C3 Electrodes Research Articles

Food Cue Reactivity and the Brain-Heart Axis During Cognitive Stress Following Clinically Relevant Weight Loss

Successful weight loss maintainers are more vulnerable to stress induced eating. The aim of our study was to determine what effect an attention-demanding cognitive performance task had on brain-heart reactivity to visual food cues in women who maintained clinically relevant weight loss vs. women who had never weight cycled. A clinical weight loss group (CWL, n = 17) and a BMI-matched control group (CTL, n = 23) completed modified Stroop tasks that either included high calorie food pictures (Food Stroop) or excluded food cues (Office Stroop). ECG, breathing rate, and EEG were recorded. CWL participants: The Eating Restraint scores (Three Factor Eating Questionnaire) of the CWL participants correlated negatively with their heart rates recorded during the Food Stroop task (r = 0.62, p < 0.01). There was no such relationship in CTL participants. The P200 latencies in CWL participants evoked by the Stroop color-word cues at the C3 electrode were positively correlated to the log high frequency power in their cardiac spectrograms during the Food Stroop (r = 0.63, p < 0.02). There were no such relationships in the Office Stroop task nor in CTL participants. Combined Groups: Participants' heart rates were significantly lower (p < 0.05) and their RMSSD values and the log Total Power in their cardiac spectrograms were significantly greater during the Food Stroop vs. Office Stroop (p < 0.01, Bonferroni corrected). In conclusion Eating Restraint scores in CWL participants correlated with their Stroop heart rates, while the P200 latencies evoked by the Stroop cues correlated with the log high frequency power in their cardiac spectrograms (marker of cardiac vagal activation) during the Food Stroop task. This provides evidence that even 12 months after successful weight loss maintenance the cardiac ANS reactivity to food cues while completing a cognitive performance test was still different to that in individuals of normal weight who never weight cycled. Across all participants the cardiac ANS reactivity evoked by performing the Stroop task was lowered by food cues suggesting that the dampening effect of food cues on cardiac ANS reactivity may be one of the drivers of ‘stress induced' eating.

Sample entropy and surrogate data analysis for Alzheimer's disease.

Alzheimer's disease (AD) is a neurological degenerative disease, which is mainly char-acterized by the memory loss. As electroencephalogram (EEG) device is relatively cheap, portable and non-invasive, it has been widely used in AD-related studies. We proposed a method to detect the differences between healthy subjects and AD patients, which combines classical sample entropy (Sam-pEn) and surrogate data method. EEGs from 14 AD patients and 20 healthy subjects were analyzed. The results based on the original data showed that the SampEn of AD patients was significantly de-creased (p < 0.01) at electrodes c3, f3, o2 and p4, which confirmed that AD could cause complexity loss. However, using original data could be subject to human judgement, so we generated a series of surrogate data. We found that, there were significant difference of SampEn between the original time series and their surrogate data at c3 and o2 electrodes and the differences between healthy subjects and AD patients can be verified. Our method is capable of distinguishing AD patients from healthy subjects, which is consistent with the concept of physiologic complexity, and providing insights for understanding of AD.

CHARACTERIZATION OF MEMBRANE PVA-ENZYME COATED PVC-KTpClPB AS UREA SENSOR WITH POTENTIOMETRIC METHOD

Membranes with PVA, enzymes, and PVC-KTpClPB contribute as pores on the indicator electrode of potentiometric cells to produce voltage. This study aimed to characterize membranes modified with PVA, enzymes, and PVC-KTpClPB as urea sensors. Membrane modification was done in three variations: membrane A (0.504 g of PVA, 0.504 g of PVC, 1 mg of enzymes, and 0.012 g of KTpCIPB), membrane B (0.035 g of PVA, 0.035 g of PVC, 1 mg of enzymes, and 0.012 g of KTpCIPB), and membrane C (0.035 g of PVA, 0.035 g of PVC, 1 mg of enzymes, and 0.050 g of KTpCIPB). The analysis was performed using UV-Visible to obtain the best membranes, namely membrane A and C. The preparation of electrodes was carried out using membrane A and C with various PVA coatings, such as one coating for membrane electrode A1 and C1, two coatings for membrane electrode A2 and C2, and three coatings for membrane electrode A3 and C3. XRD analysis was performed to obtain the best membrane electrode which was the membrane electrode C2. Based on the measurement analysis of electrode membrane in the potentiometric cells with electrochemical techniques, the sensitivity obtained was 19.069 mV/decade with a confidence level of R2 = 0.9434 in the range of 1.10-5-5.10-4 M and detection limit of 1.10-5M.

