Repetitive transcranial magnetic stimulation can improve negative symptoms and/or neurocognitive impairments in the first psychosis episode: A randomized controlled trial

OBJECTIVE

Negative symptoms and neurocognitive impairments in psychosis correlate with their severity. Currently, there is no satisfactory treatment. We aimed to evaluate and compare the effects of repetitive transcranial magnetic stimulation(rTMS) on negative symptoms and neurocognitive impairments in patients in first-episode of psychosis(FEP) in a randomized controlled trial(RCT).

METHOD

This is a single-site RCT of 85 patients with FEP. Patients were randomized to receive a 4-week course of active(n = 45) or sham rTMS(n = 40). Factor analysis was applied to a cross-sectional dataset of 744 FEP patients who completed negative symptom evaluation and neurocognitive battery tests. Two independent dimensions were generated and used for the K-means cluster analysis to produce sub-clusters. rTMS of 1-Hz was delivered to the right orbitofrontal(OFC) cortex.

RESULTS

Two distinct dimensional factors of neurocognitive functions(factor-1) and negative symptoms(factor-2), and three clusters with distinctive features were generated. Significant improvements in factor-1 and factor-2 were observed after 4-weeks of rTMS treatment in both the active and sham rTMS groups. The repeated-measures analysis of variance revealed a significant effect of time×group(F = 5.594, p = 0.021, η2 = 0.073) on factor-2, but no effect of time×group on factor-1. Only improvements in negative symptoms were significantly different between the active and sham rTMS groups(p = 0.028). Patients in cluster-3 characterized by extensive negative symptoms, showed greater improvement in the active rTMS group than in the sham rTMS group.

CONCLUSIONS

The 1-Hz right OFC cortex rTMS is more effective in reducing negative symptoms than neurocognitive impairments. It is especially effective in patients with dominantly negative symptoms in FEP.

Reduced Reward Processing in Schizophrenia: A Comprehensive EEG Event-Related Oscillation Study

It is well known that abnormal reward processing is a characteristic feature of various psychopathologies including schizophrenia (SZ). Reduced reward anticipation has been suggested as a core symptom of SZ. The present study aims to evaluate the event-related oscillations (EROs) delta, theta, alpha, beta, and gamma in patients with SZ during the Monetary Incentive Delay (MID) task, which elicits the neural activity of reward processing. Twenty-one patients with SZ and twenty-two demographically matched healthy controls were included in the study. EROs were compared between groups and correlation analyses were conducted to determine a possible relationship between clinical scores and ERO values. Compared with healthy controls, the SZ group had reduced (1) delta and theta amplitudes in the reward condition (2) total beta and non-incentive cue-related beta amplitudes, and (3) incentive cue-related frontal gamma amplitudes. These reductions can be interpreted as impaired dopaminergic neurotransmission and disrupted cognitive functioning in the reward processing of SZ. In contrast, SZ patients showed higher incentive cue-related theta and occipital gamma amplitudes compared to controls. These increments may reflect negative symptoms in SZ. Moreover, theta amplitudes showed a negative correlation with Calgary Depression Scale for Schizophrenia scores and a positive correlation with attentional impulsivity. This is the first study showing the impairments of SZ patients in EROs from delta to gamma frequency bands compared with healthy controls during reward anticipation. Being the first comprehensive study, our results can be interpreted as providing evidence for disrupted brain dynamics in the reward processing of SZ studied by EROs. It may become possible to help patients' wellness by improving our understanding of reward processing in schizophrenia and developing innovative rehabilitation treatments based on these findings.

Low-frequency repetitive transcranial magnetic stimulation over the right orbitofrontal cortex for patients with first-episode schizophrenia: A randomized, double-blind, sham-controlled trial

Repetitive transcranial magnetic stimulation (rTMS) has been used in the treatment of patients with schizophrenia. The conventional targets of rTMS treatment are the dorsolateral prefrontal cortex (DLPFC) and temporoparietal cortex (TPC). However, the efficacy of these two treatment strategies was quite heterogeneous. Structural and functional abnormalities of the orbitofrontal cortex (OFC) in schizophrenia are closely related to negative symptoms. We sought to determine whether 1 Hz rTMS over the right OFC is effective in treating patients with first-episode schizophrenia. In this study, eighty-nine patients with drug-naïve, first-episode schizophrenia were randomly divided into the rTMS (n = 47) or sham stimulation (n = 42) groups, with both groups receiving twenty sessions of 1 Hz rTMS treatment. The PANSS was assessed at baseline, day 10, and day 20, and MATRICS Consensus Cognitive Battery (MCCB) was implemented to assess the cognitive impairment at baseline and day 20. Results showed that patients in the active rTMS group had more improvement in clinical symptoms and cognitive deficits than patients in sham group at day 20. In conclusion, 1 Hz rTMS over OFC can improve psychotic symptoms and cognitive functions in schizophrenic patients. Our study provides a new alternative for the treatment of negative symptoms and cognitive deficits in schizophrenia.

