Effects of Executive Functions Training in Primary School Students with Borderline Intellectual Functioning Through a Multi-Method, Multi-Informant Intervention: A Pilot Study.

Objective: Borderline Intellectual Functioning (BIF) impacts cognitive functioning and adaptive behavior. Recent studies have demonstrated the efficacy of Executive Functions trainings to support daily-living skills in several clinical populations. However, although the relationship between Executive Functions and BIF has been studied, few studies have explored the effects of cognitive enhancement training for BIF children. Given the pivotal significance of Executive Functions in learning, orchestrating cognitive processes, and modulating affective and behavioral responses, our study aimed to evaluate the efficacy of cognitive enhancement training targeting Executive Functions in a group of 23 children diagnosed with Borderline Intellectual Functioning devoid of neurodevelopmental impairments. Method: We included a multiple assessment based on several informants (children, teachers, parents, and tutors) and provided individualized cognitive enhancement training focused on Executive Functions through both digital and analog activities. The training was highly customized, structured and monitored at various stages of the process activities. The training was composed of 20 sessions, each lasting 2 hours, held twice a week for each child. Results: The obtained results confirmed the efficacy of cognitive enhancement training in improving Executive Functions, the primary target of the intervention, particularly in attention, verbal fluency, planning, inhibitory control, working memory, and flexibility. Furthermore, improvements were observed by all the informants in other cognitive functions, learning, and adaptive behaviors. Conclusions: Our study contributes to the understanding of BIF, emphasizing the efficacy of neuropsychological enhancement through personalized training for EF.

Neuroprotective Effect of Marrubium vulgare Extract in Scopolamine-Induced Cognitive Impairment in Rats: Behavioral and Biochemical Approaches.

The potential of Marrubium vulgare to alleviate scopolamine (Sco)-induced deficits in spatial working memory has drawn considerable scientific interest. This effect is partly attributed to its potent antioxidant and acetylcholinesterase inhibitory (AChEI) activities. This study examined the effects of M. vulgare extract, standardized to marrubiin content, on recognition memory in healthy and Sco-treated rats. Male Wistar rats (200-250 g) were divided into four groups. The extract was orally administered for 21 days and Sco (2 mg/kg) was intraperitoneally injected for 11 consecutive days. Memory performance was assessed using the novel object recognition test. Levels of acetylcholine (ACh), noradrenaline (NA), serotonin (Sero), and brain-derived neurotrophic factor (BDNF) and the phosphorylation of cAMP response element-binding protein (p-CREB) were evaluated in the cortex and hippocampus via ELISA. BDNF and CREB expression levels were assessed using RT-PCR. The results showed that M. vulgare significantly alleviated Sco-induced memory impairment, preserved cholinergic function in the hippocampus, increased NA levels in the brain, and restored pCREB expression in the cortex following Sco-induced reduction. In healthy rats, the extract upregulated BDNF, pCREB, and Bcl2 expression. Our findings indicate that the neuroprotective effects of M. vulgare may be linked to the modulation of cholinergic function, regulation of NA neurotransmission, and influence on key memory-related molecules.

Cognitive Enhancement, Hyperagency, and Responsibility Explosion.

Hyperagency objections appeal to the risk that cognitive enhancement may negatively impact our well-being by giving us too much control. I charitably formulate and engage with a prominent version of this objection due to  Sandel (2009)-viz., that cognitive enhancement may negatively impact our well-being by creating an "explosion" of responsibilities. I first outline why this worry might look prima facie persuasive, and then I show that it can ultimately be defended against. At the end of the day, if we are to resist cognitive enhancement, it should not be based on a Sandel-style hyperagency argument.

Well-designed manufacturing work improves some cognitive abilities in individuals with cognitive impairments.

