A true response of the brain network during electroacupuncture stimulation at scalp acupoints: An fMRI with simultaneous EAS study.

OBJECTIVES: The aim of this study was to explore simultaneous brain network responses to electroacupuncture stimulation (EAS) at scalp acupoints by accounting for placebo effects. MATERIALS AND METHODS: Sixty healthy subjects were recruited and randomly divided into two groups: Group 1 and Group 2. Functional magnetic resonance imaging (fMRI) was performed in Group 1 with sham acupuncture stimulation at acupoints Shenting (GV24) and Touwei (ST8) without EAS. Group 2 underwent verum EAS at the same acupoints during fMRI. Independent component analysis was used to analyze the fMRI data. Full-factor statistical analysis was used to compare the differences in fMRI data between the two groups and evaluate the changes in functional connectivity in brain networks after verum electrical stimulation (Group 1 [after sham electrical current stimulation - before sham electrical current stimulation] - Group 2 [after verum electrical current stimulation - before verum electrical current stimulation]) (p <.001, extent threshold k = 20 voxels). RESULTS: Six brain networks were identified. Significant increased functional connectivity was observed in the right and left executive control networks, sensorimotor network, and attention network, while decreased functional connectivity was mainly found in the default mode network. There were no statistically significant differences in the salience network. CONCLUSIONS: fMRI with simultaneous EAS provides a method to explore brain network responses due to EAS at scalp acupoints. The networks responsible for cognition are differentially activated by EAS in a coordinated manner.

Neurofeedback of scalp bi-hemispheric EEG sensorimotor rhythm guides hemispheric activation of sensorimotor cortex in the targeted hemisphere.

Oscillatory electroencephalographic (EEG) activity is associated with the excitability of cortical regions. Visual feedback of EEG-oscillations may promote sensorimotor cortical activation, but its spatial specificity is not truly guaranteed due to signal interaction among interhemispheric brain regions. Guiding spatially specific activation is important for facilitating neural rehabilitation processes. Here, we tested whether users could explicitly guide sensorimotor cortical activity to the contralateral or ipsilateral hemisphere using a spatially bivariate EEG-based neurofeedback that monitors bi-hemispheric sensorimotor cortical activities for healthy participants. Two different motor imageries (shoulder and hand MIs) were selected to see how differences in intrinsic corticomuscular projection patterns might influence activity lateralization. We showed sensorimotor cortical activities during shoulder, but not hand MI, can be brought under ipsilateral control with guided EEG-based neurofeedback. These results are compatible with neuroanatomy; shoulder muscles are innervated bihemispherically, whereas hand muscles are mostly innervated contralaterally. We demonstrate the neuroanatomically-inspired approach enables us to investigate potent neural remodeling functions that underlie EEG-based neurofeedback via a BCI.

Herbal preparations for the treatment of hair loss.

Though hair does not serve any crucial physiological function in modern humans, it plays an important role in our self-esteem. Androgenic baldness (androgenic alopecia) and circular/spot baldness (alopecia areata) are the most common forms of hair loss. Many active ingredients of synthetic origin are available for treatment; however, they have a number of limitations. Their effectiveness and safety are questionable and the amount of time needed to achieve the effect is both long and unclear. This has increased interest in finding an alternative approach against hair loss using preparations containing plants and/or their isolated active ingredients. A number of studies (mostly randomized, placebo-controlled) of plants and preparations made of plants have been performed to confirm their effectiveness in treating hair loss. The plants with the most evidence-based effect against alopecia are Curcuma aeruginosa (pink and blue ginger), Serenoa repens (palmetto), Cucurbita pepo (pumpkin), Trifolium pratense (red clover), and Panax ginseng (Chinese red ginseng). The assumed mechanism of action is predominately inhibition of 5α-reductase, with enhanced nutritional support and scalp blood circulation playing a role as well.

Effects of Scalp Acupuncture on Functional Deficits Induced by Early Sensorimotor Restriction.

