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The investigation of brain oscillations and connectivity has become an important topic in the recent decade. There are several types of interactions between neuronal oscillations, and one of the most interesting among these interactions is phase-amplitude coupling (PAC). Several methods have been proposed to measure the strength of PAC, including the phase-locking value, circular-linear correlation, and modulation index. In the current study, we compared these traditional PAC methods with simulated electroencephalogram signals. Further, to assess the PAC value at each time point, we also compared two recently established methods, event-related phase-locking value and event-related circular-linear correlation, with our newly proposed event-related modulation index (ERMI). Results indicated that the ERMI has better temporal resolution and is more tolerant to noise than the other two event-related methods, suggesting the advantages of utilizing ERMI in evaluating the strength of PAC within a brain region.

Under the concept of meridian channels that belongs to traditional Chinese medicine, BIOCERAMIC Resonance (BR) has already been applied to many clinical medical research projects with functions mimicking of traditional acupuncture. Forty-five patients were recruited with chronic sleep disorders; 36 patients were given, applied to the device with BIOCERAMIC material and sound rhythm on chest skin surface; 9 patients were included as controls. All study participants completed a sleep pattern and quality of life questionnaire (assessment on psychological and physical causes of sleep disturbances), which was repeated before, during and after treatment. Electroencephalograph (EEG) recordings were analyzed before, during and after treatment. Functional MRI (fMRI) was also used for demonstration of BR effect for another 8 candidates. During the first 3 days of treatment, sleep quality improved in all 36 patients especially to psychological reasons; in 91.7% (33/36) treatment was associated with an elevation in the beta spectrum of the EEG (at 15–27 Hz). The result of fMRI found corresponding cerebral and cerebellar areas of activation and deactivation. BIOCERAMIC Resonance can improve sleep disorder due to psychological causes, with transient alter brain wave activity and functional activation on specific locations of brain., Graphical abstract BIOCERAMIC Resonance is a new technology of using concept of acupuncture from traditional Chinese medicine. No past study is reported for a similar non-invasive and convenience therapy for sleep disturbance. Our study was approach by using questionaire, EEG and fMRI to evaluate the possible effect of BIOCERAMIC Resonance on sleep disturbance and brain physiology.Image 1

There is a growing interest in functional magnetic resonance imaging (fMRI) studies on connectivity networks in the brain when subjects are under exposure to natural sensory stimulation. Because of a complicated coupling between spontaneous and evoked brain activity under real-world stimulation, there is no critical mapping between the experimental inputs and corresponding brain responses. The dataset contains auditory fMRI scans and T1-weighted anatomical scans acquired under eyes-closed and eyes-open conditions. Within each scanning condition, the subject was presented 12 different sound clips, including human voices followed by animal vocalizations. The dataset is meant to be used to assess brain dynamics and connectivity networks under natural sound stimulation; it also allows for empirical investigation of changes in fMRI responses between eyes-closed and eyes-open conditions, between animal vocalizations and human voices, as well as between the 12 different sound clips during auditory stimulation. The dataset is a supplement to the research findings in the paper “Brain dynamics and connectivity networks under natural auditory stimulation” published in NeuroImage. Keywords: fMRI, Connectivity networks, Real-world, Auditory

The analysis of functional magnetic resonance imaging (fMRI) data is challenging when subjects are under exposure to natural sensory stimulation. In this study, a two-stage approach was developed to enable the identification of connectivity networks involved in the processing of information in the brain under natural sensory stimulation. In the first stage, the degree of concordance between the results of inter-subject and intra-subject correlation analyses is assessed statistically. The microstructurally (i.e., cytoarchitectonically) defined brain areas are designated either as concordant in which the results of both correlation analyses are in agreement, or as discordant in which one analysis method shows a higher proportion of supra-threshold voxels than does the other. In the second stage, connectivity networks are identified using the time courses of supra-threshold voxels in brain areas, contingent upon the classifications derived in the first stage. In an empirical study, fMRI data were collected from 40 young adults (19 males, average age 22.76 ± 3.25), who underwent auditory stimulation involving sound clips of human voices and animal vocalizations under two operational conditions (i.e., eyes-closed and eyes-open). The operational conditions were designed to assess confounding effects due to auditory instructions or visual perception. The proposed two-stage analysis demonstrated that stress modulation (affective) and language networks in the limbic and cortical structures were respectively engaged during sound stimulation, and presented considerable variability among subjects. The network involved in regulating visuomotor control was sensitive to the eyes-open instruction, and presented only small variations among subjects. A high degree of concordance was observed between the two analyses in the primary auditory cortex which was highly sensitive to the pitch of sound clips. Our results have indicated that brain areas can be identified as concordant or discordant based on the two correlation analyses. This may further facilitate the search for connectivity networks involved in the processing of information under natural sensory stimulation.