Introduction: Employment is recognized as a fundamental human right, which correlates with better physical and mental health. Importantly, well-designed work, which considers the physical, social, and psychological impacts of work, can serve to enhance the cognitive abilities of workers. Although often overlooked, work for individuals with disabilities, including cognitive impairments, is equally important for their physical and mental well-being. What has not been established, however, is whether well-designed work can also enhance the cognitive abilities of individuals with cognitive impairments. Methods: Using a longitudinal study design, we investigated the impact of well-designed work on the cognitive abilities of 60 participants (operators) at the AMIPI Foundation factories, which employ individuals with cognitive impairments to produce electrical cables and harnesses for the automobile industry. The same operators were assessed at three different time points: upon hiring (n = 60), and after working in the factory for 1 year (n = 41, since 19 left the factory) and 2 years (n = 28, since 13 more left the factory). We used five cognitive tests evaluating: (1) finger and manual dexterity, bimanual dexterity, and procedural memory using the Purdue Pegboard; (2) sustained and selective attention using the Symbol Cancellation Task; (3) short- and long-term declarative verbal memory and long-term verbal recognition memory using Rey's Audio-Verbal Learning Test; (4) short- and long-term visual recognition memory using the Continuous Visual Memory Test; and (5) abstract reasoning using Raven's Standard Progressive Matrices. Results: We observed improvements in procedural memory, sustained and selective attention, and short- and long-term visual recognition memory after working in the factory for 1 or 2 years. We did not observe improvements in finger or manual dexterity or bimanual dexterity, nor short- or long-term declarative verbal memory or verbal recognition memory, nor abstract reasoning. Discussion: We conclude that, in addition to improving physical and mental well-being, well-designed manufacturing work can serve as a training intervention improving some types of cognitive functioning in individuals with cognitive impairments.

Can stimulants make you smarter, despite stealing your sleep?

Nonmedical use of psychostimulants for cognitive enhancement is widespread and growing in neurotypical individuals, despite mixed scientific evidence of their effectiveness. Sleep benefits cognition, yet the interaction between stimulants, sleep, and cognition in neurotypical adults has received little attention. We propose that one effect of psychostimulants, namely decreased sleep, may play an important and unconsidered role in the effect of stimulants on cognition. We discuss the role of sleep in cognition, the alerting effects of stimulants in the context of sleep loss, and the conflicting findings of stimulants for complex cognitive processes. Finally, we hypothesize that sleep may be one unconsidered factor in the mythology of stimulants as cognitive enhancers and propose a methodological approach to systematically assess this relation.

Efficacy of Digital and Non-Digital Compensatory Strategies in Supporting Prospective Memory Task Completion among Community-Dwelling Mid-Life and Older Adults.

OBJECTIVE: Compensatory strategies can be used to help mid-life and older adults successfully manage instrumental activities of daily living that rely upon prospective memory. This study compared the quality of digital and non-digital compensatory strategies in supporting accurate completion of naturalistic, real-world prospective memory tasks. METHOD: Participants included 70 community-dwelling mid-life and older adults. In this cross-sectional study, participants were tested remotely via Zoom in their homes. They were tasked with completing four real-world prospective memory tasks and encouraged to use their typical compensatory strategies. Utilized strategies were categorized, counted, and assigned quality scores (rating of thoroughness and utility), and prospective memory performance was coded. RESULTS: Participants who used any digital strategies utilized significantly more (ηp2 = .17) and better quality (ηp2 = .12) strategies than participants who did not use any digital strategies. However, the groups demonstrated equivalent prospective memory performance (ηp2 = .006). Within the digital group, participants' digital and non-digital strategies were of similar quality (d = .14) and resulted in similar prospective memory task accuracy (d = .01). CONCLUSIONS: Digital and non-digital strategies led to similar performance on naturalistic prospective memory tasks. Findings suggest that many different types of strategies can provide adequate prospective memory support to healthy mid-life and older adults. To inform development of compensatory strategy interventions, future studies should explore other factors that lead to successful prospective memory, such as the specific strategy type and task type match, across the continuum of cognitive impairment.

Martial Arts as a Tool for Enhancing Attention and Executive Function: Implications for Cognitive Behavioral Therapy - A Literature Review.

