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Effectively applied transcranial electrical stimulation yields potential for enhancing the function of various cognitive domains, making it a promising point of investigation in the field of neuroscience. The current study explored the comparative effectiveness of theta (7 Hz) and gamma (40 Hz) transcranial alternating current stimulation (tACS) in enhancing the features of working memory (WM), specifically the central executive and visuospatial components, as assessed by a 2-back task. Frontofrontal tACS was employed to investigate the impact of these two frequency bands on a sample of 112 healthy participants in the age range of 18-20 years. Our findings provide support for WM improvement as both frontal theta-tACS and gamma-tACS exhibited superior outcomes when compared to sham stimulation. Furthermore, stronger improvements in WM were observed in the context of 40 Hz stimulation as contrasted with 7 Hz stimulation during both online and post-stimulation assessments. Overall, we observed that the initial online enhancements in cognitive performance are associated with entrainment, whereas long-term offline effects are attributed to plasticity. This study contributes to the evolving landscape of tACS research and emphasizes the need for further investigations into the intricate interactions between tACS parameters, task load, and individual characteristics to enhance the therapeutic potential of neuromodulation techniques for WM enhancement. [ABSTRACT FROM AUTHOR]

Working memory is a cognitive process that involves short-term active maintenance, flexible updating, and processing of goal- or task-relevant information. All frequency bands are involved in working memory. The activities of the theta and gamma frequency bands in the frontoparietal network are highly involved in working memory processes; theta oscillations play a role in the temporal organization of working memory items, and gamma oscillations influence the maintenance of information in working memory. Transcranial alternating current stimulation (tACS) results in frequency-specific modulation of endogenous oscillations and has shown promising results in cognitive neuroscience. The electrophysiological and behavioral changes induced by the modulation of endogenous gamma frequency in the prefrontal cortex using tACS have not been extensively studied in the context of working memory. Therefore, we aimed to investigate the effects of frontal gamma-tACS on working memory outcomes. We hypothesized that a 10-min gamma tACS administered over the frontal cortex would significantly improve working memory outcomes. Young healthy participants performed Luck–Vogel cognitive behavioral tasks with simultaneous pre- and post-intervention EEG recording (Sham versus 40 Hz tACS). Data from forty-one participants: sham (15 participants) and tACS (26 participants), were used for the statistical and behavioral analysis. The relative changes in behavioral outcomes and EEG due to the intervention were analyzed. The results show that tACS caused an increase in the power spectral density in the high beta and low gamma EEG bands and a decrease in left-right coherence. On the other hand, tACS had no significant effect on success rates and response times. Conclusion: 10 min of frontal 40 Hz tACS was not sufficient to produce detectable behavioral effects on working memory, whereas electrophysiological changes were evident. The limitations of the current stimulation protocol and future directions are discussed in detail in the following sections. [ABSTRACT FROM AUTHOR]

Phosphene is the experience of light without natural visual stimulation. It can be induced by electrical stimulation of the retina, optic nerve or cortex. Induction of phosphenes can be potentially used in assistive devices for the blind. Analysis of phosphene might be beneficial for practical reasons such as adjustment of transcranial alternating current stimulation (tACS) frequency and intensity to eliminate phosphene perception (e.g., tACS studies using verum tACS group and sham group) or, on the contrary, to maximize perception of phosphenes in order to be more able to study their dynamics. In this study, subjective reports of 50 healthy subjects exposed to different intensities of retinal tACS at 4 different frequencies (6, 10, 20 and 40 Hz) were analyzed. The effectiveness of different tACS frequencies in inducing phosphenes was at least 92 %. Subject reported 41 different phosphene types; the most common were light flashes and light circles. Changing the intensity of stimulation often induced a change in phosphene attributes. Up to nine phosphene attributes changed when the tACS intensity was changed. Significant positive correlation was observed between number of a different phosphene types and tACS frequency. Based on these findings, it can be concluded that tACS is effective in eliciting phosphenes whose type and attributes change depending on the frequency and intensity of tACS. The presented results open new questions for future research. [ABSTRACT FROM AUTHOR]

The territory of the Czech Republic was contaminated as a result of the breakdown in the Chernobyl nuclear power plant in 1986. The Czech population received low doses of ionising radiation which, though it could not cause a deterministic impact, could have had stochastic effects expressed in the years following the accident. Twenty years after the accident is a long enough time to assess its stochastic effects, primarily tumours and genetic impairment. The moderate amount of radioactive fallout received by the Czech population in 1986 increased thyroid cancer in the following years; on the other hand, no obvious genetic impact was found. [ABSTRACT FROM AUTHOR]

Treatment of pain is one of the most important aims of medicine. Over the past several decades, invasive, semi-invasive and non-invasive brain stimulation methods have been tested and implemented for modulation of the pain. In this review, we bring an overview of those methods including stimulation of both deep brain structures utilizing invasive and semi-invasive techniques and the brain cortex stimulated by non-invasive transcranial magnetic and electrical techniques. Another potentially beneficial method that could modulate pain by stimulating the deep brain with interferential transcranial alternating current is discussed as well.