Strategies for enhancing low-frequency performances of triboelectric, electrochemical, piezoelectric, and dielectric elastomer energy harvesting: recent progress and challenges

Mechanical energy harvesting transforms various forms of mechanical energy, including ocean waves, wind, and human motions, into electrical energy, providing a viable solution to address the depletion of fossil fuels and environmental problems. However, one major obstacle for the direct conversion of mechanical energy into electricity is the low frequency of the majority of mechanical energy sources (≤5 Hz), resulting in low energy conversion efficiency, output power and output current. Over recent years, a numerous innovative technologies have been reported to enable improved energy harvesting utilizing various mechanisms. This review aims to present an in-depth analysis of the research progress in low-frequency energy harvesting technologies that rely on triboelectric, electrochemical, piezoelectric, and dielectric elastomer effects. The discussion commences with an overview of the difficulties associated with low-frequency energy harvesting. The critical aspects that impact the low-frequency performance of mechanical energy harvesters, including working mechanisms, environmental factors, and device compositions, are elucidated, while the advantages and disadvantages of different mechanisms in low-frequency operation are compared and summarized. Moreover, this review expounds on the strategies that can improve the low-frequency energy harvesting performance through the modulations of material compositions, structures, and devices. It also showcases the applications of mechanical energy harvesters in energy harvesting via waves, wind, and human motions. Finally, the recommended choices of mechanical energy harvesters with different mechanisms for various applications are offered, which can assist in the design and fabrication process.

A wavelet-assisted deep learning approach for simulating groundwater levels affected by low-frequency variability

Groundwater level (GWL) simulations allow the generation of reconstructions for exploring the past temporal variability of groundwater resources or provide the means for generating projections under climate change on decadal scales. In this context, analyzing GWLs affected by low-frequency variations is crucial. In this study, we assess the capabilities of three deep learning (DL) models (long short-term memory (LSTM), gated recurrent unit (GRU), and bidirectional LSTM (BiLSTM)) in simulating three types of GWLs affected by varying low-frequency behavior: inertial (dominated by low-frequency), annual (dominated by annual cyclicity) and mixed (in which both annual and low-frequency variations have high amplitude). We also tested if maximal overlap discrete wavelet transform pre-processing (MODWT) of input variables helps to better identify the frequency content most relevant for the models (MODWT-DL models). Only external variables (i.e., precipitation, air temperature as raw data, and effective precipitation (EP)) were used as input. Results indicate that for inertial-type GWLs, MODWT-DL models with raw data were notably more accurate than standalone models. However, DL models performed well for annual-type GWLs, while using EP as input, with MODWT-DL models exhibiting only minor improvements. Using raw data as input improved MODWT-DL models compared to standalone models; nevertheless, all models using EP performed better for annual-type GWLs. For mixed-type GWLs, while using EP as input, MODWT-DL models performed well, with substantial improvements over standalone models. Using raw data as input, improvement of MODWT-DL models is marginal compared to that of standalone models; nevertheless, they perform better than standalone models with EP. The Shapley Additive exPlanations (SHAP) approach used to interpret models highlighted that they preferentially learned from low-frequency in precipitation data to achieve the best simulations for inertial and mixed GWLs. This study showed that MODWT-based input pre-processing is highly suitable to better simulate low-frequency varying GWLs.

