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Abstract: Different kinds of challenge can alter spontaneous ongoing electroencephalographic (EEG) rhythms in animal models, thus providing paradigms to evaluate treatment effects in drug discovery. The effects of challenges represented by pharmacological agents, hypoxia, sleep deprivation and transcranial magnetic stimulation (TMS) on EEG rhythms are here reviewed to build a knowledge platform for innovative translational models for drug discovery in Alzheimer’s disease (AD). It has been reported that antagonists of cholinergic neurotransmission cause synchronisation of spontaneous ongoing EEG rhythms in terms of enhanced power of EEG low frequencies and decreased power of EEG high frequencies. Acetylcholinesterase inhibitors and serotonergic drugs may restore a normal pattern of EEG desynchronisation. Sleep deprivation and hypoxia challenges have also been reported to elicit abnormal synchronisation of spontaneous ongoing EEG rhythms in rodents. The feasibility and reproducibility of TMS have been demonstrated in rodents but information on a consistent modulation of EEG after TMS manipulation is very limited. Transgenic mice over-expressing human amyloid precursor protein complementary DNAs (cDNAs) harbouring the ‘Swedish’ mutation and PS-1 cDNAs harbouring the A264E mutation, which recapitulate some of the pathological features of AD, exhibit alterations of spontaneous ongoing EEG rhythms at several low and high frequencies. This does not appear, however, to be a consequence of beta-amyloid deposition in the brain. The present review provides a critical evaluation of changes of spontaneous ongoing EEG rhythms due to the experimental manipulations described above, in order to stimulate the promote more adherent models fitting dynamics in humans. [Copyright &y& Elsevier]

Abstract: Objective: The “neural efficiency” hypothesis posits that neural activity is reduced in experts. Here we tested the hypothesis that compared with non-athletes, elite athletes are characterized by a reduced cortical activation during simple voluntary movement and that this is reflected by the modulation of dominant alpha rhythms (8–12Hz). Methods: EEG data (56 channels; EB-Neuro) were continuously recorded in the following right-handed subjects: 10 elite karate athletes and 12 non-athletes. During the EEG recordings, they performed brisk voluntary wrist extensions of the right or left hand (right movement and left movement). The EEG cortical sources were estimated by standardized low-resolution brain electromagnetic tomography (sLORETA) freeware. With reference to a baseline period, the power decrease of alpha rhythms during the motor preparation and execution indexed the cortical activation (event-related desynchronization, ERD). Results: During both preparation and execution of the right movements, the low- (about 8–10Hz) and high-frequency alpha ERD (about 10–12Hz) was lower in amplitude in primary motor area, in lateral and medial premotor areas in the elite karate athletes than in the non-athletes. For the left movement, only the high-frequency alpha ERD during the motor execution was lower in the elite karate athletes than in the non-athletes. Conclusions: These results confirmed that compared with non-athletes, elite athletes are characterized by a reduced cortical activation during simple voluntary movement. Significance: Cortical alpha rhythms are implicated in the “neural efficiency” of athletes’ motor systems. [Copyright &y& Elsevier]

Alzheimer's disease (AD) induces a widespread pathological extracellular accumulation of beta-amyloid (Aβ) peptides that affects cortical networks underpinning cognitive functions. This is related to abnormal functional and effective brain connectivity as revealed by graph markers of resting-state eyes-closed electroencephalographic (EEG) rhythms. Here we revised EEG studies in mild cognitive impairment and AD subjects showing that these markers are promising network disease endpoints for basic research and AD drug discovery. [ABSTRACT FROM AUTHOR]