Establishing an appropriate control technique with high accuracy has become the central issue for robotic applications to achieve anthropomorphic functions. The electromyography (EMG) method, which approaches various human motions by adjusting signals in the manipulator control scheme, is especially gaining popularity among assistive robotics. In this study, an EMG-based classification method is incorporated to control an assistive robot arm and perform interaction in human arm movements. The system is implemented based on a support-vector machine (SVM); it classifies motions of upper human limbs according to EMG signals recorded from the brachioradialis, the biceps and the anterior deltoid as the input features. With the proposed method, six categories of human arm movements can be identified, and the classification results can thus be remotely transmitted to control an assistive robot to mimic motions of the human arm. The performance of the proposed classification method was evaluated using 72 segments in 5 second EMG signals from two subject. The overall accuracy rate can reach 94% based on the selected EMG features for each measured muscle. The results suggest the importance of feature selection according to the morphology of EMG waveforms recorded from different muscle bundles. The performance of the proposed method has been quantitatively evaluated, and an assistive robot arm can be remotely controlled using EMG signals with a high accuracy rate.

Brain oscillations and connectivity have emerged as promising measures of evaluating memory processes, including encoding, maintenance, and retrieval, as well as the related executive function. Although many studies have addressed the neural mechanisms underlying working memory, most of these studies have focused on the visual modality. Neurodynamics and functional connectivity related to auditory working memory are yet to be established. In this study, we explored the dynamic of high density (128-channel) electroencephalography (EEG) in a musical delayed match-to-sample task (DMST), in which 36 participants were recruited and were instructed to recognize and distinguish the target melodies from similar distractors. Event-related spectral perturbations (ERSPs), event-related phase-amplitude couplings (ERPACs), and phase-locking values (PLVs) were used to determine the corresponding brain oscillations and connectivity. First, we observed that low-frequency oscillations in the frontal, temporal, and parietal regions were increased during the processing of both target and distracting melodies. Second, the cross-frequency coupling between low-frequency phases and high-frequency amplitudes was elevated in the frontal and parietal regions when the participants were distinguishing between the target from distractor, suggesting that the phase-amplitude coupling could be an indicator of neural mechanisms underlying memory retrieval. Finally, phase-locking, an index evaluating brain functional connectivity, revealed that there was fronto-temporal phase-locking in the theta band and fronto-parietal phase-locking in the alpha band during the recognition of the two stimuli. These findings suggest the existence of functional connectivity and the phase-amplitude coupling in the neocortex during musical memory retrieval, and provide a highly resolved timeline to evaluate brain dynamics. Furthermore, the inter-regional phase-locking and phase-amplitude coupling among the frontal, temporal and parietal regions occurred at the very beginning of musical memory retrieval, which might reflect the precise timing when cognitive resources were involved in the retrieval of targets and the rejection of similar distractors. To the best of our knowledge, this is the first EEG study employing a naturalistic task to study auditory memory processes and functional connectivity during memory retrieval, results of which can shed light on the use of natural stimuli in studies that are closer to the real-life applications of cognitive evaluations, mental treatments, and brain-computer interface.