Prediction of the response to repetitive transcranial magnetic stimulation by spectral powers of prefrontal regions of brain.

Introduction: Quantitative assessments of the effects induced by repetitive transcranial magnetic stimulation (rTMS) are crucial to develop more efficient and personalized treatments. Objectives: To determine the spectral powers of different subbands of EEG correlated with treatment response to rTMS. Materials and Methods: the spectral powers of different subbands of EEG correlated with treatment response to rTMS. Methods: In an open label study 10 patients with intractable major depression received a ten session 20 Hz rTMS over left dorsolateral prefrontal cortex. The EEGs were recorded in all subjects prior and post intervention using a 19-channel EEG system. Hamilton depression rating scale (HAM-D) was also used to determine treatment response. The rTMS protocol consisted of daily one session of 60 trains (2.5 s, inter-train of 17.5 s) at 120% MT for 5 consecutive days per week and 2 weeks. Absolute and relative powers in all electrodes for delta (0-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), sensorimotor rhythm (SMR)(12-15 Hz), beta (15-20 HZ), and high beta (20-28 Hz) were compared prior and post intervention in the responders. Spectral powers of prefrontal and sensorimotor regions of brain predict response to repetitive transcranial magnetic stimulation Results: In the responders (n=5), absolute powers of alpha in F3, F4, C3, and C4 electrodes, absolute power of theta and alpha sub-bands in C4 electrode significantly changed (P<0.05). In the SMR band, absolute powers in the Fp1, Fp2, F3, F4, F7, FZ, C3, and C4 significantly changed (P<0.05). In beta subband, relative power in C4 and absolute power in Fp1, Fp2, F4, CZ, and C4 significantly changed (P < 0.05). Conclusion: The spectral powers of particular sub-bands in prefrontal cortex and sensorimotor areas can predict response to rTMS treatment.

Decoding Voluntary Movement of Single Hand Based on Analysis of Brain Connectivity by Using EEG Signals

Research about decoding neurophysiological signals mainly aims to elucidate the details of human motion control from the perspective of neural activity. We performed brain connectivity analysis with EEG to propose a brain functional network (BFN) and used a feature extraction algorithm for decoding the voluntary hand movement of a subject. By analyzing the characteristic parameters obtained from the BFN, we extracted the most important electrode nodes and frequencies for identifying the direction of movement of a hand. The results demonstrated that the most sensitive EEG components were for frequencies delta, theta, and gamma1 from electrodes F4, F8, C3, Cz, C4, CP4, T3, and T4. Finally, we proposed a model for decoding voluntary movement of the right hand by using a hierarchical linear model (HLM). Through a voluntary hand movement experiment in a spiral trajectory, the Poisson coefficient between the measurement trajectory and the decoding trajectory was used as a test standard to compare the HLM with the traditional multiple linear regression model. It was found that the decoding model based on the HLM obtained superior results. This paper contributes a feature extraction method based on brain connectivity analysis that can mine more comprehensive feature information related to a specific mental state of a subject. The decoding model based on the HLM possesses a strong structure for data manipulation that facilitates precise decoding.

Electroencephalographic Correlates of Continuous Postural Tasks of Increasing Difficulty

