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Although mobile phone (MP) use has been steadily increasing in the last decades and similar positive trends are expected for the near future, systematic investigations on neurophysiological and cognitive effects caused by recently developed technological standards for MPs are scarcely available. Here, we investigated the effects of radiofrequency (RF) fields emitted by new-generation mobile technologies, specifically, Universal Mobile Telecommunications System (UMTS) and Long-Term Evolution (LTE), on intrinsic scalp EEG activity in the alpha band (8–12 Hz) and cognitive performance in the Stroop test. The study involved 60 healthy, young-adult university students (34 for UMTS and 26 for LTE) with double-blind administration of Real and Sham exposure in separate sessions. EEG was recorded before, during and after RF exposure, and Stroop performance was assessed before and after EEG recording. Both RF exposure types caused a notable decrease in the alpha power over the whole scalp that persisted even after the cessation of the exposure, whereas no effects were found on any aspects of performance in the Stroop test. The results imply that the brain networks underlying global alpha oscillations might require minor reconfiguration to adapt to the local biophysical changes caused by focal RF exposure mimicking MP use.

Millions of people use mobile phones (MP) while drinking coffee or other caffeine containing beverages. Little is known about the potential combined effects of MP irradiation and caffeine on cognitive functions. Here we investigated whether caffeine intake and concurrent exposure to Universal Mobile Telecommunications System (UMTS) MP-like irradiation may interactively influence neuro-cognitive function in an active visual oddball paradigm. In a full factorial experimental design, 25 participants performed a simple visual target detection task while reaction time (RT) and electroencephalogram (EEG) was recorded. Target trials were divided into Low and High probability sets based on target-to-target distance. We analyzed single trial RT and alpha-band power (amplitude) in the pre-target interval. We found that RT was shorter in High vs. Low local probability trials and caffeine further shortened RT in High probability trials relative to the baseline condition suggesting that caffeine improves the efficiency of implicit short-term memory. Caffeine also decreased pre-target alpha amplitude resulting in higher arousal level. Furthermore, pre-target gamma power positively correlated with RT, which may have facilitated target detection. However, in the present pharmacologically validated study UMTS exposure either alone or in combination with caffeine did not alter RT or pre-stimulus oscillatory brain activity.

Mobile equipment use of wireless fidelity (Wi-Fi) signal modulation has increased exponentially in the past few decades. However, there is inconclusive scientific evidence concerning the potential risks associated with the energy deposition in the brain from Wi-Fi and whether Wi-Fi electromagnetism interacts with cognitive function. In this study we investigated possible neurocognitive effects caused by Wi-Fi exposure. First, we constructed a Wi-Fi exposure system from commercial parts. Dosimetry was first assessed by free space radiofrequency field measurements. The experimental exposure system was then modeled based on real geometry and physical characteristics. Specific absorption rate (SAR) calculations were performed using a whole-body, realistic human voxel model with values corresponding to conventional everyday Wi-Fi exposure (peak SAR10g level was 99.22 mW/kg with 1 W output power and 100% duty cycle). Then, in two provocation experiments involving healthy human volunteers we tested for two hypotheses: 1. Whether a 60 min long 2.4 GHz Wi-Fi exposure affects the spectral power of spontaneous awake electroencephalographic (sEEG) activity (N = 25); and 2. Whether similar Wi-Fi exposure modulates the sustained attention measured by reaction time in a computerized psychomotor vigilance test (PVT) (N = 19). EEG data were recorded at midline electrode sites while volunteers watched a silent documentary. In the PVT task, button press reaction time was recorded. No measurable effects of acute Wi-Fi exposure were found on spectral power of sEEG or reaction time in the psychomotor vigilance test. These results indicate that a single, 60 min Wi-Fi exposure does not alter human oscillatory brain function or objective measures of sustained attention.

This work evaluates the complex exposure characteristics of Wireless Local Area Network (WLAN) technology and describes the design of a WLAN exposure system built using commercially available modular parts for the study of possible biological health effects due to WLAN exposure in a controlled environment. The system consisted of an access point and a client unit (CU) with router board cards types R52 and R52n with 18 dBm and 25 dBm peak power, respectively. Free space radiofrequency field (RF) measurements were performed with a field meter at a distance of 40 cm from the CU in order to evaluate the RF exposure at several signal configurations of the exposure system. Finally, the specific absorption rate (SAR) generated by the CU was estimated computationally in the head of two human models. Results suggest that exposure to RF fields of WLAN systems strongly depends on the sets of the router configuration: the stability of the exposure was more constant and reliable when both antennas were active and vertically positioned, with best signal quality obtained with the R52n router board at channel 9, in UDP mode. The maximum levels of peak SAR were far away from the limits of international guidelines with peak levels found over the skin.