Sound Induced Vibrations Deform the Organ of Corti Complex in the Low-Frequency Apical Region of the Gerbil Cochlea for Normal Hearing : Sound Induced Vibrations Deform the Organ of Corti Complex

Human speech primarily contains low frequencies. It is well established that such frequencies maximally excite the cochlea near its apex. But, the micromechanics that precede and are involved in this transduction are not well understood. We measured vibrations from the low-frequency, second turn in intact gerbil cochleae using optical coherence tomography (OCT). The data were used to create spatial maps that detail the sound-evoked motions across the sensory organ of Corti complex (OCC). These maps were remarkably similar across animals and showed little variation with frequency or level. We identify four, anatomically distinct, response regions within the OCC: the basilar membrane (BM), the outer hair cells (OHC), the lateral compartment (lc), and the tectorial membrane (TM). Results provide evidence that active processes in the OHC play an important role in the mechanical interplay between different OCC structures which increases the amplitude and tuning sharpness of the traveling wave. The angle between the OCT beam and the OCC makes that we captured radial motions thought to be the effective stimulus to the mechano-sensitive hair bundles. We found that TM responses were relatively weak, arguing against a role in enhancing mechanical hair bundle deflection. Rather, BM responses were found to closely resemble the frequency selectivity and sensitivity found in auditory nerve fibers (ANF) that innervate the low-frequency cochlea.

Metal-organic framework-derived Co/CoO nanoparticles with tunable particle size for strong low-frequency microwave absorption in the S and C bands

Nowadays, constructing strong absorption materials addressing the low-frequency electromagnetic radiation (S and C bands) from electronic devices remains a significant challenge. In this work, size-tunable Co/CoO nanoparticles (NPs) are fabricated by decomposing zeolitic imidazolate framework (ZIF-67) precursors and subsequent hydrogen reduction. All samples show obvious low-frequency attenuation in the S and C bands. At a thin thickness of 2.3 mm, the minimum reflection loss (RL) value for the Co/CoO NPs of 30 nm reaches up to -90.3 dB at 4.4 GHz, and the corresponding effective absorption bandwidth (EAB) of RL ≤ -10 dB ranges from 3.8 to 5.4 GHz. Notably, 90 % of the electromagnetic waves can be absorbed in the frequency range of 2.3-13.2 GHz, covering almost the entire S, C, and X bands at a thickness of 1.0-4.0 mm. The strong low-frequency absorption performance is attributed to the nano-porous structure, high conduction loss, tunable dielectric/magnetic loss, as well as optimized impedance matching. These Co/CoO NPs are promising candidates for high-efficient microwave absorbers in the low-frequency application.

Low-frequency EPR of ferrimyoglobin fluoride and ferrimyoglobin cyanide: a case study on the applicability of broadband analysis to high-spin hemoproteins and to HALS hemoproteins

An EPR spectrometer has been developed that can be tuned to many frequencies in the range of ca 0.1–15 GHz. Applicability has been tested on ferrimyoglobin fluoride (MbF) and ferrimyoglobin cyanide (MbCN). MbF has a high-spin (S = 5/2) spectrum with ¹⁹F superhyperfine splitting that is only resolved in X-band along the heme normal. Low-frequency EPR also resolves the splitting in the heme plane. Measurement of linewidth as a function of frequency provides the basis for an analysis of inhomogeneous broadening in terms of g-strain, zero-field distribution, unresolved superhyperfine splittings and dipolar interaction. Rhombicity in the g tensor is found to be absent. MbCN (S = 1/2) has a highly anisotropic low spin (HALS) spectrum for which g_x cannot be determined unequivocally in X-band. Low-frequency EPR allows for measurement of the complete spectrum and determination of the g-tensor.

Synergistic inactivation of bacteria based on a combination of low frequency, low-intensity ultrasound and a food grade antioxidant

This study evaluated a synergistic antimicrobial treatment using a combination of low frequency and a low-intensity ultrasound (LFU) and a food-grade antioxidant, propyl gallate (PG), against a model gram-positive (Listeria innocua) and the gram-negative bacteria (Escherichia coli O157:H7). Bacterial inactivation kinetic measurements were complemented by characterization of biophysical changes in liposomes, changes in bacterial membrane permeability, morphological changes in bacterial cells, and intracellular oxidative stress upon treatment with PG, LFU, and a combination of PG + LFU. Combination of PG + LFU significantly (>4 log CFU/mL, P < 0.05) enhanced the inactivation of both L. innocua and E. coli O157:H7 compared to PG or LFU treatment. As expected, L. innocua had a significantly higher resistance to inactivation compared to E. coli using a combination of PG + LFU. Biophysical measurements in liposomes, bacterial permeability measurements, and scanning electron microscope (SEM)-based morphological measurements show rapid interactions of PG with membranes. Upon extended treatment of cells with PG + LFU, a significant increase in membrane damage was observed compared to PG or LFU alone. A lack of change in the intracellular thiol content following the combined treatment and limited effectiveness of exogenously added antioxidants in attenuating the synergistic antimicrobial action demonstrated that oxidative stress was not a leading mechanism responsible for the synergistic inactivation by PG + LFU. Overall, the study illustrates synergistic inactivation of bacteria using a combination of PG + LFU based on enhanced membrane damage and its potential for applications in the food and environmental systems.