Abstract: Here we tested two working hypotheses on spatially selective cortical activation (“neural efficiency”) in experts: (i) compared to non-athletes, elite karate athletes are characterized by a reduced cortical activation during the judgment of karate actions; (ii) compared to non-athletes and elite karate athletes, amateur karate athletes are characterized by an intermediate cortical activation during the judgment of karate actions. Electroencephalographic (EEG) data were recorded in 16 elite karate athletes, 15 amateur athletes and 17 non-athletes. They observed a series of 120 karate videos. At the end of each video, the subjects had to judge the technical/athletic level of the exercise by a scale from 0 to 10. The mismatch between their judgment and that of the coach indexed the degree of action judgment. The EEG cortical sources were estimated by sLORETA. With reference to a pre-stimulus period, the power decrease of alpha (8–12Hz) rhythms during the video indexed the cortical activation (event-related desynchronization, ERD). Regarding the hypothesis of reduced activity in elite karate athletes, low- and high-frequency alpha ERD was less pronounced in dorsal and “mirror” pathways in the elite karate athletes than in the non-athletes. Regarding the hypothesis of intermediate cortical activity in amateur karate athletes, low- and high-frequency alpha ERD was less pronounced in dorsal pathways across the non-athletes, the amateur karate athletes, and the elite karate athletes. In conclusion, athletes’ judgment of observed sporting actions is related to less pronounced alpha ERD, as a possible index of “neural efficiency” in experts engaged in social cognition. [Copyright &y& Elsevier]

Resting state electroencephalographic (EEG) rhythms reflect the fluctuation of cortical arousal and vigilance in a typical clinical setting, namely the EEG recording for few minutes with eyes closed (i.e., passive condition) and eyes open (i.e., active condition). Can this procedure be back-translated to C57 (wild type) mice for aging studies? On-going EEG rhythms were recorded from a frontoparietal bipolar channel in 85 (19 females) C57 mice. Male mice were subdivided into 3 groups: 25 young (4.5–6 months), 18 middle-aged (12–15 months), and 23 old (20–24 months) mice to test the effect of aging. EEG power density was compared between short periods (about 5 minutes) of awake quiet behavior (passive) and dynamic exploration of the cage (active). Compared with the passive condition, the active condition induced decreased EEG power at 1–2 Hz and increased EEG power at 6–10 Hz in the group of 85 mice. Concerning the aging effects, the passive condition showed higher EEG power at 1–2 Hz in the old group than that in the others. Furthermore, the active condition exhibited a maximum EEG power at 6–8 Hz in the former group and 8–10 Hz in the latter. In the present conditions, delta and theta EEG rhythms reflected changes in cortical arousal and vigilance in freely behaving C57 mice across aging. These changes resemble the so-called slowing of resting state EEG rhythms observed in humans across physiological and pathological aging. The present EEG procedures may be used to enhance preclinical phases of drug discovery in mice for understanding the neurophysiological effects of new compounds against brain aging. [ABSTRACT FROM AUTHOR]

Abstract: Cortical sources of resting state electroencephalographic (EEG) rhythms are abnormal in subjects with mild cognitive impairment (MCI). Here, we tested the hypothesis that these sources in amnesic MCI subjects further deteriorate over 1 year. To this aim, the resting state eyes-closed EEG data were recorded in 54 MCI subjects at baseline (Mini Mental State Examination I = 26.9; standard error [SE], 0.2) and at approximately 1-year follow-up (13.8 months; SE, 0.5; Mini Mental State Examination II = 25.8; SE, 0.2). As a control, EEG recordings were also performed in 45 normal elderly and in 50 mild Alzheimer's disease subjects. EEG rhythms of interest were delta (2–4 Hz), theta (4–8 Hz), alpha1 (8–10.5 Hz), alpha2 (10.5–13 Hz), beta1 (13–20 Hz), and beta2 (20–30 Hz). Cortical EEG sources were estimated using low-resolution brain electromagnetic tomography. Compared with the normal elderly and mild Alzheimer's disease subjects, the MCI subjects were characterized by an intermediate power of posterior alpha1 sources. In the MCI subjects, the follow-up EEG recordings showed a decreased power of posterior alpha1 and alpha2 sources. These results suggest that the resting state EEG alpha sources were sensitive—at least at the group level—to the cognitive decline occurring in the amnesic MCI group over 1 year, and might represent cost-effective, noninvasive and widely available markers to follow amnesic MCI populations in large clinical trials. [Copyright &y& Elsevier]