Cortical involvement in postural control is well recognized, however the role of non-visual afferents remains unclear. Parietal cortical areas are strongly implicated in vestibulo-spatial functions, but topographical localization during balance tasks remains limited. Here, we use electroencephalography (EEG) during continuous balance tasks of increasing difficulty at single electrode positions. Twenty-four healthy, right-handed individuals performed four balance tasks of increasing difficulty (bipedal and unipedal) and a seated control condition with eyes closed. Subjective ratings of task difficulty were obtained. EEG was recorded from 32 electrodes; 5 overlying sensory and motor regions of interest (ROIs) were chosen for further investigation: C3, Cz, C4, P3, P4. Spectral power and coherence during balance tasks were analyzed in theta (4–8 Hz) and alpha (8–12 Hz) bands. Alpha power reduced as task difficulty increased and this reduction correlated with subjective difficulty ratings. Alpha coherence increased with task difficulty between C3–Cz–C4 electrode pairs. Differential changes in power were observed in Cz, suggestive of a distinct role at this electrode location, which captures lower limb cortical representation. Hemispheric asymmetry was observed, as reflected by greater reductions in theta and alpha power in right-sided areas. Our results demonstrate the functional importance of bilateral central and parietal cortices in continuous balance control. The hemispheric asymmetry observed implies that the non-dominant hemisphere is involved with online monitoring of postural control. Although the posterior parietal asymmetry found may relate to vestibular, somatosensory or multisensory feedback processing, we argue that the finding relates to active balance control rather than simple sensory-intake or reflex circuit activation.

Empathic Cognitions Affected by Undetectable Social Chemosignals: An EEG Study on Visually Evoked Empathy for Pain in an Auditory and Chemosensory Context.

Reduction of mu activity within the EEG is an indicator of cognitive empathy and can be generated in response to visual depictions of others in pain. The current study tested whether this brain response can be modulated by an auditory and a chemosensory context. Participants observed pictures of painful and non-painful actions while pain associated and neutral exclamations were presented (Study 1, N = 30) or while chemosensory stimuli were presented via a constant flow olfactometer (Study 2, N = 22). Chemosensory stimuli were sampled on cotton pads while donors participated in a simulated job interview (stress condition) or cycled on a stationary bike (sport condition). Pure cotton was used as a control. The social chemosignals could not be detected as odors. Activity within the 8–13 Hz band at electrodes C3, C4 (mu activity) and electrodes O1, O2 (alpha-activity) was calculated using Fast-Fourier-Transformation (FFT). As expected, suppression of power in the 8–13 Hz band was stronger when painful as compared to non-painful actions were observed (Study 1, p = 0.020; Study 2, p = 0.005). In addition, as compared to the neutral auditory and chemosensory context, painful exclamations (Study 1, p = 0.039) and chemosensory stress signals (Study 2, p = 0.014) augmented mu-/alpha suppression also in response to non-painful pictures. The studies show that processing of social threat-related information is not dominated by visual information. Rather, cognitive appraisal related to empathy can be affected by painful exclamations and subthreshold chemosensory social information.

EEG-controlled functional electrical stimulation for hand opening and closing in chronic complete cervical spinal cord injury

Background. There are over 33 000 people in the US living with complete tetraplegia due to spinal cord injury (SCI). People with complete tetraplegia rank restoration of hand and arm function as their highest priority, as it would offer greater independence and improved quality of life. In this study, we show that subjects with chronic (>1-year post-injury) C5 or C6 level, motor-complete SCI are able to control a brain computer interface-functional electrical stimulation (BCI-FES) system to enable hand opening and closing. Methods: 8 subjects with C5 or C6 motor-level SCI and 6 uninjured, control subjects participated in 6 sessions of BCI-FES sessions. Electroencephalographic (EEG) signals were acquired using a wireless EEG system and subjects were asked to ‘imagine moving their right hand’ for motor imagery. Average power was extracted in 5 Hz bins (6–35 Hz) from C3, C1, Cz, C2, and C4 electrodes and input as features to a support vector machine classification algorithm. When ‘movement intention’ was classified correctly from the motor imagery period, a custom-designed stimulation sequence was delivered to the forearm muscles via surface electrodes to enable opening and closing of the hand. Results: Average online decoding accuracy during the closed-loop BCI-FES sessions was similar for the SCI (74.8% ± 17.76) and the control (75.5% ± 11.94) group. Online decoding accuracies were validated using Monte Carlo simulations that used 30%, 50%, and 70% training data to validate the decoded online accuracy and Wilcoxon rank sum test found no significant differences between the SCI and Control subjects. Conclusions: This study demonstrates that subjects with motor complete, cervical SCI were able to control a BCI-FES system with decoding accuracies similar to healthy controls after minimal BCI-training. Non-invasive BCI-FES systems may have the potential to restore hand function in people with motor-complete SCI to improve their quality of life.