With a focus on its implications for cognitive behavioral therapy (CBT), this review study seeks to investigate the possible advantages of martial arts training on attention and executive function. Common cognitive impairments seen in a variety of psychiatric diseases, such as depression and attention deficit hyperactivity disorder, include difficulties in attention and executive function. Training in martial arts, which is known for its demanding physical and mental requirements, has drawn interest as a potential intervention for improving cognitive function. An overview of the most recent research on how martial arts training affects focus and executive function is given in this publication. The results demonstrate the potential of martial arts as a strategy for enhancing executive function and attention-related cognitive functions. The article also explores the implications of adding martial arts instruction to CBT therapies, arguing that doing so might be a beneficial supplementary strategy to improve treatment outcomes. With information on the possible advantages of martial arts training for attention and executive function, this review paper adds to the expanding corpus of research on non-pharmacological therapies for cognitive enhancement.

Exploring the influence of a 4-week aerobic exercise intervention on cognitive control processes in young adults: An SFT and DDM study.

Prior research has highlighted the potential impact of aerobic exercise on cognitive functioning, particularly in situations demanding heightened cognitive control. However, the mechanism underlying this cognitive enhancement has remained unknown. To address this issue, this study examined the impact of a 4-week aerobic exercise program on cognitive control processes in young male adults (aerobic exercise group: n=36, aged 21.42±1.13years) in comparison to a control group that received no treatment (n=33, aged 21.82±1.76years). We employed the redundant-target Stroop task to investigate inhibition processes at both perceptual and semantic stages. Utilizing systems factorial technology and the drift diffusion model, we assessed changes in resilience capacity and the underlying cognitive mechanisms. Our primary findings revealed a significant reduction in mean response times (RTs) in the aerobic exercise group, accompanied by a decrease in RT variability when inhibiting semantic processing. Resilience capacity significantly declined in both groups at similar levels. Notably, the aerobic exercise group exhibited an enhanced drift rate during automatic response inhibition and reduced non-decision time in the condition involving the inhibition of perceptual information. This study deepens our understanding of how a 4-week aerobic exercise program enhances cognitive control, affecting distinct cognitive processes, including processing speed, information accumulation during automatic response inhibition, and sensory and motor processes in perceptual conflicts. Our research underscores the potential of aerobic exercise as a means to boost cognitive control among young adults.

A precision-mapping approach to physical exercise interventions targeting cognitive function.

Physical exercise confers numerous benefits to brain structure, function and cognition, however, considerable individual variability exists in these effects. Emerging paradigms focused on intraindividual dynamics provide novel opportunities to map and leverage individualized neural architectures underlying exercise-cognition relationships. Progress at the intersection of psychometrics, structural and functional neuroimaging, electrophysiology, and genetics can be integrated to elucidate each individual's potential for improvement, as well as the specific abilities that are most likely to benefit from exercise regimens. These personalized profiles can then guide targeted exercise programs tailored to effectively modulate the pathways identified as most promising for that individual. Such mapping-guided exercise interventions tailored to a person's neurocognitive profile allows optimizing cognitive improvements compared to results elicited by generic regimens. While still in its infancy, precision interventions represent an innovative future direction to advance exercise in support of brain health, toward potent, truly personalized cognitive enhancement.

Neuroenhancement and mental health in students from four faculties - a cross-sectional questionnaire study.

Background: Students face great challenges at the beginning of and during their studies. Competitive experience, exam anxiety, and especially the new performance requirements often cause test anxiety and stressful experiences. The extent of substance use in terms of neuroenhancement (NE) is unclear. Evidence shows associations between NE, increased stress levels, and mental health. Objectives: We aim to determine the prevalence of NE and alcohol and tobacco use among college students. We also investigate the associations between NE and ADHD, anxiety, depression, and stress experience. Methods: In spring 2021, an anonymous online cross-sectional survey was conducted among students of medicine, dentistry, business economics, and business informatics in Würzburg. The survey included the instruments ASRS (ADHD), PSS-10 (stress), PHQ-4 (depression and anxiety), and AUDIT-C (alcohol comsumption), as well as questions about consumption patterns, prior knowledge, and reasons for NE. Results: Of the 5564 students who were invited to participate, 1010 completed the questionnaire (18.2%). Of these, 12.4% indicated NE for the studied period. NE was used in particular during preparations for exams, to enhance performance, and/or to regulate emotions, most commonly through caffeine tablets, cannabis, and methylphenidate. NE was associated with risky use of alcohol or tobacco, and to a lesser extent with ADHD symptoms and stress experience.Conclusions: Students are at risk of substance abuse and NE. Effective stress management and prevention approaches as well as low-threshold services are needed to identify and support students with risk profiles.