Abstract: Objective: Obese subjects without eating disorders were characterised by poor electroencephalographic (EEG) alpha rhythms during resting-state eye-closed condition (Babiloni et al., 2011b). Is this true also for the desynchronisation of alpha rhythms during resting-state eyes opening? Methods: EEG data were recorded in 15 underweight, 20 normal-weight, and 18 overweight/obese subjects during resting-state eyes-closed and -open conditions. EEG sources were estimated by LORETA for alpha 1 (8–10.5Hz) and alpha 2 (10.5–13Hz). The alpha desynchronisation was calculated as the difference eyes-open minus -closed condition. Results: The occipital alpha 1 desynchronisation was lower in overweight/obese and underweight subjects compared with normal-weight subjects (p <0.000005). The same was true for parietal, occipital and temporal alpha 2 (10.5–13Hz) desynchronisation (p <0.000002). The parietal and temporal alpha 1 desynchronisation was lower in overweight/obese than in normal-weight subjects (p <0.00001). These effects spatially matched those observed in the resting-state eyes-closed condition. Conclusion: Subjects with abnormal weight and normal eating behaviour are characterised by poor alpha desynchronisation during resting-state eyes opening. Significance: Obese subjects without eating disorders show abnormal mechanisms of cortical neural synchronisation and desynchronisation of alpha rhythms in the resting state condition. [Copyright &y& Elsevier]

Abstract: Acetylcholinesterase inhibitors (AChEIs) are the most widely used symptomatic treatment for mild to severe Alzheimer’s disease (AD) patients, while N-methyl-d-aspartic acid (NMDA) receptor antagonist memantine is licensed for use in moderate to severe AD patients. In this article, the effect of these compounds on resting state eyes-closed electroencephalographic (EEG) rhythms in AD patients is reviewed to form a knowledge platform for the European Innovative Medicine Initiative project “PharmaCog” (IMI Grant Agreement No. 115009) aimed at developing innovative translational models for drug testing in AD. Indeed, quite similar EEG experiments and the same kind of spectral data analysis can be performed in animal models of AD and in elderly individuals with prodromal or manifest AD. Several studies have shown that AChEIs affect both resting state EEG rhythms and cognitive functions in AD patients. After few weeks of successful treatment, delta (0–3Hz) or theta (4–7Hz) rhythms decrease, dominant alpha rhythms (8–10Hz) increase, and cognitive functions slightly improve. Beneficial effects of these rhythms and cognitive functions were also found in AD responders to the long-term successful treatment (i.e. 6–12months). In contrast, only one study has explored the long-term effects of memantine on EEG rhythms in AD patients, showing reduced theta rhythms. The present review enlightens the expected effects of AChEIs on resting state EEG rhythms in AD patients as promising EEG markers for the development of translational protocols both within the PharmaCog project and for wider use. [Copyright &y& Elsevier]

Abstract: Objective: The IZOF-based probabilistic approach provides a methodology to study within-individual patterns of a performer''s states. So far, the time course of physiological data before performance have not been investigated within the probabilistic methodology framework. The purpose of this study was to examine the value of the probabilistic approach in the assessment of the time course of physiological indicators of arousal/activation and vigilance during the period preceding the shot, in comparison with the performance-based method. Design: Longitudinal assessment of psycho-physiological data and performance outcomes was conducted on eight elite pistol shooters in a controlled setting. Methods: Each participant performed 60 air-pistol shots in 2 sessions. Skin conductance level and cardiac activity were recorded. Affective states intensity was evaluated on a modified 11-point Borg scale. Affect, HR and SC level were evaluated with a Performance-based approach and a Probabilistic method, and results compared at an individual level. Results: Findings showed the higher effectiveness of the probabilistic method to analyse physiological parameters (skin conductance and heart rate) and to describe the physiological mechanisms associated with shooters’ performance. Conclusions: The probabilistic method better discerned the contribution of arousal/activation and vigilance to optimal and non-optimal performance in elite shooters, thereby providing a sharper representation of the temporal pattern of performers'' states before shooting. From an applied perspective, we believe that the probabilistic approach can help athletes become aware of the subtle variations occurring in their psychophysical states during the preparatory period preceding the shot and not only at the moment of shot release. [Copyright &y& Elsevier]