The aim of this study was to investigate the effects of scalp acupuncture and electrostimulation, combined or not, in a disuse model consisted of early sensorimotor restriction in rats. Male Wistar pups received sensorimotor restriction from the second postnatal day (P2) until P28. Animals were divided into five different groups (n = 6): control (CT), sensorimotor restricted (SR), acupuncture (AC), electrostimulation (EL), and electroacupuncture (AC+EL). Experimental animals received sham, acupuncture, or electrical stimulation, combined or not, of two scalp regions for 7 days (P29-P35). Before treatment period (P29) and after treatment (P36), animals were evaluated with the narrow suspended bar, horizontal ladder, and stride length tests. SR animals had worse performance in the narrow suspended and horizontal ladder tasks compared with SR animals at P29 (p ≤ 0.005). Significant improvements were observed in both tasks in AC, EL, and EL+AC groups comparing P29 and P36 (p < 0.001). Also, at P35, all treated animals performed significantly better motor tasks compared with SR group (p < 0.05). There was no difference between treated groups. Finally, acupuncture and electrical stimulation, combined or not, have beneficial effect on motor performance following early developmental disuse.

Scalp acupuncture treatment for children's autism spectrum disorders: A systematic review and meta-analysis.

BACKGROUND: Autism spectrum disorder (ASD) is a neurodevelopment disorder without definitive cure. Previous studies have provided evidences for efficacy and safety of scalp acupuncture in children with ASD. However, the efficacy of scalp acupuncture treatment (SAT) in children with ASD has not been evaluated systematically. The objective of this study is to evaluate the efficacy of SAT in children with ASD. METHODS: Information from 6 databases, including MEDLINE, EMBASE, Cochrane database, AMED, China National Knowledge Infrastructure, and Wanfang Data, were retrieved from the inception of each database from 1980 through September 2018. Randomized controlled trials evaluating the efficacy of SAT for patients with ASD were included. The primary outcome measures were the Childhood Autism Rating Scale (CARS) and Autism Behavior Checklist (ABC). The secondary outcome measures were Psychoeducational Profile (Third Edition) (PEP-3) scores. Risk of bias assessment and data synthesis were conducted with Review Manager 5.3 software. Methodological quality was assessed with the Cochrane risk of bias tool. RESULTS: Fourteen trials with 968 participants were conducted and 11 of the trials were suitable for meta-analysis. Compared with behavioral and educational interventions, SAT significantly decreased the overall CARS scores for children under 3 years old (mean difference (MD) = 3.08, 95% confidence interval (CI) [-3.96, -2.19], P < .001) and above 3 years old (MD = 5.29, 95% CI [-8.53, -2.06], P < .001), ABC scores (MD = 4.70, 95% CI [-6.94, -2.79], P < .001). Furthermore, SAT significantly improved PEP-3 scores in communication (MD = 3.61, 95% CI [2.85, 4.37], P < .001), physical ability (MD = 2.00, 95% CI [1.16, 2.84], P < .001), and behavior (MD = 2.76, 95% CI [1.80, 2.71], P < .001). CONCLUSION: SAT may be an effective treatment for children with ASD. Given the heterogeneity and number of participants, randomized controlled trials of high quality and design are required before widespread application of this therapy.

A Robust Method with High Time Resolution for Estimating the Cortico-Thalamo-Cortical Loop Strength and the Delay when Using a Scalp Electroencephalography Applied to the Wake-Sleep Transition.

OBJECTIVES: This study aimed to describe a robust method with high time resolution for estimating the cortico-thalamo-cortical (CTC) loop strength and the delay when using a scalp electroencephalography (EEG) and to illustrate its applicability for analyzing the wake-sleep transition. METHODS: The basic framework for the proposed method is the parallel use of a physiological model and a parametric phenomenological model: a neural field theory (NFT) of the corticothalamic system and an autoregressive (AR) model. The AR model is a "stochastic" model that shortens the time taken to extract spectral features and is also a "linear" model that is free from the local-minimum problem. From the relationship between the transfer function of the AR model and the transfer function of the NFT in the low frequency limit, we successfully derived a direct expression of CTC loop strength and the loop delay using AR coefficients. RESULTS: Using this method to analyze sleep-EEG data, we were able to clearly track the wake-to-sleep transition, as the estimated CTC loop strength (c2) decreased to almost zero. We also found that the c2-distribution during nocturnal sleep is clearly bimodal in nature, which can be well approximated by the superposition of two Gaussian distributions that correspond to sleep and wake states, respectively. The estimated loop delay distributed ∼0.08 s, which agrees well with the previously reported value estimated by other methods, confirming the validity of our method. CONCLUSIONS: A robust method with high time resolution was developed for estimating the cortico-thalamo-cortical loop strength and the delay when using a scalp electroencephalography. This method can contribute not only to detecting the wake-sleep transition, but also to further understanding of the transition, where the cortico-thalamo-cortical loop is thought to play an important role.