Enhancement of neurogenesis and cognition through intranasal co-delivery of galanin receptor 2 (GALR2) and neuropeptide Y receptor 1 (NPY1R) agonists: a potential pharmacological strategy for cognitive dysfunctions.

BACKGROUND: Spatial memory deficits and reduced neuronal survival contribute to cognitive decline seen in the aging process. Current treatments are limited, emphasizing the need for innovative therapeutic strategies. This research explored the combined effects of intranasally co-administered galanin receptor 2 (GALR2) and neuropeptide Y1 receptor (NPY1R) agonists, recognized for their neural benefits, on spatial memory, neuronal survival, and differentiation in adult rats. After intranasal co-delivery of the GALR2 agonist M1145 and a NPY1R agonist to adult rats, spatial memory was tested with the object-in-place task 3 weeks later. We examined neuronal survival and differentiation by assessing BrdU-IR profiles and doublecortin (DCX) labeled cells, respectively. We also used the GALR2 antagonist M871 to confirm GALR2's crucial role in promoting cell growth. RESULTS: Co-administration improved spatial memory and increased the survival rate of mature neurons. The positive effect of GALR2 in cell proliferation was confirmed by the nullifying effects of its antagonist. The treatment boosted DCX-labeled newborn neurons and altered dendritic morphology, increasing cells with mature dendrites. CONCLUSIONS: Our results show that intranasal co-delivery of GALR2 and NPY1R agonists improves spatial memory, boosts neuronal survival, and influences neuronal differentiation in adult rats. The significant role of GALR2 is emphasized, suggesting new potential therapeutic strategies for cognitive decline.

The Effects of Astaxanthin on Cognitive Function and Neurodegeneration in Humans: A Critical Review.

Oxidative stress is a key contributing factor in neurodegeneration, cognitive ageing, cognitive decline, and diminished cognitive longevity. Issues stemming from oxidative stress both in relation to cognition and other areas, such as inflammation, skin health, eye health, and general recovery, have been shown to benefit greatly from antioxidant use. Astaxanthin is a potent antioxidant, which has been outlined to be beneficial for cognitive function both in vitro and in vivo. Given the aforementioned promising effects, research into astaxanthin with a focus on cognitive function has recently been extended to human tissue and human populations. The present critical review explores the effects of astaxanthin on cognitive function and neurodegeneration within human populations and samples with the aim of deciphering the merit and credibility of the research findings and subsequently their potential as a basis for therapeutic use. Implications, limitations, and areas for future research development are also discussed. Key findings include the positive impacts of astaxanthin in relation to improving cognitive function, facilitating neuroprotection, and slowing neurodegeneration within given contexts.

Neuropeptide Y receptor 1 and galanin receptor 2 (NPY1R-GALR2) interactions in the dentate gyrus and their relevance for neurogenesis and cognition.

Introduction: This study may unveil novel insights into the interactions between neuropeptide Y receptor 1 (NPY1R) and galanin receptor 2 (GALR2), in the dentate gyrus of the dorsal hippocampus, shedding light on their role in neurogenesis and cognitive functions. Existing literature highlights the potential of these interactions in enhancing learning and memory, yet detailed mechanisms remain underexplored. Methods: Utilizing intracerebroventricular injections of GALR2 and NPY1R agonists in Sprague-Dawley male rats, we examined neurogenesis via markers PCNA and DCX, and memory consolidation through the object-in-place task over a three-week period. Results: Significant increases in NPY1R-GALR2 co-localization and neuroblast proliferation were observed, alongside enhanced memory consolidation. These findings suggest a synergistic effect of NPY1R and GALR2 activation on cognitive functions. Discussion: Our findings may foster the development of novel heterobivalent or multitargeting drugs, affecting NPY1R-GALR2 interaction, and suggest a future pharmacogical strategy for improving learning and memory found in many brain diseases. Further research is encouraged to explore these mechanisms in pathological models.