Modulation of neuromuscular transmission using transcutaneous direct currents: An exploratory study

OBJECTIVE

To assess the in vivo long-lasting effects on neuromuscular transmission using transcutaneous stimulation with anodal and cathodal direct currents applied over the end-plate region (epDCS).

METHODS

An active DCS electrode was placed over the end-plate region of both abductor pollicis brevis and first dorsal interosseous muscles, with a reference electrode located on the forearm. Cathodal or anodal currents were applied (2.5mA during 15min). Repetitive nerve stimulation of the median and ulnar nerves at the wrist was performed before and after DCS: protocol A - 500 stimuli at 3Hz; protocol B - 30 stimuli at 30Hz. For both muscles, we measured changes in amplitude and area between the first and 4th compound muscle action potential (CMAP) and between the first and 500th CMAP (protocol A); and the change in amplitude and area between the first and 30th CMAP (protocol B).

RESULTS

Anodal current did not change any measurement. Using cathodal epDCS and median nerve testing, there was a larger increase in CMAP amplitude (p=0.046) and a smaller decrease in area (p=0.008) between the first and 30th response (protocol B). Using cathodal epDCS and ulnar nerve testing, there was a possible significant smaller amplitude decrease of the CMAP measured, between the first and fourth response (protocol A).

CONCLUSIONS

Cathodal transcutaneous direct currents over the end-plate may modulate end-plate function by increasing the release of quanta of acetylcholine (Ach) and/or the number of Ach receptors available. Future studies should address this topic.

Enhancement of single-walled carbon nanotube accumulation in glioma cells exposed to low-strength electric field: Promising approach in cancer nanotherapy

The objective of the study is to determine the patterns of regulation of single-walled carbon nanotube accumulation, distribution, and agglomeration in glioma cells exposed to an external electric field. C6 glioma cells were treated with 5 μg/ml DNA wrapped single-walled carbon nanotubes and exposed to bi-phasic electric pulses (6.6 V/m, 200 Hz, pulse duration 1 ms). Nanotube accumulation was determined by Raman microspectroscopy and their intracellular local concentration was evaluated using the G-band intensity in Raman spectra of single-walled carbon nanotubes. It was revealed that the low-frequency and low-strength electric field stimulation of glioma cells exposed to single-walled carbon nanotubes led to facilitation and, thus, to amplification of nanotube accumulation inside the cells. The number of nanotubes in intracellular agglomerates increased from (28.8 ± 13.1) un./agglom. and (84.0 ± 28.7) un./agglom. in control samples to (60.6 ± 21.4) un./agglom. and (184.2 ± 53.4) un./agglom. for 1 h and 2 h stimulation, respectively. Thus, the tumor exposure to an external electric field makes it possible to more effectively regulate the accumulation and distribution of carbon nanotubes inside glioma cells allowing to reduce the applied therapeutic doses of carbon nanomaterial delivered anticancer drugs.

Low-frequency Raman spectrophotometer with wide laser illumination on the sample: A tool for pharmaceutical analytical analysis

This work describes an optical configuration for a Raman spectrophotometer, which permits variation of the laser spot size from 3 to 3000 μm, maintaining a high Raman photons throughput and allowing acquisitions with a short integration time. In addition, the instrument can acquire spectra from the low to middle frequency vibrational range (10 to 2000 cm^-1), on the Stokes and anti-Stokes sides. One of the features of this new optical configuration is the non-use of beam splitters to redirect the scattered light to the detector, which would sacrifice the laser power. The quantitative and qualitative analytical performances of the Raman spectrophotometer were evaluated using chemometric models to predict the concentrations of different active pharmaceutical ingredients (APIs) in mixtures with polymorphs and excipients, as well as by analysis of an API mixture employing hyperspectral imaging. This new optical configuration was shown to be versatile for pharmaceutical purposes and could be used in applications such as the characterization of new drugs or the quality control of raw materials and processes, using normal Raman measurements or SERS (surface-enhanced Raman scattering).

