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In recent years, neuroscientists have been interested to the development of brain-computer interface (BCI) devices. Patients with motor disorders may benefit from BCIs as a means of communication and for the restoration of motor functions. Electroencephalography (EEG) is one of most used for evaluating the neuronal activity. In many computer vision applications, deep neural networks (DNN) show significant advantages. Towards to ultimate usage of DNN, we present here a shallow neural network that uses mainly two convolutional neural network (CNN) layers, with relatively few parameters and fast to learn spectral-temporal features from EEG. We compared this models to three other neural network models with different depths applied to a mental arithmetic task using eye-closed state adapted for patients suffering from motor disorders and a decline in visual functions. Experimental results showed that the shallow CNN model outperformed all the other models and achieved the highest classification accuracy of 90.68%. It's also more robust to deal with cross-subject classification issues: only 3% standard deviation of accuracy instead of 15.6% from conventional method., Updated Figure

Numerous studies have shown that working memory modulates every frequency band's power in the human brain. Yet, the question of how the highly distributed working memory adapts to external demands remains unresolved. Here, we explored frequency band modulations underlying working memory load, taking executive control under account. We hypothesized that synchronizations underlying various cognitive functions may be sequenced in time to avoid interference and that transient modulation of decoding accuracy of task difficulty would vary with increasing difficulty. We recorded whole scalp EEG data from 12 healthy participants, while they performed a visuo-spatial n-back task with three conditions of increasing difficulty, after an initial learning phase. We analyzed evoked spectral perturbations and time-resolved decoding of individual synchronization. Surprisingly, our results provide evidence for persistent decoding above the level-of-chance (83.17% AUC) for combined frequency bands. In fact, the decoding accuracy was higher for the combined than for isolated frequency bands (AUC from 65.93% to 74.30%). However, in line with our hypothesis, frequency band clusters transiently emerged in parieto-occipital regions within two separate time windows for alpha-/beta-band (relative synchronization from approximately 200 to 600 ms) and for the delta-/theta-band (relative desynchronization from approximately 600 to 1000 ms). Overall, these findings highlight concurrent sustained and transient measurable features of working memory load. This could reflect the emergence of stability within and between functional networks of the complex working memory system. In turn, this process allows energy savings to cope with external demands.

Appropriate training burden monitoring is still a challenge for the support staff, athletes, and coaches. Extensive research has been done in recent years that proposes several external and internal indicators. Among all measurements, the importance of cognitive factors has been indicated but has never been really considered in the training monitoring process. While there is strong evidence supporting the use of cognitive demand indicators in cognitive neuroscience, their importance in training monitoring for multiple sports settings must be better emphasized. The aims of this scoping review are to (1) provide an overview of the cognitive demand concept beside the physical demand in training; (2) highlight the current methods for assessing cognitive demand in an applied setting to sports in part through a neuroergonomics approach; (3) show how cognitive demand metrics can be exploited and applied to our better understanding of fatigue, sport injury, overtraining and individual performance capabilities. This review highlights also the potential new ways of brain imaging approaches for monitoring in situ. While assessment of cognitive demand is still in its infancy in sport, it may represent a very fruitful approach if applied with rigorous protocols and deep knowledge of both the neurobehavioral and cognitive aspects. It is time now to consider the cognitive demand to avoid underestimating the total training burden and its management.

National audience; It is well established that hypoxia impairs cognitive function (1). Hypoxia has been recognized as one of the most serious single hazards during flight at altitude. Performance of central executive function as assessed by n-back task is known to be reduced with hypoxia and there is a strong correlation between n-back task performance (i.e. working memory capacity) and reductions in cerebral oxygenation (2). But none of these studies has investigated the physiological variables such as cerebral oxygenation and heart rate (HR) as predictors of altitude-induced decrease cognitive performance.Controlled protocols in a laboratory setting need to be performed first with the concomitant measures of cerebral oxygenation state and HR during standard cognitive tasks before the implementation of a protocol in an ecological situation. The present study aimed to test the association between changes in cerebral oxygenation, HR and cognitive performance during acute normobaric hypoxia exposure at an inspired oxygen fraction (FiO2) of 11.3% (5000m). Additionally, we sought to identify cerebral oxygenation and HR threshold values that are predictive of decreased cognitive performance.