Cognitive studies have suggested that anxiety is correlated with cognitive performance. Previous research has focused on the relationship between anxiety level and the perceptual load within the frontal region, such as the dorsolateral prefrontal and anterior cingulate cortices. High-anxious individuals are predicted to have worse performance on cognitively-demanding tasks requiring efficient cognitive processing. A few functional magnetic resonance imaging studies have specifically discussed the performance and brain activity involving working memory for high-anxious individuals. This topic has been further explored with electroencephalography, although these studies have mostly provided results involving visual face-related stimuli. In this study, we used auditory stimulation to manipulate the working memory load and attempted to interpret the deficiency of cognitive function in high-anxious participants or patients using functional near infrared spectroscopy (fNIRS). The fNIRS signals of 30 participants were measured while they were performing an auditory working memory task. For the auditory n-back task, there were three experimental conditions, including two n-back task conditions of stimuli memorization with different memory load and a condition of passive listening to the stimuli. Hemodynamic responses from frontal brain regions were recorded using a wireless fNIRS device. Brain activation from the ventrolateral and orbital prefrontal cortex were measured with signals filtered and artifacts removed. The fNIRS signals were then standardized with statistical testing and group analysis was performed. The results revealed that there were significantly stronger hemodynamic responses in the right ventrolateral and orbital prefrontal cortex when subjects were attending to the auditory working memory task with higher load. Furthermore, the right lateralization of the prefrontal cortex was negatively correlated with the level of state anxiety. This study revealed the possibility of incorporating fNIRS signals as an index to evaluate cognitive performance and mood states given its flexibility regarding portable applications compared to other neuroimaging techniques.

Brain correlates of cognitive performance have received considerable attention in the area of augmented cognition. Studies focused on the correlation between brain activations and cognitive load have laid their focus on connections integrated by frontal region. Most of the studies have manipulated visual or verbal cognitive load, though the effect of auditory memory load in cognitive performance is still unknown. In this study, functional near-infrared spectroscopy (fNIRS) of twelve subjects were measured when they were performing a paradigm of auditory working memory task. For the auditory n-back task, there are three experimental conditions, including two n-back task conditions of memorizing the stimuli with different memory load, and a condition of passive listening to the stimuli. The stimuli are sound combinations of major, minor, and dissonant chords. Hemodynamic responses from frontal brain regions were recorded using a wireless fNIRS device. Brain activations from ventrolateral and orbital prefrontal cortex are measured with signals filtered and baseline wandering removed. The fNIRS signals are then standardized with statistical test and group analysis carried out. The results revealed that there are significantly stronger hemodynamic responses in bilateral ventrolateral prefrontal cortex when subjects were attending to the auditory working memory task with high load. This study demonstrated the possibility of incorporating fNIRS as an index to evaluate cognitive performance regarding its benefit on the flexibility for portable applications than other neuroimaging techniques. The performance in cognitive function could therefore be quantitatively measured with the proposed method.

Working memory and cognitive performance have received considerable attention in neuroscience research. Most of the studies have demonstrated their interaction over the prefrontal regions while manipulating visual or verbal working memory load. However, less attention has been directed to the impact of musical or auditory input in cognitive performance. In this study, electroencephalography (EEG) of six subjects were measured when they were performing a paradigm of auditory n-back working memory task. EEGLAB and the standardized low-resolution brain electromagnetic tomography (sLORETA) were utilized to parse the scalp EEG signals into source activity. The results revealed that when subjects were engaged in high versus low memory load, there were significantly stronger delta (1–4 Hz) activity in superior frontal gyrus, theta (4–7 Hz) activity in posterior cingulate cortex, alpha 1 (8–10 Hz) and beta 1 (12–16 Hz) activity in insula, but weaker alpha 2 (10–12 Hz) activity in anterior cingulate cortex. These results demonstrated that auditory working memory accompanied distinct brain network modulation to the visual or verbal task.

An automatic method is presented for detecting myocardial ischemia, which can be considered as the early symptom of acute coronary events. Myocardial ischemia commonly manifests as ST- and T-wave changes on ECG signals. The methods in this study are proposed to detect abnormal ECG beats using knowledge-based features and classification methods. A novel classification method, sparse representation-based classification (SRC), is involved to improve the performance of the existing algorithms. A comparison was made between two classification methods, SRC and support-vector machine (SVM), using rule-based vectors as input feature space. The two methods are proposed with quantitative evaluation to validate their performances. The results of SRC method encompassed with rule-based features demonstrate higher sensitivity than that of SVM. However, the specificity and precision are a trade-off. Moreover, SRC method is less dependent on the selection of rule-based features and can achieve high performance using fewer features. The overall performances of the two methods proposed in this study are better than the previous methods.