Comparison of high versus low frequency cerebral physiology for cerebrovascular reactivity assessment in traumatic brain injury: a multi-center pilot study

Current accepted cerebrovascular reactivity indices suffer from the need of high frequency data capture and export for post-acquisition processing. The role for minute-by-minute data in cerebrovascular reactivity monitoring remains uncertain. The goal was to explore the statistical time-series relationships between intra-cranial pressure (ICP), mean arterial pressure (MAP) and pressure reactivity index (PRx) using both 10-s and minute data update frequency in TBI. Prospective data from 31 patients from 3 centers with moderate/severe TBI and high-frequency archived physiology were reviewed. Both 10-s by 10-s and minute-by-minute mean values were derived for ICP and MAP for each patient. Similarly, PRx was derived using 30 consecutive 10-s data points, updated every minute. While long-PRx (L-PRx) was derived via similar methodology using minute-by-minute data, with L-PRx derived using various window lengths (5, 10, 20, 30, 40, and 60 min; denoted L-PRx_5, etc.). Time-series autoregressive integrative moving average (ARIMA) and vector autoregressive integrative moving average (VARIMA) models were created to analyze the relationship of these parameters over time. ARIMA modelling, Granger causality testing and VARIMA impulse response function (IRF) plotting demonstrated that similar information is carried in minute mean ICP and MAP data, compared to 10-s mean slow-wave ICP and MAP data. Shorter window L-PRx variants, such as L-PRx_5, appear to have a similar ARIMA structure, have a linear association with PRx and display moderate-to-strong correlations (r ~ 0.700, p < 0.0001 for each patient). Thus, these particular L-PRx variants appear closest in nature to standard PRx. ICP and MAP derived via 10-s or minute based averaging display similar statistical time-series structure and co-variance patterns. PRx and L-PRx based on shorter windows also behave similarly over time. These results imply certain L-PRx variants may carry similar information to PRx in TBI.

Contemporary management of lower extremity venous aneurysms

OBJECTIVE

Lower extremity venous aneurysms may lead to serious morbidity in patients, including pulmonary embolism (PE) and chronic venous insufficiency. Presently, because of the low incidence of these aneurysms, no consensus for their treatment exists. The purpose of this study was to review the presentation and management of lower extremity venous aneurysms at our institution.

METHODS

A retrospective review of all patients with isolated lower extremity venous aneurysms treated at a single tertiary care medical center from 2005 to 2017 was conducted.

RESULTS

Five male and six female patients with lower extremity venous aneurysms were identified, with a mean age of 50.4 years. Three patients presented with deep venous thrombosis or PE, three presented with pain, and five venous aneurysms were found incidentally. Nine of 11 patients had aneurysms involving the popliteal vein; one was in the iliac vein, and one was in the common femoral vein. Diagnosis was made by duplex ultrasound in five patients, magnetic resonance imaging in five patients, and computed tomography venography in one patient. Mean aneurysm to adjacent vein ratio was 2.62. No patients who had venous aneurysms discovered incidentally suffered thromboembolic complications. Three patients who were initially treated conservatively went on to eventual surgical intervention. Six patients underwent surgical intervention. The indication for operation was deep venous thrombosis or PE in three patients and lower extremity swelling in three patients; all were symptomatic at presentation. Three patients had simple venorrhaphy, two patients had aneurysmectomy and ligation of the vein, and one patient underwent aneurysmectomy with placement of an interposition vein graft. Mean follow-up was 26 months, with no recurrent thromboembolism. Perioperative complications included postoperative hematoma (one) and superficial thrombophlebitis (one).

CONCLUSIONS

Lower extremity venous aneurysms continue to represent a rare yet potentially morbid vascular disease. Symptomatic patients demonstrated a clear benefit from surgery vs conservative management. Larger, multicenter studies are required to properly characterize the natural history and management of this disease.