P90. Super selective amytal injection (Wada-Test) in a 14 year old with left sided parieto-insular epilepsy due to Focal cortical dysplasia

Introduction The classical Wada-test is performed by injecting a narcotic (usually amobarbital) into the left internal carotid artery (ICA) in order to establish language dominance. In the presurgical workup of epilepsy, it has largely been replaced by less invasive methods such as functional MRI and functional Transcranial Doppler Ultrasound. In exceptional cases, the Wada-test can be performed superselectively: the narcotic is injected into a branch of the middle cerebral artery (MCA). This allows proving or excluding language function in a small brain volume. We document the utility of a superselective Wada test in a 14-year-old girl with a dysplastic lesion in the left supramarginal cortex and dorsal insula. Methods A 14 year old girl presented with pharmacoresistant epilepsy. 3 T MRI revealed a left dorsal insular/supramaginal gyrus FLAIR hyperintensity suspicious of focal cortical dysplasia as the likely epileptogenic lesion. Multimodal presurgical work-up confirmed this. Yet, it was questionable if an extended lesionectomy would harm language function. Left ACI Wada-Test was inconclusive. Therefore, a superselective Wada-Test of an M3 branch of the left MCA/perirolandic artery was performed. Results Following the application of 70 mg Amobarbital, both EEG-slowing in electrodes C3, P3, and T5 and repeat angiography confirmed the correct localization of barbiturate action. During the superselective Wada-test, the patient was able to complete a comprehensive test battery of language functions (counting, naming, reading, calculating, spontaneous speech) without evident dysfunction. Neuronavigation and intraoperative electrophysiological monitoring supported an extended lesionectomy, preserving the white matter adjacent to the pyramidal tract. Early after surgery, the patient suffered from a Gerstmann’s syndrome and slight amnestic aphasia. However, this resolved within the first postoperative weeks. Histopathology confirmed focal cortical dysplasia type IIb. Following surgery, the patient is now seizure free for 18 months under reduced antiepileptic drugs. Her academic performance has improved compared to the preoperative status. Conclusion The Wada-test simulates the effect of resective or disconnective surgery on language functions by temporarily inactivating brain areas. Technical advances in catheter angiography allow injecting the narcotic into single MCA-branches or other arteries of similar diameter, thus simulating the effect of small cortical resections. In selected patients, this method can be a valuable supplement of multimodal presurgical workup, and may obviate the need for intra- or extraoperative cortical mapping.

EEG Neural Correlates of Self-Paced Left- and Right-Hand Movement Intention during a Reaching Task.

The study of neural correlates of self-paced movement intention helps develop a more natural and practical brain computer interface. In this paper, we studied EEG neural correlates of self-paced left- and right-hand movement intention during a reaching task. A slow decreased movement related cortical potential (MRCP) related to movement intention was found before both the left- and right-hand movements. The temporal start point and decrement of MRCP before the left- and right-hand reaching movements showed differently. Moreover, alpha band power increase/decrease was observed before the onset of both left- and right-hand movements. Alpha band powers increase before both movement conditions in the frontal-central area. In the central area, alpha band powers decrease consistently at electrodes C3, Cz and C4 before the right-hand reaching movement. While alpha band powers increase at electrodes C3 and Cz before the left-hand reaching movement.

T123. Amplitudes of motor evoked potentials are modulated by preceding a band oscillations: A closed-loop EEG-TMS study

