used to evaluate response inhibition as measured by Stop-Signal Reaction Time (SSRT), but in an enjoyable 3D game experience. We used anodal, offline tDCS to stimulate the right dorsolateral prefrontal cortex (rDLPFC); a 9 cm² anode was always positioned over the rDLPFC while the 35 cm² cathode was placed over the left deltoid. We hypothesized that anodal tDCS would enhance neural processing (as measured by a decrease in SSRT) and improve performance, while sham stimulation (i.e., the control condition with a faked stimulation) should lead to no significant change. In a sample of N = 45 healthy adults a significant session x tDCS-condition interaction emerged in the expected direction. Subsequent analysis confirmed that the statistically significant decrease in SSRT after anodal tDCS to the rDLPFC was not due to a general change in reaction times. These results provide initial evidence that tDCS can influence performance in digital games