The mechanism of action for the cerebral vasculature hemodynamic response to the electric field effects during transcranial direct current stimulation (tDCS) has been less explored. We postulate that such a mechanistic understanding of the cerebrovascular reactivity (CVR) to tDCS can facilitate adequate tDCS dosing to facilitate cognitive rehabilitation in mild cognitive impairment and dementia as well as motor rehabilitation in stroke and traumatic brain injuries. This study presents a system identification approach to evaluate CVR under high-definition (HD) tDCS using a physiologically constrained model based on a multi-compartmental neurovascular system of vascular smooth muscle, perivascular space, synaptic space, and astrocyte glial cell. The physiologically detailed model generated vessel oscillations in the frequency range of 0.05 – 0.2 Hz driven by nonlinear calcium dynamics. Then, model linearization was performed to develop a grey-box linear model for evaluating the acute effects of HD-tDCS based on the CVR data from healthy humans. CVR was measured using functional near-infrared spectroscopy (fNIRS) with optodes in the vicinity of 4x1 HD-tDCS electrodes. The grey-box linear model response of vessel response through the synaptic potassium pathway was found comparable to known hemodynamic responses. Then, the grey-box linear model was fitted to the CVR to anodal HD-tDCS found from the normalized changes in the fNIRS-total haemoglobin (tHb) concentration (blood volume) in eleven healthy participants. We found that the model pathway from perivascular potassium to the vessel circumference presented the best fNIRS-tHb fit with the least mean square error. The fitted grey-box linear model response presented an initial dip in the vessel response that provided a mechanistic understanding of the fNIRS-tHb changes at the onset of HD-tDCS, which needs to be validated in the future with functional magnetic resonance imaging in conjunction with HD-tDCS.

Background: Partial arterial pressure of carbon dioxide ( C O 2 ) modulates cerebral blood flow through a vasoreactivity mechanism. Near infrared spectroscopy (NIRS) can be used to record these changes in cerebral hemodynamics. However, no laterality comparison of the NIRS signal has been performed despite being a prerequisite for the use of such a method in a vasoreactivity monitoring context. We propose to investigate the NIRS signal laterality in response to a C O 2 -inhalation-based hypercapnia paradigm in healthy volunteers. Methods: Eleven healthy volunteers (6 women, 5 men, mean age: 31 ± 11) underwent a 3-block-design inhalation paradigm: normoxia (5min, “baseline”) – hypercapnia (2min, “stimulation”) – normoxia (5min, “post-stimulation”). NIRS signal was measured using a two-channel oximeter (INVOS 5100C, Medtronic, USA) with sensors placed symmetrically on both left and right sides on each subject’s forehead. Additional heart rate (HR) monitoring was performed simultaneously. Based on the NIRS mean signal pattern, an a priori model of parametric identification was applied for each channel to quantify parameters of interest (amplitude, time delay, excitation and post-stimulation time) for each inhalation block. Results: HR increased significantly during the stimulation block. The quality of the model was satisfactory: mean absolute errors between modelled and experimental signals were lower than the resolution of the device. No significant lateralization was found between left and right values of most of the parameters. Conclusion: Due to the lack of lateralization, this parametric identification of NIRS responses to hypercapnia could bring light to a potential asymmetry and be used as a biomarker in patients with cerebrovascular diseases.