Abstract: The present electroencephalographic (EEG) study tested the working hypothesis that the amplitude of resting state cortical EEG rhythms (especially alpha, 8–12Hz) was higher in elite athletes compared with amateur athletes and non-athletes, as a reflection of the efficiency of underlying back-ground neural synchronization mechanisms. Eyes closed resting state EEG data were recorded in 16 elite karate athletes, 20 amateur karate athletes, and 25 non-athletes. The EEG rhythms of interest were delta (2–4Hz), theta (4–8Hz), alpha 1 (8–10.5Hz), alpha 2 (10.5–13Hz), beta 1 (13–20Hz), and beta 2 (20–30Hz). EEG cortical sources were estimated by low-resolution brain electromagnetic tomography (LORETA). Statistical results showed that the amplitude of parietal and occipital alpha 1 sources was significantly higher in the elite karate athletes than in the non-athletes and karate amateur athletes. Similar results were observed in parietal and occipital delta sources as well as in occipital theta sources. Finally, a control confirmatory experiment showed that the amplitude of parietal and occipital delta and alpha 1 sources was stronger in 8 elite rhythmic gymnasts compared with 14 non-athletes. These results supported the hypothesis that cortical neural synchronization at the basis of eyes-closed resting state EEG rhythms is enhanced in elite athletes than in control subjects. [Copyright &y& Elsevier]

Abstract: “Neural efficiency” hypothesis posits that neural activity is reduced in experts. Here we tested the hypothesis that compared with non-athletes, elite athletes are characterized by a reduction of cortical activation during an engaging upright standing. EEG (56 channels; Be-plus Eb-Neuro©) and stabilogram (RGM©) data were simultaneously recorded in 10 elite karate, 10 elite fencing athletes, and 12 non-athletes during a simple bipodalic (standard Romberg) and a more engaging monopodalic upright standing. Balance was indexed by body “sway area”. The EEG data were spatially enhanced by surface Laplacian estimation. Cortical activity was indexed by task-related power decrease (TRPD) of EEG alpha power (8–12Hz) during monopodalic referenced to bipodalic condition. The body “sway area” was larger during the monopodalic than bipodalic upright standing in all groups. Low-frequency alpha TRPD (about 8–10Hz) was lower in amplitude in the karate and fencing athletes than in the non-athletes at left central, right central, middle parietal, and right parietal areas (p <0.01). Similarly, the amplitude of high-frequency alpha TRPD (10–12Hz) was lower in the karate and fencing athletes than in the non-athletes at right frontal, left central, right central, and middle parietal areas (p <0.03). These results suggest that during monopodalic referenced to less engaging bipodalic condition, the power decrease (i.e. the desynchronization) of cortical activity at alpha rhythms is largely reduced in elite athletes than in non-athletes, in line with the “neural efficiency” hypothesis. The present study extends our understanding of the physiological mechanisms at the basis of the “neural efficiency” for engaging upright standing in elite athletes. [Copyright &y& Elsevier]