Effectiveness Evaluation of Real-Time Scalp Signal Separating Algorithm on Near-Infrared Spectroscopy Neurofeedback.

Near-infrared spectroscopy (NIRS), one of the candidates to be used in a neurofeedback system or brain-computer interface (BCI), measures the brain activity by monitoring the changes in cerebral hemoglobin concentration. However, hemodynamic changes in the scalp may affect the NIRS signals. In order to remove the superficial signals when NIRS is used in a neurofeedback system or BCI, real-time processing is necessary. Real-time scalp signal separating (RT-SSS) algorithm, which is capable of separating the scalp-blood signals from NIRS signals obtained in real-time, may thus be applied. To demonstrate its effectiveness, two separate neurofeedback experiments were conducted. In the first experiment, the feedback signal was the raw NIRS signal recorded while in the second experiment, deep signal extracted using RT-SSS algorithm was used as the feedback signal. In both experiments, participants were instructed to control the feedback signal to follow a predefined track. Accuracy scores were calculated based on the differences between the trace controlled by feedback signal and the targeted track. Overall, the second experiment yielded better performance in terms of accuracy scores. These findings proved that RT-SSS algorithm is beneficial for neurofeedback.

Assessing the quality of reports about randomized controlled trials of scalp acupuncture combined with another treatment for stroke.

BACKGROUND: This study was designed to assess the quality of reporting on randomized controlled trials (RCTs) of scalp acupuncture for the treatment of stroke. METHODS: The following 8 databases were systematically investigated from their inception to December 2015: PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, National Institute of Informatics Scholarly and Academic Information Navigator, National Digital Science Library, Korean Traditional Knowledge Portal, and Korean Studies Information Service System. RCTs utilizing scalp acupuncture as an intervention for stroke were selected, and the quality of reports was assessed based on the Consolidated Standards of Reporting Trials 2010 statement (CONSORT) and Standards for Reporting Interventions in Controlled Trials of Acupuncture 2010 (STRICTA). For each study, the overall quality score (OQS) of 13 CONSORT items, a combined key methodological index score (MIS) of 5 CONSORT items, and the OQS of 17 STRICTA items were measured. RESULTS: The original reports of 63 RCTs were ultimately obtained, and the median CONSORT OQS was 7 (minimum 2, maximum 11). Particularly, the items 'trial design', 'sample size', 'ancillary analyses', and 'harms' had a positive rate of less than 10%. The median MIS was 1 (minimum 0, maximum 5), with 'allocation concealment and implementation' and 'intent-to-treat analysis (ITT) analysis' having a positive rate of less than 10%. The median STRICTA OQS was 11 (minimum 6, maximum 14), and only the items 'sample size' and 'intent-to-treat analysis' were reported, with a positive rate of less than 10%. The mean CONSORT OQS increased by approximately 0.81 for each 5-year period in which manuscripts were published (95% confidence interval: 0.43 to 1.19; p < 0.001). No variable was significantly associated with MIS in the ordinal regression model. CONCLUSION: The quality of reports on RCTs investigating scalp acupuncture treatment for stroke was moderate to low. Furthermore, reporting of some items was either insufficient or inadequate in the majority of studies. In order to improve and standardize the quality of RCTs investigating scalp acupuncture for stroke, CONSORT and STRICTA guidelines should be utilized more frequently.

Scalp acupuncture attenuates neurological deficits in a rat model of hemorrhagic stroke.