MDS 2019, International Congress of Parkinson's Disease and Movement Disorders, Nice, FRANCE, 22-/09/2019 - 26/09/2019; Background and aims: Evidence suggests that gait in complex situation is influenced by executive function in normal ageing. But to our knowledge, no study revealed what measurement is the most appropriate to assess impaired walking in older adults. The objective is to (1) test the feasibility of our protocol and (2) to explore the cognitive load during a simple vs. dual walking task in younger and older adults. Methods: To date, 6 young adults (mean = 26.7 years old; SD = 4.1) were included in this study. Fifteen young adults and 25 older adults will be included by May 2018. Participants are asked to achieve a walking task including four conditions: (1) normal pace walking, (2) subtracting while standing, (3) walking while subtracting and (4) walking while counting forward. Cognitive load is measured by changes in oxygenated and deoxygenated hemoglobin in dorsolateral prefrontal cortex (fNIRS device) and the NASA-TLX questionnaire completed after each condition. Results: fNIRS analyses are in progress. Preliminary results showed that younger adults felt higher cognitive effort in both conditions 2 and 3 compared to condition 1 (NASAscorescondition2 (mean ± SD): 66 ± 18.7 vs NASAscorecondtion1: 9.5 ± 6.3, W = -2.2, P = 0.03 ; NASAscorecondition3 : 78 ± 14.6 vs NASAscorecondition1, W = -2.2, P = 0.03). No significant differences in speed, cadence and stride length were found between conditions 1, 3 and 4 (p > 0.05). No significant differences in subtraction performances were observed between conditions 2 and 3 (p > 0.05). Conclusions: Higher cognitive load in condition 3 in younger adults confirm that our dual task walking is the most cognitively demanding condition. We expect that our fNIRS results in younger adults will be similar to those observed with NASA-TLX questionnaire. However, discrepancies between those two measures are expected in older adults.

EPIQUE, LYON, FRANCE, 09-/07/2019 - 12/07/2019; La maladie de Parkinson (MP) est la deuxième maladie neurodégénérative la plus fréquente après la maladie d'Alzheimer. Cette maladie entraine des modifications cérébrales (e.g. perte de la substance blanche, volume du cortex antérieur) qui sont associées aux troubles moteurs et cognitifs pouvant apparaître dès les premières années de la maladie. Ceux-ci peuvent avoir des retentissements sur certaines activités de la vie quotidienne, comme la marche, pouvant conduire à un risque de chute important. Les conséquences d'une chute, en termes de vie sociale, de traumatismes psychologiques, de mobilité et de qualité de vie sont majeures. Pour pouvoir prévenir ce risque, il importe de mieux comprendre les facteurs (e.g. cognitifs, neurophysiologiques) les plus prédictifs d'une marche dégradée chez des personnes atteintes de la MP. En particulier, un déficit au niveau des fonctions exécutives peut perturber la marche. Au niveau cérébral, les fonctions exécutives relèvent notamment du cortex préfrontal dorsolatéral (CPFDL). L'objectif de cette recherche préliminaire est d'étudier l'activité cérébrale au niveau du CPFDL pendant la marche chez des personnes atteintes de la maladie de Parkinson par rapport à des personnes âgées, sans troubles neurologiques. A ce jour, 10 personnes atteintes de la maladie de Parkinson et 10 personnes âgées ont participé à cette étude dans laquelle une batterie de tests neuropsychologiques a été proposée pour mesurer les fonctions cognitives des participants. Ils ont également réalisé une tâche de marche comprenant 3 conditions : (1) marche simple (2) soustraction en position debout (3) double tâche (marcher et soustraire en même temps). Lors de ces conditions, les participants étaient équipés de la spectroscopie proche infrarouge fonctionnelle (fNIRS) portable qui mesurait les changements de concentration en hémoglobine oxygénée (?HbO2) pendant la tâche (une augmentation de ?HbO2 signifie une plus forte activité cognitive). Des capteurs enregistraient différents paramètres de marche tels que la vitesse de marche, la cadence et la longueur d'enjambée. Une augmentation de l'activité corticale au niveau du CPFDL est attendue, même dans une tâche de marche seule chez les patients comparativement aux personnes âgées. Les résultats, en cours d'analyse, nous permettront de mieux comprendre les changements au niveau de l'activité corticale pendant la marche et les relations entre l'activité corticale du CPFDL et les performances comportementales (tâches cognitives et tâche de marche) chez des personnes atteintes de la maladie de Parkinson. A terme, ces résultats pourraient être utiles pour identifier au plus tôt des troubles de la marche et proposer une prise en charge de la maladie de Parkinson plus précocement.