Low-frequency rTMS is better tolerated than high-frequency rTMS in healthy people: Empirical evidence from a single session study

Low-frequency and high-frequency repetitive transcranial magnetic stimulation (rTMS) are similarly efficacious for treatment-resistant depression. Low-frequency is posited to be better tolerated than high-frequency rTMS, however, this is not supported by empirical evidence to date. This study aimed to quantify and compare the tolerability of low-versus high-frequency rTMS. Twenty healthy participants (mean age 38.6 ± 13.9 years) underwent low- and high-frequency rTMS administered on left frontal, fronto-central and central sites at 100% resting motor threshold. For the low-frequency protocol, 60 s of 1 Hz stimulation was applied at each site and for the high-frequency protocol, 3 × 5 s trains of 10 Hz stimulation with a 30 s inter-train interval were applied at each site. Tolerance for each stimulation type was assessed immediately after stimulation through participant ratings of overall intensity of scalp sensations, pain, muscle twitching, discomfort and any other sensation. Low-frequency rTMS was significantly less intense than high-frequency rTMS in overall intensity, pain, muscle twitching (all p < .01) and discomfort (p < .001). Limitations of this study include the healthy participant sample and administration of a single session of rTMS. While further work is needed in clinical samples using typical rTMS treatment protocols, these data provide the first evidence that low-frequency is better tolerated than high-frequency. These findings may inform clinical practice of rTMS treatment for depression (and other illnesses) by supporting the application of low-frequency protocols.

Effects of Non-thermal, Non-cavitational Ultrasound Exposure on Human Diabetic Ulcer Healing and Inflammatory Gene Expression in a Pilot Study

The purpose of this clinical study was to assess, in a limited patient population, the potential for a novel advanced wound care treatment based on low-frequency (20 kHz) low-intensity (spatial peak temporal peak intensity <100 mW/cm²; i.e., pressure amplitude of 55 kPa) ultrasound (LFLI-US), to affect wound closure rate in human diabetic foot ulcers (DFUs) and to effect changes in the relative expression of pro-inflammatory and anti-inflammatory genes. The ratio of expression of these genes, termed the M1/M2 score because it was inspired by the transition of macrophages from pro-inflammatory (M1) to anti-inflammatory (M2) phenotypes as wound healing progresses, was previously presented as a potential healing indicator for DFUs treated with the standard of care. We previously found that non-cavitational, non-thermal LFLI-US delivered with a pulse repetition frequency of 25 Hz was effective at improving wound healing in a pilot study of 20 patients with chronic venous ulcers. In this study, we assessed the potential for weekly LFLI-US exposures to affect wound healing in patients with diabetic ulcers, and we analyzed temporal changes in the M1/M2 score in debrided diabetic wound tissue. Although this was a limited patient population of only 8 patients, wounds treated with LFLI-US exhibited a significantly faster reduction in wound size compared with sham-treated patients (p < 0.001). In addition, the value of the M1/M2 score decreased for all healing diabetic ulcers and increased for all non-healing diabetic ulcers, suggesting that the M1/M2 score could be useful as an indicator of treatment efficacy for advanced DFU treatments. Such an indicator would facilitate clinical decision making, ensuring optimal wound management and thus contributing to reduction of health care expenses. Moreover, the results presented may contribute to an understanding of the mechanisms underlying ultrasonically assisted chronic wound healing. Knowledge of these mechanisms could lead to personalized or patient-tailored treatment.

Electroencephalogram alpha-to-theta ratio over left fronto-temporal region correlates with negative symptoms in schizophrenia

BACKGROUND

Negative symptoms impair outcomes on occupational functioning, social interaction and interpersonal relationships in patients with schizophrenia. Past researchers have reported reduced alpha and increased theta and delta spectral powers on quantitative EEG recordings in those with prominent negative symptoms.

AIM

Present analysis aimed at exploring the relationships between lower-frequency EEG powers and negative symptoms, in schizophrenia, over a period of naturalistic antipsychotic treatment.

METHOD

Fifteen right-handed drug-free/drug-naïve schizophrenia patients (N=15;M=12,F=3) were recruited and assessed on PANSS. Spontaneous 192-channel resting-state EEG was recorded at baseline, and PANSS rating was repeated at 4 weeks. Baseline EEGs of patients were compared to 15 age-sex-handedness matched controls.

RESULTS

Non-significant differences emerged between patient and controls in terms of socio-demographic characteristics. Over left frontal and left temporal regions, baseline ratio of alpha/theta power (bATR) was significantly lower (p<0.001) in patients, correlated negatively with baseline PANSS negative score (PNS) (p<0.05); and over 4-weeks of antipsychotic treatment, left temporal bATR correlated positively with relative improvements in PNS.