A suitable tension is critical to good prognoses of surgical repair of injured tendons or ligaments. The existing transducers have limiting roles in measuring the repair tension of intact tendons or ligaments. This study fabricated a sensor to assist surgeons in measuring tension during repair surgery. A peg-type force transducer made from stainless steel served the advantages of easy application and sterilizability. The electrical signals were stabilized by a bridge circuit coupled with two strain gauges. The performances of the system, which were tested by thin and thick silicon tubes, were linear to the applied forces. The results suggest that this system is reliable for force measurement and is beneficial for optimizing the tension of tendons or ligaments during repair surgeries.

The micro-fluidic systems based on the dielectrophoresis (DEP) phenomenon have become one of the hottest topics recently. By combining sensor and actuator into a system, a miniature traveling wave dielectrophoretic (TWDEP) pump can be widely used in biomedical applications. As often powered by lower voltage, the actuator of such a system must be minimized yet with adequate capability to drive the DEP pump to the required speed. The driving circuit for the actuator described in this study is designed and tested to attain the purpose of driving a TWDEP pump for whole blood samples. For improving the driving capability, four-phase AC fields were designed and the output levels were increased to double the supply voltage. Quantitative comparison between the driving circuit and function generator by velocity measurement was made. The driving circuit works properly for the steady state operation of the pump.

Distraction osteogenesis is a procedure in orthopedics for skeletal lengthening. This operation sometimes causes clinical complications such as paralysis and pain related to the rate and extent of distraction. Therefore, a tension-force monitoring system is mandatory to control optimal lengthening. We developed a portable, low-power consumption system to continuously monitor the distracted tensions during the distraction osteogenesis period on the tibias of four male New Zealand white rabbits. The lengthening rate was 1mm per day at frequencies of once a day in one rabbit, and of three successive steps in the others. The system indicates the distraction measured by force, which is considered to be more physiological in nature rather than by distance. Radiographs were also taken for comparison. The results showed that the system was stable and approximate to being ideal. The measured distract-tension recovered to a steady state faster at the frequency of 1mm a day in three steps, rather than once per day. ...

Background: Event-related potentials (ERPs) are currently utilized to study information processing under the influence of neuropsychiatric disorders and are candidate endophenotypes of schizophrenia. However, the traditional ERP approach discards most oscillatory information in the EEG through grand averaging process. This study tried to focus on ERP component of mismatch negativity (MMN) between control and schizophrenia groups in Taiwan. In addition to traditional (grand average) ERP approach, we also compared the time-frequency analysis results of the mismatch negativity. Methods: MMN values were recorded in 55 schizophrenia patients and 42 controls using an auditory oddball paradigm for the duration of the MMN. Besides the traditional grand average approach, the continuous data files were also used for time-frequency analysis via ERP wavelab. Six parameters were explored: event-related spectral perturbation, WTav, avWT, induced activity, intertrial phase coherence and intertrial linear coherence. Results: Traditional ERP approach discovered that group difference occurred in MMN mean amplitude which was compatible with the previous literature. In time-frequency analysis, schizophrenia subjects have lower intertrial phase coherence than controls. Conclusion: Deficit in preattentive sensory information processing, such as MMN, is prominent in Taiwanese schizophrenia subjects. It may also play a role in the basic integrated neural network activity, which could be further explored by time-frequency approach.

A portable biomedical signal recorder is valuable for the detection of acute symptoms. By the use of an ambulatory recorder, investigators and clinicians have more opportunity to analyze paroxysmal or sudden symptoms from the long-duration recorded signals. We propose a modular recorder that contains a motherboard, modules, and an isolated RS-232 interface. The modules have been modified to measure electrogastrogram (EGG), electrocardiogram (ECG), and electroencephalogram (EEG) signals. The compact motherboard includes a microcontroller with a built-in A/D converter, secure digital (SD) memory card, and the driven-right-leg (DRL) circuit. The power consumption of the proposed recorder is less than 2 mA (6 mW). It can continuously record a lead-II ECG signal with a 10-bit resolution for 3.9 days. As a result, the design is suitable for the purpose of long-term portable recording.

This article introduces a wireless 12-lead electrocardiogram (ECG) recording system to monitor high-risk cardiovascular diseases. The design overcomes the limitation of wireless transmission by analog multiplexing. The proposed technique provides three leads of ECG at a time and requires less than 15 sec to display the total 12 leads ECG signals on a remote computer. This increases the chances to discover certain acute symptoms earlier. In addition, the synchronous display of three-lead ECG allows the clinician to survey the ECG from the same plane of the heart. The system is designed with low power consumption and is capable of long-term monitoring.