BACKGROUND: Hemorrhagic stroke accounts for approximately 15% of all stroke cases, and is associated with high morbidity and mortality. Limited human studies suggested that scalp acupuncture could facilitate functional recovery after cerebral hemorrhage. In the current study, we used an animal model of cerebral hemorrhage to examine the potential effects of scalp acupuncture. METHODS: Adult male Sprague-Dawley rats received autologous blood (50µL) into the right caudate nucleus on the right side under pentobarbital anesthesia, and then received scalp acupuncture (DU20 through GB7 on the lesion side) or sham acupuncture (1cm to the right side of the acupoints) (n=10 per group). A group of rats receiving autologous blood into the caudate nucleus but no other intervention, as well as a group of rats receiving anesthesia but no blood injection to the brain (n=10 per group) were included as additional controls. Composite neuroscore, corner turn test, forelimb placing test, wire hang task and beam walking were used to evaluate the behavior of rats. Hematoxylin and Eosin (HE) staining was used to observe the histopathological changes. Western blot was used to detect the content of tumor necrosis factor alpha (TNF-α) and nuclear factor-KappaB (NFκB) protein expression. RESULTS: Scalp acupuncture attenuated neurological deficits (p<0.01 or <0.05 vs. sham acupuncture using a variety of behavioral tests) at 1-7days after the treatment. The brain content of TNF-α and NFκB was decreased (p<0.01 for both). CONCLUSIONS: Scalp acupuncture could improve neurological deficits in a rat model of hemorrhagic stroke.

Repetitive Facial Nerve Stimulation Using Occipitalis Muscle.

PURPOSE: We aimed to evaluate the reliability and reproducibility of repetitive nerve stimulation recorded on occipitalis muscle by comparing recordings on nasalis muscle in healthy subjects. METHODS: A total of 23 healthy subjects (mean age: 44.7 ± 13.8 years) underwent detailed neurological examination and repetitive nerve stimulation using nasalis and occipitalis muscles. Amplitude and area percentage changes of compound muscle action potentials (CMAPs) after repetitive nerve stimulation with different frequency were compared between right and left sides and between recordings on nasalis and occipitalis muscles. RESULTS: Comparisons of percentage amplitude changes of nasalis and occipitalis CMAPs showed no differences (+0.1% ± 3.8% vs. +1.4% ± 3.9%, P = 0.129). Average area percentage change of nasalis CMAPs was 0.3% ± 19.0%, whereas the value of occipitalis CMAP was +2.8% ± 15.2% (P = 0.851). Comparisons of nasalis and occipitalis CMAPs values showed no differences. CONCLUSIONS: The repetitive nerve stimulation recorded on occipitalis muscle is simple, easy to apply, noninvasive, consistent, and reproducible.

Deviance-Related Responses along the Auditory Hierarchy: Combined FFR, MLR and MMN Evidence.

The mismatch negativity (MMN) provides a correlate of automatic auditory discrimination in human auditory cortex that is elicited in response to violation of any acoustic regularity. Recently, deviance-related responses were found at much earlier cortical processing stages as reflected by the middle latency response (MLR) of the auditory evoked potential, and even at the level of the auditory brainstem as reflected by the frequency following response (FFR). However, no study has reported deviance-related responses in the FFR, MLR and long latency response (LLR) concurrently in a single recording protocol. Amplitude-modulated (AM) sounds were presented to healthy human participants in a frequency oddball paradigm to investigate deviance-related responses along the auditory hierarchy in the ranges of FFR, MLR and LLR. AM frequency deviants modulated the FFR, the Na and Nb components of the MLR, and the LLR eliciting the MMN. These findings demonstrate that it is possible to elicit deviance-related responses at three different levels (FFR, MLR and LLR) in one single recording protocol, highlight the involvement of the whole auditory hierarchy in deviance detection and have implications for cognitive and clinical auditory neuroscience. Moreover, the present protocol provides a new research tool into clinical neuroscience so that the functional integrity of the auditory novelty system can now be tested as a whole in a range of clinical populations where the MMN was previously shown to be defective.

Surface Laplacian of scalp electrical signals and independent component analysis resolve EMG contamination of electroencephalogram.