Introduction The amplitudes of MEPs in the resting state are considerably variable in each TMS. This variability of MEP amplitudes may reflect the fluctuation of the excitability of the primary motor cortex (M1). The neural substrates of determining MEP amplitudes for each TMS are still under the debate. There have been a few reports that deals with the relationship between MEP amplitudes and EEG oscillations in the offline analysis (e.g. Maki and Ilmoniemi, 2010). However, an attempt to explore the link between M1 and neural oscillations by a closed-loop EEG-MEP system is scarce. We have developed the closed-loop system and examined the relationship between EEG oscillations and MEP amplitudes. Methods Eighteen healthy adults (21–47 y.o, M:F = 15:3) participated in this study. EEGs were recorded at C3 with four surrounding electrodes, referred to the linked earlobe. Then, EEG signals at the C3 electrode were remontaged by source derivation and Fourier analyzed in the online to obtain EEG power of α or β band. The individual peak frequency of each band was determined in each subject before the MEP sessions using EEGs for about one minute in the resting state. When the online EEG power during MEP sessions reached the predefined threshold of high or low EEG power, a TMS pulse was delivered to record MEPs. About 50 MEPs were obtained for each of high/low power conditions. After recording MEPs, the MEP amplitudes of the high EEG power were compared with those of low power. The analyses were conducted for each of α and β band, respectively. Results MEPs were successfully recorded by the closed-loop system using EEG at C3. MEP amplitudes of the high EEG power condition were significantly higher than those of the low power condition in the α band. On the contrary, MEP amplitudes of the closed-loop by the β band were not significantly different between the conditions of high EEG power and that of low power. Conclusion We demonstrated that the high EEG power in α band resulted in higher MEP amplitudes compared with those of the low power by the customized closed-loop EEG-TMS system. Thus, the higher α power at C3 can be indicative of the higher M1 excitability. Event-related desynchronization is often reported that α or β power decreases before the hand movement (Stancak and Pfurtscheller, 1995). However, this experiment was conducted under the resting state. Therefore, the mechanism that modulates M1 excitability may be different from that of the premovement period. The α power around the central region is reported to originate from the primary sensory cortex (S1) while β power from M1 (Salmelin et al., 1995). It is also well known that M1 and S1 are tightly linked and modulate excitability between each other. Therefore, S1 oscillations may play a more important role to determine M1 excitability through M1-S1 connectivity.

T125. Neural oscillatory changes by the co-ordinated multifocal transcranial magnetic burst stimulation in the motor cortex

Abnormal neural oscillation in human brains such as overt synchronous beta oscillation in Parkinson’s disease can be one of the neural pathological signatures. How to desynchronize the abnormal oscillation is an important issue for treating the Parkinson’s disease. Therefore, neurologists tried to adopt multiple external oscillatory stimulation to desynchronize the neuronal oscillation of the target frequency as clinical treatment. The concept has been approved by coordinated reset neuromodulation in the deep brain stimulation setting. However, it’s unclear if similar effect can be made through noninvasive stimulation. The noninvasive Co-Ordinated Multifocal Burst Stimulation (COMBS) method by utilizing multiple transcranial magnetic stimulation is proposed in this study for investigating the neural oscillatory changes in the motor cortex. Five healthy volunteer subjects including four females were recruited. Three independent figure of eight coils surrounded the motor hot-spot of extensor indicis proprius (EIP) muscle in the left primary motor cortex. We conducted 50 Hz bursts composed of three pulses with 80% active motor threshold intensity of EIP. To desynchronize the target frequency around 6 Hz, we set one stimulation cycle as every coil firing once randomly, with total duration last for 172.5 ms. Three cycles composed one stimulation block. Total 65 blocks with 315 ms pause between each block were conducted. We implemented finger rapid alternative movement task, which was consisted of three behavioral states including preparation, movement, and resting state. Each subject performed 40 trials before and after COMBS session. EEG signal were collected through 64 EEG channels Neuroscan amplifier system. EEG signal processing contained (1) power spectrum density analysis on the C3 or FC3 channel corresponding to the motor cortex, (2) comparison of the event-related synchronization (ERS) or desynchronization (ERD) before and after the COMBS protocol. The experiment results showed the increasing frequency power from 5 to 20 Hz in the C3 and FC3 electrodes after the COMBS. However, the target frequency around 6 Hz was not desynchronized after stimulation. Consistent ERD and ERS of both α and β frequency during the task were observed. Whereas after COMBS, both α and β frequency spectrum power increased in all behavioral states, without changing desynchronization or synchronization ratio. This study proposed an innovative Co-Ordinated Multifocal Burst Stimulation (COMBS). Experimental findings revealed that the neural oscillation change in the target frequency cannot be decreased effectively by COMBS on healthy motor cortex, but it can increase the power spectrum in the 5–20 Hz frequency composition. In the future work, we will adopt this paradigm on the Parkinson’s disease patients for understanding the further neural oscillation changes on the motor cortex.