Understanding the interactions between brain activity and behavior comprehensively in achieving optimal exercise performance in sports is still lacking. The existent research in this area has been limited by the constraints of sports environments and the robustness of the most suitable non-invasive functional neuroimaging methods (electroencephalography, EEG and functional near-infrared spectroscopy, fNIRS) to motion artifacts and noise. However, recent advances in brain mapping technology should improve the capabilities of the future brain imaging devices to assess and monitor the level of adaptive cognitive-motor performance during exercise in sports environments. The purpose of this position manuscript is to discuss the contributions and issues in behavioral neuroscience related to brain activity measured during exercise and in various sports. A first part aims to give an overview of EEG and fNIRS neuroimaging methods assessing electrophysiological activity and hemodynamic responses of the acute and chronic relation of physical exercise on the human brain. Then, methodological issues, such as the reliability of brain data during physical exertion, key limitations and possible prospects of fNIRS and EEG methods are provided. While the use of such methods in sports environments remains scarce and limited to controlled cycling task, new generation of wearable, whole-scalp EEG and fNIRS technologies could open up a range of new applications in sports sciences for providing neuroimaging-based biomarkers (hemodynamic and/or neural electrical signals) to various types of exercise and innovative training.

Transcranial direct current stimulation (tDCS) is a non-invasive electrical brain stimulation technique that can modulate cortical neuronal excitability and activity. This study utilized functional near infrared spectroscopy (fNIRS) neuroimaging to determine the effects of anodal high-definition (HD)-tDCS on bilateral sensorimotor cortex (SMC) activation. Before (Pre), during (Online), and after (Offline) anodal HD-tDCS (2 mA, 20 min) targeting the left SMC, eight healthy subjects performed a simple finger sequence (SFS) task with their right or left hand in an alternating blocked design (30-s rest and 30-s SFS task, repeated five times). In order to determine the level of bilateral SMC activation during the SFS task, an Oxymon MkIII fNIRS system was used to measure from the left and right SMC, changes in oxygenated (O2Hb) and deoxygenated (HHb) haemoglobin concentration values. The fNIRS data suggests a finding that compared to the Pre condition both the "Online" and "Offline" anodal HD-tDCS conditions induced a significant reduction in bilateral SMC activation (i.e., smaller decrease in HHb) for a similar motor output (i.e., SFS tap rate). These findings could be related to anodal HD-tDCS inducing a greater efficiency of neuronal transmission in the bilateral SMC to perform the same SFS task.

This study investigated whether manipulation of motor cortex excitability by transcranial direct current stimulation (tDCS) modulates neuromuscular fatigue and functional near-infrared spectroscopy (fNIRS)-derived prefrontal cortex (PFC) activation. Fifteen healthy men (27.7 ± 8.4 years) underwent anodal (2 mA, 10 min) and sham (2 mA, first 30 s only) tDCS delivered to the scalp over the right motor cortex. Subjects initially performed a baseline sustained submaximal (30 % maximal voluntary isometric contraction, MVC) isometric contraction task (SSIT) of the left elbow flexors until task failure, which was followed 50 min later by either an anodal or sham treatment condition, then a subsequent posttreatment SSIT. Endurance time (ET), torque integral (TI), and fNIRS-derived contralateral PFC oxygenated (O2Hb) and deoxygenated (HHb) hemoglobin concentration changes were determined at task failure. Results indicated that during the baseline and posttreatment SSIT, there were no significant differences in TI and ET, and increases in fNIRS-derived PFC activation at task failure were observed similarly regardless of the tDCS conditions. This suggests that the PFC neuronal activation to maintain muscle force production was not modulated by anodal tDCS.

To the Editor: We read with interest the recent paper of Tordi et al. ([12][1]) in which it was reported that prior high-intensity cycle exercise caused a speeding of the phase II O2 uptake (V˙o 2) kinetics in a subsequent bout of heavy-intensity cycle exercise. These results are important because

The purpose of this study was to compare O(2) uptake ((.)VO(2)) and muscle electromyography activity kinetics during moderate and severe exercise to test the hypothesis of progressive recruitment of fast-twitch fibers in the explanation of the VO(2) slow component. After an incremental test to exhaustion, 7 trained cyclists (mean +/- SD, 61.4 +/- 4.2 ml x min(-1) x kg(- 1)) performed several square-wave transitions for 6 min at moderate and severe intensities on a bicycle ergometer. The (.)VO(2) response and the electrical activity (i.e., median power frequency, MDF) of the quadriceps vastus lateralis and vastus medialis of both lower limbs were measured continuously during exercise. After 2 to 3 min of exercise onset, MDF values increased similarly during moderate and severe exercise for almost all muscles whereas a (.)VO(2) slow component occurred during severe exercise. There was no relationship between the increase of MDF values and the magnitude of the (.)VO(2) slow component during the severe exercise. These results suggest that the origin of the slow component may not be due to the progressive recruitment of fast-twitch fibers.