Cognitive Enhancement as Transformative Experience: The Challenge of Wrapping One's Mind Around Enhanced Cognition via Neurostimulation.

In this paper, the authors explore the question of whether cognitive enhancement via direct neurostimulation, such as through deep brain stimulation, could be reasonably characterized as a form of transformative experience. This question is inspired by a qualitative study being conducted with people at risk of developing dementia and in intimate relationships with people living with dementia (PLWD). They apply L.A. Paul's work on transformative experience to the question of cognitive enhancement and explore potential limitations on the kind of claims that can legitimately be made about individual well-being and flourishing, as well as limit the kind of empirical work-including the authors' own-that can hope to enlighten ethical discourse. In this paper, the authors advance the following theses: (1) it is sometimes reasonable to characterize cognitive enhancement as a transformative experience; (2) the testimonies of people intimately acquainted with dementia may still be relevant to evaluating cognitive enhancement even though cognitive enhancement may be a transformative experience; and (3) qualitative studies may still be useful in the ethical analysis of cognitive enhancement, but special attention may need to be given to how these are conducted and what kind of insights can be drawn from them.

Artificial Intelligence and Human Enhancement: Can AI Technologies Make Us More (Artificially) Intelligent?

This paper discusses two opposing views about the relation between artificial intelligence (AI) and human intelligence: on the one hand, a worry that heavy reliance on AI technologies might make people less intelligent and, on the other, a hope that AI technologies might serve as a form of cognitive enhancement. The worry relates to the notion that if we hand over too many intelligence-requiring tasks to AI technologies, we might end up with fewer opportunities to train our own intelligence. Concerning AI as a potential form of cognitive enhancement, the paper explores two possibilities: (1) AI as extending-and thereby enhancing-people's minds, and (2) AI as enabling people to behave in artificially intelligent ways. That is, using AI technologies might enable people to behave as if they have been cognitively enhanced. The paper considers such enhancements both on the level of individuals and on the level of groups.

Could psychostimulant drug use among university students be related to ADHD symptoms? A preliminary study.

We aimed to explore if psychostimulant use among student could be linked to attention deficit-hyperactivity disorder (ADHD) symptoms using a self-administered questionnaire sent by email to French students in 2021. Participants were asked about their psychostimulant use and the presence of ADHD symptoms using the Wender Utah Rating Scale and the Adult Self-Report Scale. Among the 4431 respondents, the prevalence of psychostimulant use was concerning and significantly associated with ADHD symptoms. This association could be related to undiagnosed ADHD or to psychobehavioral impairments induced by psychostimulant use underlining the need of ADHD screening and targeted prevention measures.

A new perspective for evaluating the efficacy of tACS and tDCS in improving executive functions: A combined tES and fNIRS study.

BACKGROUND: Executive function enhancement is considered necessary for improving the quality of life of patients with neurological or psychiatric disorders, such as attention-deficit/hyperactivity disorder, obsessive-compulsive disorder and Alzheimer's disease. Transcranial electrical stimulation (tES) has been shown to have some beneficial effects on executive functioning, but the quantification of these improvements remains controversial. We aimed to explore the potential beneficial effects on executive functioning induced by the use of transcranial alternating current stimulation (tACS)/transcranial direct current stimulation (tDCS) on the right inferior frontal gyrus (IFG) and the accompanying brain function variations in the resting state. METHODS: We recruited 229 healthy adults to participate in Experiments 1 (105 participants) and 2 (124 participants). The participants in each experiment were randomly divided into tACS, tDCS, and sham groups. The participants completed cognitive tasks to assess behavior related to three core components of executive functions. Functional near-infrared spectroscopy (fNIRS) was used to monitor the hemodynamic changes in crucial cortical regions in the resting state. RESULTS: Inhibition and cognitive flexibility (excluding working memory) were significantly increased after tACS/tDCS, but there were no significant behavioral differences between the tACS and tDCS groups. fNIRS revealed that tDCS induced decreases in the functional connectivity (increased neural efficiency) of the relevant cortices. CONCLUSIONS: Enhancement of executive function was observed after tES, and the beneficial effects of tACS/tDCS may need to be precisely evaluated via brain imaging indicators at rest. tDCS revealed better neural benefits than tACS during the stimulation phase. These findings might provide new insights for selecting intervention methods in future studies and for evaluating the clinical efficacy of tES.