Post-task Effects on EEG Brain Activity Differ for Various Differential Learning and Contextual Interference Protocols.

A large body of research has shown superior learning rates in variable practice compared to repetitive practice. More specifically, this has been demonstrated in the contextual interference (CI) and in the differential learning (DL) approach that are both representatives of variable practice. Behavioral studies have indicate different learning processes in CI and DL. Aim of the present study was to examine immediate post-task effects on electroencephalographic (EEG) brain activation patterns after CI and DL protocols that reveal underlying neural processes at the early stage of motor consolidation. Additionally, we tested two DL protocols (gradual DL, chaotic DL) to examine the effect of different degrees of stochastic fluctuations within the DL approach with a low degree of fluctuations in gradual DL and a high degree of fluctuations in chaotic DL. Twenty-two subjects performed badminton serves according to three variable practice protocols (CI, gradual DL, chaotic DL), and a repetitive learning protocol in a within-subjects design. Spontaneous EEG activity was measured before, and immediately after each 20-min practice session from 19 electrodes. Results showed distinguishable neural processes after CI, DL, and repetitive learning. Increases in EEG theta and alpha power were obtained in somatosensory regions (electrodes P3, P7, Pz, P4, P8) in both DL conditions compared to CI, and repetitive learning. Increases in theta and alpha activity in motor areas (electrodes C3, Cz, C4) were found after chaotic DL compared to gradual DL, and CI. Anterior areas (electrodes F3, F7, Fz, F4, F8) showed increased activity in the beta and gamma bands after CI. Alpha activity was increased in occipital areas (electrodes O1, O2) after repetitive learning. Post-task EEG brain activation patterns suggest that DL stimulates the somatosensory and motor system, and engages more regions of the cortex than repetitive learning due to a tighter stimulation of the motor and somatosensory system during DL practice. CI seems to activate specifically executively controlled processing in anterior brain areas. We discuss the obtained patterns of post-training EEG traces as evidence for different underlying neural processes in CI, DL, and repetitive learning at the early stage of motor learning.

An Electrochemical Sensing Platform for the Detection of Lead Ions Based on Dicarboxyl‐Calix[4]arene

AbstractA simple and highly sensitive electrochemical sensor COOH−C4 derived from dicarboxyl‐calix[4]arene modified on a screen printed gold electrode (Au) was developed for the determination of lead ions in water samples. A 3‐mercaptopropionic acid (MPA) monolayer was used as a template on the gold electrode for the surface modification with dicarboxyl‐calixarene. The modified electrodes were surface‐characterized using Fourier Transform infrared spectroscopy (FTIR). The data obtained proved the confirmation of each stage of the electrode modification. The electrochemical analyses of the COOH−C4 electrode showed an enhanced electrocatalytic activity and higher current towards Pb2+ ions as compared to the bare Au and MPA/Au electrodes. Under optimum conditions, the differential pulse voltammetry response of COOH−C4 displayed a wide linear response ranging from 280–2500 μg/L for Pb2+ with a detection limit of 6.2 μg/L. In addition, the fabricated electrode showed a high selectivity and stability towards the Pb2+ ions in presence of possible interfering species. The present method was successfully applied to determine Pb2+ ions in real samples with satisfactory precision, with a relative standard deviation of 3.12 % and an acceptable recovery of 92 %, which demonstrated the potential application of dicarboxyl‐calix[4]arene modified on electrodes for heavy‐metal sensing.

Evaluation of electroencephalogram signals of the professional pianists during iconic memory and working memory tests using spectral coherence

Today, the neuroscience has growth in many aspects, and the effects of different factors on memory obtained many achievements. Several scientific and experimental studies evaluated effects of music on style and behavior of people; in this study, we evaluated memory between two groups of people, the professional pianists and normal people, through processing their electroencephalogram (EEG) signals using the coherence measure. In this study, EEG signals from 17 subjects during two memory tasks were recorded. After that, these signals were preprocessed, and spectral coherence connectivity measure between pair of electrodes was computed and then compared in the five frequency bands using independent t-test. This statistical analysis for working memory task showed significant differences in the temporal, central, and parietal lobes, especially in P7, P3, Pz, T8, C3, and C4 electrodes. As we know, these differences are related to learned skills and activities, words and sounds perception, and memory. Furthermore, for iconic memory task, significant differences were observed in the right hemisphere of these two groups. From this task, we can say professional pianists are different from normal people in the perception of images and creativity. Results of this study show the effects of music on human brain and memory.