The serious impact of electromyogram (EMG) contamination of electroencephalogram (EEG) is well recognised. The objective of this research is to demonstrate that combining independent component analysis with the surface Laplacian can eliminate EMG contamination of the EEG, and to validate that this processing does not degrade expected neurogenic signals. The method involves sequential application of ICA, using a manual procedure to identify and discard EMG components, followed by the surface Laplacian. The extent of decontamination is quantified by comparing processed EEG with EMG-free data that was recorded during pharmacologically induced neuromuscular paralysis. The combination of the ICA procedure and the surface Laplacian, with a flexible spherical spline, results in a strong suppression of EMG contamination at all scalp sites and frequencies. Furthermore, the ICA and surface Laplacian procedure does not impair the detection of well-known, cerebral responses; alpha activity with eyes-closed; ERP components (N1, P2) in response to an auditory oddball task; and steady state responses to photic and auditory stimulation. Finally, more flexible spherical splines increase the suppression of EMG by the surface Laplacian. We postulate this is due to ICA enabling the removal of local muscle sources of EMG contamination and the Laplacian transform being insensitive to distant (postural) muscle EMG contamination.

The effect of middle age on the late positive component of the auditory event-related potential.

BACKGROUND: We recently described a research study in which age-related changes in interaural asymmetry were elicited using the N400 of the auditory event-related potentials (AERP) (Davis et al, 2013). The N400 was the primary focus due to its sensitivity to various aspects of semantic processing (Kutas and Hillyard, 1984), which we measured using a quasi-dichotic semantic category judgment task in competing speech. In this article, we describe age-related changes that occurred in the late positive component (LPC) of the AERP in the same study. The LPC peak occurs subsequent to the N400 peak on the AERP waveform and has been associated with context updating and further evaluation and processing of stimulus meaning (Juottonen et al, 1996). Neither age group showed significant interaural asymmetry in the LPC. However, a robust age-related difference in LPC scalp topography was observed. PURPOSE: The LPC of the auditory event-related potentials was utilized to evaluate age-related differences in language processing in a quasi-dichotic competing speech task. RESEARCH DESIGN: Electrophysiological responses were obtained on a word-pair semantic categorization task presented through a front loudspeaker while ignoring competing speech that was presented through either left (competition left [CL]) or right (competition right [CR]) loudspeakers. The LPC was compared between young and middle-aged groups in three conditions: side of competition, semantic judgment, and electrode position. STUDY SAMPLE: Twenty young (18-24 yr) and twenty middle-aged (44-57 yr) females with normal hearing sensitivity participated in this study. DATA COLLECTION AND ANALYSIS: Individual, as well as grand-averaged, AERP waveforms and scalp topographies were analyzed in response to the word pairs. The LPC component was subjected to a mixed design analysis of variance (ANOVA) for peak latency and amplitude measures in the latency range of 700-800 msec. Since statistical analyses showed little difference in the LPC component as a function of side of competition, the AERP data were collapsed for the CL and CR conditions. The LPC was analyzed in two ways: first at mid-parieto-central electrode locations, second across midline electrodes from PZ to FZ. RESULTS: Analysis of the mid-parieto-central electrodes showed no amplitude or latency differences for either group or side of competition. The second analysis (across midline electrodes), however, showed a significant amplitude interaction between electrode position and group, indicating that the two age groups were equivalent in the posterior region of the scalp but divergent as electrode site moved frontally. Significant age-related scalp topography differences were found in both semantic judgment conditions. No significant latency differences were found in any condition. CONCLUSIONS: The middle-aged group showed substantially greater LPC peak amplitude in the frontal regions of the scalp than young adults. These results were in concert with N400 results, which suggested that the middle-aged group required more attentional/cognitive resources than young adults in order to maintain a high performance level on a linguistic task in the presence of competing linguistic stimuli (Davis et al, 2013).

Modulation of γ and spindle-range power by slow oscillations in scalp sleep EEG of children.