Repetitive transcranial magnetic stimulation (rTMS) as a tool for cognitive enhancement in healthy adults: a review study.

As human beings, we have always sought to expand on our abilities, including our cognitive and motor skills. One of the still-underrated tools employed to this end is repetitive transcranial magnetic stimulation (rTMS). Until recently, rTMS was almost exclusively used in studies with rehabilitation purposes. Only a small strand of literature has focused on the application of rTMS on healthy people with the aim of enhancing cognitive abilities such as decision-making, working memory, attention, source memory, cognitive control, learning, computational speed, risk-taking, and impulsive behaviors. It, therefore, seems that the findings in this particular field are the indirect results of rehabilitation research. In this review paper, we have set to investigate such studies and evaluate the rTMS effectuality in terms of how it improves the cognitive skills in healthy subjects. Furthermore, since the most common brain site used for rTMS protocols is the dorsolateral prefrontal cortex (DLPFC), we have added theta burst stimulation (TBS) wave patterns that are similar to brain patterns to increase the effectiveness of this method. The results of this study can help people who have high-risk jobs including firefighters, surgeons, and military officers with their job performance.

Efecto del resveratrol sobre las funciones cognitivas en adultos mayores: una revisión sistemática y metaanálisis / Effect of resveratrol on cognitive functions in older adults: a systematic review and meta-analysis

Introducción: el resveratrol tiene múltiples efectos beneficiosos en diferentes sistemas del organismo, incluido el nervioso central, sin embargo, los resultados reportados sobre el efecto en las funciones cognitivas en adultos mayores son inconsistentes. Por lo anterior, el propósito de esta revisión sistemática es presentar una síntesis del conocimiento sobre los efectos del resveratrol en las funciones cognitivas en adultos mayores. Método: se llevó a cabo una revisión sistemática acorde con los criterios de PRISMA-2009. La búsqueda de artículos se realizó hasta el 7 de septiembre de 2021 en PubMed, Scopus, Web of Science, PsycINFO, SciELO y TESIUNAM. Las variables de desenlace fueron memoria diferida, inmediata y de trabajo y velocidad del procesamiento. Se estimó la diferencia de medias estandarizadas (DME) para evaluar el efecto. Resultados: se encontraron 1.065 estudios, de los cuales seis cumplieron los criterios de elegibilidad para la revisión sistemática y metaanálisis. No se encontró un efecto significativo en la memoria diferida (DME = 0,69, IC 95 %: 0,85-2,23, p = 0,38), memoria inmediata (DME = 0,56, IC 95 %: -0,20-1,31, p = 0,15), memoria de trabajo (DME = -0,21, IC 95 %: -0,74-0,32, p = 0,43) y velocidad de procesamiento (DME = 0,25, IC 95 %: -0,58-1,07, p = 0,55). Conclusión: nuestros resultados sugieren que el resveratrol no tiene un efecto sobre las funciones cognitivas en adultos mayores. No obstante, es necesario realizar más estudios con diferentes dosis, tipos de formulación del nutracéutico y tiempo de tratamiento. (AU)