Evaluation of electroencephalogram signals of the professional pianists during iconic memory and working memory tests using spectral coherence

Today, the neuroscience has growth in many aspects, and the effects of different factors on memory obtained many achievements. Several scientifc and experimental studies evaluated effects of music on style and behavior of people; in this study, we evaluated memory between two groups of people, the professional pianists and normal people, through processing their electroencephalogram (EEG) signals using the coherence measure. In this study, EEG signals from 17 subjects during two memory tasks were recorded. After that, these signals were preprocessed, and spectral coherence connectivity measure between pair of electrodes was computed and then compared in the fve frequency bands using independent t ‑test. Results of this statistical analysis for working memory task showed signifcant differences in the temporal, central, and parietal lobes, especially in P7, P3, Pz, T8, C3, and C4 electrodes. As we know, these differences are related to learned skills and activities, words and sounds perception, and memory. Furthermore, for iconic memory task, signifcant differences were observed in the right hemisphere of these two groups. From this task, we can say professional pianists are different from normal people in the perception of images and creativity. Results of this study show the effects of music on human brain and memory.

Giving A Hand To Pilots With Animated Alarms Based On Mirror System Functioning

Controlled Flight Into Terrain (CFIT) accidents are among the most frequent and deadly accidents in aviation (IATA, 2016). Pilots have sometimes only a few seconds to react to the ‘Pull-Up’ alarm that indicates an imminent collision with the ground. The auditory modality of the alarm can generate stress, which can disrupt cognitive processes (Porcelli et al., 2008) and negatively impact the ability to take timely and appropriate actions (Scholz et al., 2009). While in general humans are less sensitive to auditory stimuli than to visual stimuli (Mrugalska et al. 2016), the auditory component of the ‘Pull-Up’ alarm is loud and prominent whereas its visual component is more discreet (i.e., small text). Consequently, a first step to enhance the efficiency of this alarm would be to increase the conspicuity of its visual component by enlarging the ‘Pull-Up’ text size and to increase its salience by displacing it from the artificial horizon to the bottom of the Primary Flight Display (PFD). However, enlarging the inscription may not be sufficient to cope with the loss of cognitive performance due to stress (BEA, 2009). Previous researched found that watching an action activates premotor cortex and pre-initiates the gesture imitation through the mirror neuron system (Ocampo & Kritikos, 2011). Therefore, presenting a video of the gesture to perform (i.e., a hand pulling the sidestick), in case of imminent impact with the ground, should pre-activate the motor reaction to the alarm and then improve the pilots’ performance in terms of reaction time. The present experiment aimed at assessing whether these ‘Pull-Up’ video better performance than more conventional ‘Pull-Up’ alarms. Both behavioral and electroencephalographic (EEG) results were used to assess the best alarm design.

Effects of A 60 Hz Magnetic Field of Up to 50 milliTesla on Human Tremor and EEG: A Pilot Study.

Humans are surrounded by sources of daily exposure to power-frequency (60 Hz in North America) magnetic fields (MFs). Such time-varying MFs induce electric fields and currents in living structures which possibly lead to biological effects. The present pilot study examined possible extremely low frequency (ELF) MF effects on human neuromotor control in general, and physiological postural tremor and electroencephalography (EEG) in particular. Since the EEG cortical mu-rhythm (8–12 Hz) from the primary motor cortex and physiological tremor are related, it was hypothesized that a 60 Hz MF exposure focused on this cortical region could acutely modulate human physiological tremor. Ten healthy volunteers (age: 23.8 ± 4 SD) were fitted with a MRI-compatible EEG cap while exposed to 11 MF conditions (60 Hz, 0 to 50 mTrms, 5 mTrms increments). Simultaneously, physiological tremor (recorded from the contralateral index finger) and EEG (from associated motor and somatosensory brain regions) were measured. Results showed no significant main effect of MF exposure conditions on any of the analyzed physiological tremor characteristics. In terms of EEG, no significant effects of the MF were observed for C1, C3, C5 and CP1 electrodes. However, a significant main effect was found for CP3 and CP5 electrodes, both suggesting a decreased mu-rhythm spectral power with increasing MF flux density. This is however not confirmed by Bonferroni corrected pairwise comparisons. Considering both EEG and tremor findings, no effect of the MF exposure on human motor control was observed. However, MF exposure had a subtle effect on the mu-rhythm amplitude in the brain region involved in tactile perception. Current findings are to be considered with caution due to the small size of this pilot work, but they provide preliminary insights to international agencies establishing guidelines regarding electromagnetic field exposure with new experimental data acquired in humans exposed to high mT-range MFs.