Increased levels of triglyceride-rich lipoproteins provoke lipid accumulation in the artery wall, triggering early inflammatory responses central to atherosclerosis like endothelial adhesion molecule expression. The endogenous mechanisms limiting such reactions remain poorly defined. Lipoprotein lipase (LPL) plays a central role in lipid metabolism by hydrolyzing triglyceride rich lipoproteins and releasing fatty acids. We found that LPL treatment reversed tumor necrosis factor α and very low-density lipoprotein (VLDL)-stimulated endothelial vascular cell adhesion molecule 1 (VCAM1) induction and VCAM1 promoter responses, thus recapitulating effects reported with synthetic peroxisome proliferator-activated receptor (PPAR) agonists. In fact, these LPL effects on VCAM1 were absent in endothelial cells isolated from PPARα-deficient mice. This finding suggests a novel antiinflammatory role for LPL. Further studies reveal specificity for PPAR activation through lipolysis in regards to lipoprotein substrate (VLDL ≫ LDL > HDL), PPAR isoform (PPARα ≫ PPARδ > PPARγ), and among fatty acid-releasing lipases. These PPAR responses required intact LPL catalytic activity. In vivo , transgenic mice overexpressing LPL had increased peroxisome proliferation, but not in the genetic absence of PPARα. Although human plasma possesses minimal PPARα activation despite containing abundant free fatty acids, marked PPARα activation is seen with human plasma after LPL is added in vitro or systemically released in vivo . These data suggest a previously uncharacterized pathway in which the key lipolytic enzyme LPL can act on circulating lipoproteins to generate PPARα ligands, providing a potentially important link between lipoprotein metabolism and distal PPARα transcriptional effects.

The origin of the slow component is not fully understood. The mechanical hypothesis is one of the potential factors, because an increase in external mechanical work with fatigue was previously reported for a constant velocity run. The purpose of this study was to determine whether a change in mechanical work could occur during the development of the VO2 slow component under the effect of fatigue.Twelve regional-level competitive runners performed a square-wave transition, corresponding to 95% of the speed associated with peak VO2 obtained during an incremental test. The VO2 response was fit with a classical model including two exponential functions. A specific treadmill with three-dimensional force transducers was used to measure the ground reaction force. Kinetic work (W(kin)), potential work (W(pot)), external work (W(ext)), and an index of internal work (W(int)) per unit of distance were quantified continuously.During the slow component of VO2, a significant increase in W (P0.01), no change in W, and a significant decrease in W and W index (P0.05, P0.001, respectively) were observed.The present study showed that the slow component of VO2 did not result partly from a change in mechanical work under the effect of fatigue. Nevertheless, the decrease in stride frequency (P0.001) and contact time (P0.001) suggested an alternative mechanical explanation. The slow component during running may be due to the cost of generating force or to alterations in the storage and recoil of elastic energy, and not to the external mechanical work.

An exciting and rapidly evolving area in vascular biology and atherosclerosis research over the past 3 years has been the establishment of peroxisome proliferator-activated receptor (PPAR) expression in the vascular and inflammatory cells, and the emerging picture of the roles these ligand-activated nuclear receptor/transcription factors might play in vascular biology and atherosclerosis. Such work is all the more compelling given the ongoing clinical use of PPAR activators in patients. Thiazolidinediones (PPAR-g agonists) are used as insulin sensitizers in diabetic patients known to be at extraordinarily high risk for cardiovascular disease, whereas fibrates (PPAR-a agonists) are used to treat dyslipidemia, particularly in the case of high triglycerides and low high-density lipoprotein cholesterol.