Napjainkban mobiltelefonok életünk szerves részét képezik, hiszen 2014-re a világban közel 7 milliárd mobil-elofizetés van ˝ 1. A telefonok fejhez való közelsége miatt a használók feje magas frekvenciás elektromágneses (EM) tér hatásának van kitéve, mely elektromos és ezáltal fiziológiai elváltozásokat okozhat az agyban. Habár számos tanulmány vizsgálta a különbözo˝ mobiltelefonok keltette EM tér agyi funkciókra gyakorolt hatását, az eredmények ellentmondóak. Továbbá a 3. generációs (3G) UMTS típusú sugárzás magasabb idegi m ˝uködésekre gyakorolt hatásait csak kevés tanulmány vizsgálta.Jelen munkánkban arra kerestük a választ, hogy a 3G UMTS mobiltelefonos besugárzás miként tudja módosítani a kognitív funkciók elektrofiziológiai és magatartásbeli korrelátumait. Az elso vizsgálatban az UMTS EM tér spontán agyi aktivitásra gyakorolt hatásait vizsgáltuk, mely az ˝ aktuális tudati állapot érzékeny méroje. Azonban a mobiltelefon nem tudta módosítani az EEG ˝ frekvenciatartományok fobb amplitúdóit. A második mérésben az UMTS EM tér automatikus ˝ változásdetektálásra (MMN) és automatikus figyelmi váltásra (P3a) gyakorolt hatásait vizsgáltuk. Összhangban az irodalommal mi sem tudtuk igazolni, hogy az UMTS tér hatással lenne az auditoros információfeldolgozásra. A harmadik vizsgálatban azzal a hipotézissel éltünk, hogy ha az UMTS EM tér önmagában az agyi fiziológiát nem képes módosítani, akkor esetleg más, nem EM környezeti ágensekkel még mindig additív, vagy szinergista módon serkento interakci- ˝ óba léphet, mely a sejtszint ˝u funkciókat tekintve hasonló lehet az EM térrel. Ennek vizsgálatára kifejlesztettünk egy új mérési módszert. Így tesztelni tudtuk a hipotézisünket a magasabb rend ˝u vizuális információfeldolgozási folyamatokra. Esetünkben a koffeint választottuk, mivel ez a leggyakrabban használt központi idegrendszeri stimuláns, továbbá napi szinten elofordul, hogy ˝ koffein tartalmú terméket fogyasztunk és közben használjuk a telefonunkat. A vizsgálati eredményeink nem igazolják, hogy az UMTS EM tér módosítani tudja a koffein stimuláló hatását a vizuális rendszerben.Összességében elmondhatjuk, hogy egyrészt az akut, jól kontrollált UMTS besugárzás önállóan nem képes módosítani az információfeldolgozás magatartásbeli és fiziológiai korrelátumait. Így a kognitív teljesítményt és a spontán EEG-t, auditoros és vizuális kiváltott válaszokat. Továbbá az EM tér nem képes módosítani a koffein élénkíto hatásait sem pro sem kontra. A negatív ˝ eredmények interpretálásakor két fajta megközelítéssel élhetünk. Az egyik, az általunk használt EM tér 1) teljesítményének alacsony volta és/vagy 2) hatástalan modulációja, mely nem képes elérni azt az idegi m ˝uködés szempontjából fontos küszöbszintet, ami biológiai hatást válthatna ki.Habár az UMTS EM tér nem tudta módosítani az információfeldolgozást - a GSM tanulmányoknál tapasztalt fiziológiai hatások miatt - egyértelm ˝uen nem tudjuk kijelenteni, hogy a mobiltelefonok keltette EM térek nem módosítják az agyi információfeldolgozási folyamatokat. Ennek tükrében mindenképpen további tanulmányok elvégzése szükséges, melyekben különbözo kime- ˝ neti EM teljesítményeket és modulációkat kellene vizsgálni önmagukban vagy más környezeti ágensekkel kombinálva.

Intracranial neurophysiological recordings require chronic implants to provide transcranial access to the brain. Especially in larger animals, which participate in experiments over extended periods of time, implants should match the skull curvature to promote osseointegration and avoid tissue and bacterial ingress over time. Proposed CAD methods for designing implants to date have focused on naïve animals with continuous and even skull surfaces and calculate Boolean differences between implant and skull surface to fit the implant to the skull curvature. However, custom-fitting by calculating the difference fails, if a discontinuous skull surface needs to be matched. Also, the difference method does not allow designs with constant material thickness along the skull curvature, e.g. to allow fixed screw lengths. We present a universal step-by-step guide for custom-fitting implants which overcomes these limitations. It is suited for unusual skull conditions, like surface discontinuities or irregularities and includes virtual bending as a process to match skull surfaces while maintaining implant thickness. We demonstrate its applicability for a wide spectrum of scenarios, ranging from complex-shaped single-pieced implants to detailed multi-component implant systems built on even or discontinuous skull. The guide uses only a few software tools and the final virtual product can be manufactured using CNC milling or 3D printing. A detailed description of this process is available on GitHub including step-by-step video instructions suitable for users without any prior knowledge in CAD programming. We report the experience with these implants over several years in 11 rhesus monkeys. Chronic implants are essential for intracranial neurophysiological recordings. In this study we show how to custom-design and –fit such implants for rhesus monkeys (Macacca mulatta). Different to existing approaches, our procedure is not limited to even skull surfaces but can be applied to discontinuous or irregular surfaces. It furthermore presents a description of virtual implant bending to match the skull curvature while maintaining implant thickness. The final virtual product can be manufactured using CNC milling or 3D printing. In contrast to previous studies, this guide is suited for users without any prior expertise in CAD programming using our step-by-step video instructions.