A versatile, low cost, low power electrical stimulator for urinary incontinence is described in this paper. The device is compact with a simple user interface. The device enables precise adjustments to the frequency, pulse width, mode (burst or continuous), and amplitude of the output current. It is valuable for experimental and clinical applications. Detailed circuit design, complete specification, and test are described.

This study investigated electroencephalography (EEG) oscillatory activity and phase-synchronization in patients with Asperger's syndrome (AS) during visual recognition of emotional faces. In the experiment, 10 AS adults (2 females, age 19.6 ± 1.96) and 10 IQ-matched controls (3 females, age 24.4 ± 3.24) participated in tasks involving emotionality evaluation of either photograph or line-drawing faces. Emotional faces elicited comparable reaction times and evaluation scores between the two groups. In the photograph task, the AS group had no visible N400 component and lower delta/theta synchronization (350–450 ms post-stimulus onset) in the temporal and occipital–parietal regions, and much weaker phase synchronization between distant scalp regions (200–500 ms post-stimulus onset) compared with the control group. In the line-drawing task, the two groups had the same degree of delta/theta synchronization in the central and occipital–parietal regions and comparable phase synchronization between scalp regions. We conclude by hypothesizing that AS patients might have structural deficits in the amygdala and its related limbic structures, a site critical for recognition of emotional faces beyond conscious awareness, but that they preserve the intact function in the cognitive pathway to keep up comparable behavioral performances with the healthy controls through voluntary control of attention.

In this work, an in vivo animal experiment was conducted to show that the pulsed radiofrequency (PRF) stimulation in relieving pain is effective for trigeminal neuralgia. The experiment also reveals that the 10-V stimulation is more effective than 5-V stimulation. Hence, in order to generate a high PRF voltage in a brain stimulator, a low-Q class-E amplifier is proposed to be a high voltage electrical stimulation (ES) driver by controlling the input duty cycle. The steady states of the circuit waveform are represented in two PDEs' and are numerically solved in math tool to achieve circuit parameters. When the driver was operated under the condition of Q = 1 and D = 0.8, the output peak voltage was measured up to 10 V, which is 3 times of V DD . The conversion efficiency of the PRF driver was measured 90% that measured load from 300Ω to 1.8kΩ. The efficiency of the low-Q operation is found to be better under mismatched load than in high-Q operation.

Background The third and fourth heart sound (S3 and S4) are two abnormal heart sound components which are proved to be indicators of heart failure during diastolic period. The combination of using diastolic heart sounds with the standard ECG as a measurement of ventricular dysfunction may improve the noninvasive diagnosis and early detection of myocardial ischemia. Methods In this paper, an adaptive method based on time-frequency analysis is proposed to detect the presence of S3 and S4. Heart sound signals during diastolic periods were analyzed with Hilbert-Huang Transform (HHT). A discrete plot of maximal instantaneous frequency and its amplitude was generated and clustered. S3 and S4 were recognized by the clustered points, and performance of the method was further enhanced by period definition and iteration tracking. Results Using the proposed method, S3 and S4 could be detected adaptively in a same method. 90.3% of heart sound cycles with S3 were detected using our method, 9.6% were missed, and 9.6% were false positive. 94% of S4 were detected using our method, 5.5% were missed, and 16% were false positive. Conclusions The proposed method is adaptive for detecting low-amplitude and low-frequency S3 and S4 simultaneously compared with previous detection methods, which would be practical in primary care.

Background A mechanical noxious stimulator is useful for studies of pain, both for clinic and basic research. We propose to use a pinch stimulator that can not only generate a quantitative, reproducible noxious pinch but also simultaneously provide a synchronous external trigger signal, which is essential for acquisition of evoked potentials. Methods For ethical considerations, audible and visual aids were incorporated so that pinch force could be regulated within a predetermined level. Reproducibility of the nociceptive responses evoked by this device was validated. The device was constructed with a simple circuit, and the element build-in was delicately selected for the minimum required to produce evoked potentials. Results The magnitude of the force output is linearly proportional to the volts produced by the device (i.e., during the pinch). Increases in force correspond to increases in the number of action potentials induced. Conclusions This device may be useful for studying the mechanisms of nociceptive signal processing in the brain through application of reproducible, noxious pinch stimuli.