CONCLUSION

Reduced alpha power over frontal regions might imply altered arousal and/or impaired attentional process, while abnormal theta range oscillations may relate to impairments in working memory via their influences on theta-gamma coupling. Our findings suggest left-predominant deficiencies in these processes might mediate negative symptoms. Further, since ATR might reflect integrity of certain cognitive processes, those with a higher bATR might possess better cognitive resource at baseline and therefore experience greater improvement in negative symptoms with antipsychotic treatments, at least during the first 4 weeks.

EEG neural correlates of goal-directed movement intention

Using low-frequency time-domain electroencephalographic (EEG) signals we show, for the same type of upper limb movement, that goal-directed movements have different neural correlates than movements without a particular goal. In a reach-and-touch task, we explored the differences in the movement-related cortical potentials (MRCPs) between goal-directed and non-goal-directed movements. We evaluated if the detection of movement intention was influenced by the goal-directedness of the movement. In a single-trial classification procedure we found that classification accuracies are enhanced if there is a goal-directed movement in mind. Furthermore, by using the classifier patterns and estimating the corresponding brain sources, we show the importance of motor areas and the additional involvement of the posterior parietal lobule in the discrimination between goal-directed movements and non-goal-directed movements. We discuss next the potential contribution of our results on goal-directed movements to a more reliable brain-computer interface (BCI) control that facilitates recovery in spinal-cord injured or stroke end-users.

Plate-type elastic metamaterials for low-frequency broadband elastic wave attenuation

In this paper, we numerically and experimentally demonstrate the low-frequency broadband elastic wave attenuation and vibration suppression by using plate-type elastic metamaterial, which is constituted of periodic double-sides stepped resonators deposited on a two-dimensional phononic plate with steel matrix. The dispersion relations, the power transmission spectra, and the displacement fields of the eigenmodes are calculated by using the finite element method. In contrast to the typical phononic plates consisting of periodic stepped resonators deposited on a homogeneous steel plate, the proposed elastic metamaterial can yield large band gap in the low-frequency range, resulting in the low-frequency broadband elastic wave attenuation. The formation mechanisms of the band gap as well as the effects of material and geometrical parameters on the band gap are further explored numerically. Numerical results show that, the formation mechanism of opening the low-frequency band gap is attributed to the coupling between the local resonant Lamb modes of two-dimensional phononic plate and the resonant modes of the stepped resonators. The band gap can be significantly modulated by the material and geometrical parameters. The properties of broadband gaps of the proposed subwavelength scale elastic metamaterials can potentially be applied to vibration and noise reduction in the audio regime as well as broadband elastic wave confinement and modulation in ultrasonic region.

An ultra-broadband low-frequency magnetic resonance system

MR probes commonly employ resonant circuits for efficient RF transmission and low-noise reception. These circuits are narrow-band analog devices that are inflexible for broadband and multi-frequency operation at low Larmor frequencies. We have addressed this issue by developing an ultra-broadband MR probe that operates in the 0.1-3MHz frequency range without using conventional resonant circuits for either transmission or reception. This "non-resonant" approach significantly simplifies the probe circuit and allows robust operation without probe tuning while retaining efficient power transmission and low-noise reception. We also demonstrate the utility of the technique through a variety of NMR and NQR experiments in this frequency range.

Salivary alpha-amylase and cortisol responsiveness following electrical stimulation stress in obsessive-compulsive disorder patients

Salivary α-amylase (sAA) serves as a marker of sympathoadrenal medullary system (SAM) activity. Salivary AA has not been extensively studied in obsessive-compulsive disorder (OCD) patients. In the current study, 45 OCD patients and 75 healthy volunteers were assessed with the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), the Profile of Mood State (POMS), and the State-Trait Anxiety Inventory (STAI). Measures of heart rate variability (HRV), sAA, and salivary cortisol were also obtained following the application of electrical stimulation stress. The Y-BOCS and POMS Tension-Anxiety, Depression-Dejection, Anger-Hostility, Fatigue, and Confusion scores were significantly increased in patients with OCD compared with healthy controls. In contrast, Vigor scores were significantly decreased in patients with OCD relative to scores in healthy controls. There was no difference in HRV between the patients and the controls. Salivary AA levels in female and male OCD patients were significantly elevated relative to controls both before and after electrical stimulation. In contrast, there were no differences in salivary cortisol levels between OCD patients and controls. The elevated secretion of sAA before and after stimulation may suggest an increased responsiveness to novel and uncontrollable situations in patients with OCD. An increase in sAA might be a characteristic change of OCD.