67. Cortical evoked potentials after stimulation of cutaneous nerve fibres by micro-patterned electrodes with different interrail gaps

To demonstrate that selective stimulation of intraepidermal nociceptive free endings can be performed using a micro-patterned comblike electrode with interrail gap of 150 μm. In 5 healthy subjects, we stimulated the skin of the hand dorsum with the micro-patterned electrode and with a similar electrode with interrail distance of 1 mm. Stimulation was performed with bursts of 10 pulses, 0.2 ms width each, period of 1 ms either delivered randomly or with constant rate. Cortical responses were recorded from Cz-Au and C3′/C4′-Fz. Stimulating with 1 mm electrode C3′/C4′ recordings showed N20 and W shaped SEP complex; Cz-Au derivation produced a smaller W complex and later smaller N1-P1 waves. Stimulating with 150 μm electrode C3′/C4′ recordings showed only the N1-P1 complex, while no early or medium-latency responses were visible; the Cz-Au recordings showed the N2-P2 complex. The 1 mm gap electrode stimulated large afferents, responsible of the medium-latency components of SEP W. Such components could not be detected with the 150 μm, indicating that large afferents were not stimulated and only small fibre nociceptive afferents were responsible for the late components. The micro-patterned electrode can be considered selective for nociceptive afferents.

Sensory Feedback Interferes with Mu Rhythm Based Detection of Motor Commands from Electroencephalographic Signals.

Background: Electroencephalogram (EEG)-based brain-computer interfaces (BCI) represent a promising component of restorative motor therapies in individuals with partial paralysis. However, in those patients, sensory functions such as proprioception are at least partly preserved. The aim of this study was to investigate whether afferent feedback interferes with the BCI-based detection of efferent motor commands during execution of movements.Methods: Brain activity of 13 able-bodied subjects (age: 29.1 ± 4.8 years; 11 males) was compared between a motor task (MT) consisting of an isometric, isotonic grip and a somatosensory electrical stimulation (SS) of the fingertips. Modulation of the mu rhythm (8–13 Hz) was investigated to identify changes specifically related to the generation of efferent commands. A linear discriminant analysis (LDA) was used to investigate the activation pattern on a single-trial basis. Classifiers were trained with MT vs. REST (periods without MT/SS) and tested with SS and vice versa to quantify the impact of afferent feedback on the classification results.Results: Few differences in the spatial pattern between MT and SS were found in the modulation of the mu rhythm. All were characterized by event-related desynchronization (ERD) peaks at electrodes C3, C4, and CP3. Execution of the MT was associated with a significantly stronger ERD in the majority of sensorimotor electrodes [C3 (p < 0.01); CP3 (p < 0.05); C4 (p < 0.01)]. Classification accuracy of MT vs. REST was significantly higher than SS vs. REST (77% and 63%; p < 10-8). Classifiers trained on MT vs. REST were able to classify SS trials significantly above chance even though no motor commands were present during SS. Classifiers trained on SS performed better in classifying MT instead of SS.Conclusion: Our results challenge the notion that the modulation of the mu rhythm is a robust phenomenon for detecting efferent commands when afferent feedback is present. Instead, they indicate that the mu ERD caused by the processing of afferent feedback generates ERD patterns in the sensorimotor cortex that are masking the ERD patterns caused by the generation of efferent commands. Thus, processing of afferent feedback represents a considerable source of false positives when the mu rhythm is used for the detection of efferent commands.