Abstract: The present electroencephalographic (EEG) study evaluated the hypothesis of a preferred directionality of communication flows between brain hemispheres across 24h (i.e., during the whole daytime and nighttime), as an extension of a recent report showing changes in preferred directionality from pre-sleep wake to early sleep stages. Scalp EEGs were recorded in 10 normal volunteers during daytime wakefulness (eyes closed; first period: from 10:00 to 13:00h; second period: from 14:00 to 18:00h; third period: from 19:00 to 22:00h) and nighttime sleep (four NREM-REM cycles). EEG rhythms of interest were delta (1–4Hz), theta (5–7Hz), alpha (8–11Hz), sigma (12–15Hz) and beta (16–28Hz). The direction of the inter-hemispheric information flow was evaluated by computing the directed transfer function (DTF) from these EEG rhythms. Inter-hemispheric directional flows varied as a function of the state of consciousness (wake, NREM sleep, REM sleep) and in relation to different cerebral areas. During the daytime, alpha and beta rhythms conveyed inter-hemispheric signals with preferred Left-to-Right hemisphere direction in parietal and central areas, respectively. During the NREM sleep periods of nighttime, the direction of inter-hemispheric DTF information flows conveyed by central beta rhythms was again preponderant from Left-to-Right hemisphere in the stage 2, independent of cortical areas. No preferred direction emerged across the REM periods. These results support the hypothesis that specific directionality of communication flows between brain hemispheres is associated with wakefulness, NREM (particularly stage 2) and REM states during daytime and nighttime. They also reinforce the suggestive hypothesis of a relationship between inter-hemispheric directionality of EEG functional coupling and frequency of the EEG rhythms. [Copyright &y& Elsevier]

Abstract: Is directionality of electroencephalographic (EEG) synchronization abnormal in amnesic mild cognitive impairment (MCI) and Alzheimer''s disease (AD)? EEG data were recorded in 64 normal elderly (Nold), 69 amnesic MCI, and 73 mild AD subjects at rest condition (closed eyes). Direction of information flux within EEG functional coupling at electrode pairs was performed by directed transfer function (DTF) at delta (2–4Hz), theta (4–8Hz), alpha 1 (8–10Hz), alpha 2 (10–12Hz), beta 1 (13–20Hz), beta 2 (20–30Hz), and gamma (30–40Hz). Parietal to frontal direction of the information flux within EEG functional coupling was stronger in Nold than in MCI and/or AD subjects, namely for alpha and beta rhythms. In contrast, the directional flow within inter-hemispheric EEG functional coupling did not discriminate among the three groups. These results suggest that directionality of parieto-to-frontal EEG synchronization is abnormal not only in AD but also in amnesic MCI. [Copyright &y& Elsevier]

Problem identification Purpose of our research is the development and testing of procedures for the study of functional brain organization in elite athletes and patients with cerebral neurodegenerative processes to test “neural efficiency” hypothesis (i.e. selective cortical activity in experts). Methodology Cortical activity in elite athletes and patients with Alzheimer‘s disease (AD) was indexed by the study of electroencephalographic (EEG) oscillations in the resting state condition and during events. Results ATHLETES ( Del Percio et al., 2008, 2009, 2010; Babiloni et al., 2009, 2010 ). More resting state eyes-closed posterior cortical alpha (8–12 Hz) power was observed in elite athletes than in amateur athletes and non-athletes, thus suggesting that athletes’ brain is more inhibited in this condition. Furthermore, there was a reduced event-related alpha desynchronization as a sign of less cortical activation in elite athletes than in amateur athletes and non-athletes, during both cognitive and motor events, with some exceptions to be better understood. AD PATIENTS ( Babiloni et al., 2004, 2007, 2010, 2013 ). Less resting state eyes-closed posterior cortical alpha (8–10 Hz) power was observed in prodromic and overt AD than in normal elderly subjects, thus suggesting that patients’ brain is less inhibited in this condition. Furthermore, there was a reduced event-related alpha desynchronization as a sign of less cortical activation in the former than in the latter ones during eyes opening. Conclusions “Neural efficiency” as a sign of more selectivity and inhibitory capability of brain oscillatory processes may explain at least in part high cognitive-motor performance in athletes and some cognitive-motor abnormalities in AD patients. Keywords EEG; Cognitive-motor processes; Elite athletes [ABSTRACT FROM AUTHOR]