Cholinergic neuromodulation is known to play a key role in visual working memory (VWM) — keeping relevant stimulus representations available for cognitive processes for short time periods up to a few minutes. Despite the growing body of evidence on how the neural and cognitive mechanisms of VWM dynamically change over retention time, there is mixed evidence available on cholinergic effects as a function of VWM delay period in non-human primates. Using the delayed matching to sample VWM task in rhesus macaques (N=6), we aimed to characterize VWM maintenance in terms of performance changes as a function of delay duration (across a wide range of delays from 1 to 76 s). Then, we studied how cholinergic neuromodulation influences VWM maintenance using the muscarinic receptor antagonist scopolamine administered alone as transient amnestic treatment, and in combination with two doses of the acetylcholinesterase inhibitor donepezil, a widely used Alzheimer's medication probing for the reversal of scopolamine-induced impairments. Results indicate that scopolamine-induced impairments of VWM maintenance are delay-dependent and specifically affect the 15-33 s time range, suggesting that scopolamine worsens the normal decay of VWM with the passage of time. Donepezil partially rescued the observed scopolamine-induced impairments of VWM performance. These results provide strong behavioral evidence for the role of increased cholinergic tone and muscarinic neuromodulation in the maintenance of VWM beyond a few seconds, in line with our current knowledge on the role of muscarinic acetylcholine receptors in sustained neural activity during VWM delay periods. Competing Interest Statement B.L. and G.L. are employees of Gedeon Richter Plc. This does not alter our adherence to journal policies on sharing data and materials. The remaining authors (V.O., B.K., A.T., I.H.) declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

The ability to promptly respond to behaviourally relevant events depends on both general alertness and phasic changes in attentional state driven by temporal expectations. Using a variable foreperiod simple reaction time (RT) task in four adult male rhesus macaques, we investigated the role of the cholinergic system in alertness and temporal expectation. Foreperiod-effects on RT reflect temporal expectation, while alertness is quantified as overall response speed. We measured these RT parameters under vehicle treatment and systemic administration of the muscarinic receptor antagonist scopolamine. We also investigated whether and to what extent the effects of scopolamine were reversed by donepezil, a cholinesterase inhibitor widely used for the treatment of dementia. In the control condition, RT showed a continuous decrease as the foreperiod duration increased, which clearly indicated the effect of temporal expectation on RT. This foreperiod effect was mainly detectable on the faster tail of the RT distribution and was eliminated by scopolamine. Furthermore, scopolamine treatment slowed down the average RT. Donepezil treatment was efficient on the slower tail of the RT distribution and improved scopolamine-induced impairments only on the average RT reflecting a general beneficial effect on alertness without any improvement in temporal expectation. The present results highlight the role of the cholinergic system in temporal expectation and alertness in primates and help delineate the efficacy and scope of donepezil and other cholinomimetic agents as cognitive enhancers in present and future clinical practice. Competing Interest Statement B.L. is employee of Gedeon Richter Plc. This does not alter our adherence to journal policies on sharing data and materials. The remaining authors (V.O., B.K., A.T., I.H.) declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Although mobile phone (MP) use has been steadily increasing in the last decades and similar positive trends are expected for the near future, systematic investigations on neurophysiological and cognitive effects caused by recently developed technological standards for MPs are scarcely available. Here, we investigated the effects of radiofrequency (RF) fields emitted by new-generation mobile technologies, specifically, Universal Mobile Telecommunications System (UMTS) and Long-Term Evolution (LTE), on intrinsic scalp EEG activity in the alpha band (8-12 Hz) and cognitive performance in the Stroop test. The study involved 60 healthy, young-adult university students (34 for UMTS and 26 for LTE) with double-blind administration of Real and Sham exposure in separate sessions. EEG was recorded before, during and after RF exposure, and Stroop performance was assessed before and after EEG recording. Both RF exposure types caused a notable decrease in the alpha power over the whole scalp that persisted even after the cessation of the exposure, whereas no effects were found on any aspects of performance in the Stroop test. The results imply that the brain networks underlying global alpha oscillations might require minor reconfiguration to adapt to the local biophysical changes caused by focal RF exposure mimicking MP use.