Introduction: resveratrol has multiple beneficial effects on different body systems, including the central nervous system, however, the results reported on the effect on cognitive functions in older adults are inconsistent. Therefore, the purpose of this systematic review is to present a synthesis of knowledge about the effect of resveratrol on cognitive functions in older adults. Method: a systematic review was carried out according to the PRISMA-2009 criteria. The search for articles was carried out until September 7, 2021 in PubMed, Scopus, Web of Science, PsycINFO, SciELO, and TESIUNAM. The outcome variables were delayed, immediate, and working memory, and processing speed. The standardized mean difference (SMD) was estimated to assess the effect. Results: one thousand sixty-five studies were found, of which six met the eligibility criteria for the systematic review and meta-analysis. No significant effect was found on delayed memory (SMD = 0.69, 95 % CI: 0.85-2.23, p = 0.38), immediate memory (SMD = 0.56, 95 % CI: -0.20-1.31, p = 0.15), working memory (SMD = -0.21, 95 % CI: -0.74-0.32, p = 0.43) and processing speed (SMD = 0.25, 95 % CI: -0.58-1.07, p = 0.55). Conclusion: our results suggest that resveratrol does not have an effect on cognitive functions in older adults, however, it is necessary to carry out more studies with different doses, type of nutraceutic. (AU)

Sex matters for the enhancement of cognitive training with transcranial direct current stimulation (tDCS).

BACKGROUND: Transcranial direct current stimulation (tDCS) can influence brain network activity and associated cognitive and behavioural functions. In addition to the extensive variety in stimulation parameters, numerous biological factors drive these effects, however these are yet poorly understood. Here, we investigate one of the major biological factors by focusing on sex-dependent effects of tDCS on a challenging cognitive control task (adaptive paced auditory serial addition task [PASAT]) in healthy humans. METHODS: This sex-specific re-analysis was performed on data of 163 subjects who underwent a 2-week cognitive control training (6 sessions in total). Subjects received either verum (anodal/cathodal) or sham tDCS. Electrodes were placed over the left or right dorsolateral prefrontal cortex and the respective contralateral deltoid muscle. Cognitive control was measured as performance in the PASAT and was analysed in respect to stimulation conditions (sham, anodal, cathodal) and sex. RESULTS: Regardless of stimulation condition, performance gains between the sexes were higher in females compared to males (p = 0.0038). Female's performance during anodal tDCS exceeded male's (p = 0.0070), yet no effects were found for cathodal or sham tDCS. Moreover, in females we found a superior effect for anodal tDCS over sham stimulation (fanodal: p = 0.0354; fcathodal: p = 0.6181), but no such effect in males (manodal: p = 0.6882; mcathodal: p = 0.4822). CONCLUSIONS: This study highlights the relevance of biological sex for the effects of tDCS on cognitive training. Thus, an increased attention to biological sex is advisable in future brain stimulation research to highlight and in consequence better understand potentially underlying sex-specific mechanisms. Considering biological sex will further advance customisation and individualisation of tDCS interventions. Trial registration ClinicalTrials.gov, NCT04108663.

In previous studies, brain stimulation techniques like transcranial direct current stimulation (tDCS) have been shown to support cognitive trainings. However, these effects are rather small and vary between people. A key factor of variability is the biological sex. Hence, in this study we were interested in whether the effects of tDCS differ between females and males. To answer this research question, we analysed the data of 163 human subjects who underwent a 2-week cognitive control training program, which incorporates a challenging cognitive task (the adaptive paced auditory serial addition task [PASAT]). During the PASAT, subjects have to solve a stressful calculation exercise. Concurrently to solving this task, the subjects received either real (further divided into anodal [= enhancing] and cathodal [= inhibiting]) or placebo tDCS. We found that females had greater performance gains in the task than males, regardless of the type of tDCS they received. Furthermore, females performed particularly well when they received anodal tDCS, but there were no significant effects for cathodal or placebo tDCS. For males, we did not find any significant benefits of tDCS. These findings highlight the importance of considering biological sex in future brain stimulation research and suggest that biological sex is an important component to consider when studying the effects of tDCS. By paying more attention to this factor, researchers can better understand how tDCS works and develop more effective and personalised interventions.