Deep sleep is characterized by slow waves of electrical activity in the cerebral cortex. They represent alternating down states and up states of, respectively, hyperpolarization with accompanying neuronal silence and depolarization during which neuronal firing resumes. The up states give rise to faster oscillations, notably spindles and gamma activity which appear to be of major importance to the role of sleep in brain function and cognition. Unfortunately, while spindles are easily detectable, gamma oscillations are of very small amplitude. No previous sleep study has succeeded in demonstrating modulations of gamma power along the time course of slow waves in human scalp EEG. As a consequence, progress in our understanding of the functional role of gamma modulation during sleep has been limited to animal studies and exceptional human studies, notably those of intracranial recordings in epileptic patients. Because high synaptic density, which peaks some time before puberty depending on the brain region (Huttenlocher and Dabholkar, 1997), generates oscillations of larger amplitude, we considered that the best chance to demonstrate a modulation of gamma power by slow wave phase in regular scalp sleep EEG would be in school-aged children. Sleep EEG was recorded in 30 healthy children (aged 10.7 ± 0.8 years; mean ± s.d.). Time-frequency analysis was applied to evaluate the time course of spectral power along the development of a slow wave. Moreover, we attempted to modify sleep architecture and sleep characteristics through automated acoustic stimulation coupled to the occurrence of slow waves in one subset of the children. Gamma power increased on the rising slope and positive peak of the slow wave. Gamma and spindle activity is strongly suppressed during the negative peak. There were no differences between the groups who received and did not receive acoustic stimulation in the sleep parameters and slow wave-locked time-frequency analysis. Our findings show, for the first time in scalp EEG in humans, that gamma activity is associated with the up-going slope and peak of the slow wave. We propose that studies in children provide a uniquely feasible opportunity to conduct investigations into the role of gamma during sleep.

Effects of tissue dielectric properties on the electric field induced in tDCS: a sensitivity analysis.

Numerical modeling studies remain the only viable way to accurately predict the electric field (E-field) distribution in transcranial direct current stimulation (tDCS). Despite the existence of multiple studies of this kind, a wide range of different values and properties for the electrical conductivities of the tissues represented is employed. This makes it difficult to predict whether the changes observed between models are due to differences in the geometries of the volume conductors or to the different electrical properties of the tissues. In this study we used the finite element method to calculate the E-field distribution in several spherical head models whose tissues were represented with different isotropic and anisotropic conductivity profiles. Results show that the distribution of the E-field is especially sensitive to the conductivity of the skull, skin and GM. These results might help comparing numerical modeling studies that employ different conductivity values.

[Scalp cooling for chemotherapy-induced alopecia]. / Hoofdhuidkoeling tegen alopecia door chemotherapie.

Alopecia is a very common side effect of cytostatic therapy and is considered one of the most emotionally distressing effects. To prevent alopecia scalp cooling is currently used in some indications in medical oncology in 59 hospitals in the Netherlands. The success of scalp cooling depends on various factors such as type of chemotherapy, dose, infusion time, number of treatment cycles and combinations of drugs. In general, scalp cooling is well tolerated. The reported side-effects are headache, coldness, dizziness and sometimes claustrophobia. An increase in the risk of scalp metastases has not been demonstrated. Proceeding from the South Netherlands Comprehensive Cancer Centre a national working group is put together in order to draw up a national guideline for chemotherapy-induced alopecia.

Interactive rehabilitation and dynamical analysis of scalp EEG.

Electroencephalography (EEG) has been used for decades to measure the brain's electrical activity. Planning and performing a complex movement (e.g., reaching and grasping) requires the coordination of muscles by electrical activity that can be recorded with scalp EEG from relevant regions of the cortex. Prior studies, utilizing motion capture and kinematic measures, have shown that an augmented reality feedback system for rehabilitation of stroke patients can help patients develop new motor plans and perform reaching tasks more accurately. Historically, traditional signal analysis techniques have been utilized to quantify changes in EEG when subjects perform common, simple movements. These techniques have included measures of event-related potentials in the time and frequency domains (e.g., energy and coherence measures). In this study, a more advanced, nonlinear, analysis technique, mutual information (MI), is applied to the EEG to capture the dynamics of functional connections between brain sites. In particular, the cortical activity that results from the planning and execution of novel reach trajectories by normal subjects in an augmented reality system was quantified by using statistically significant MI interactions between brain sites over time. The results show that, during the preparation for as well as the execution of a reach, the functional connectivity of the brain changes in a consistent manner over time, in terms of both the number and strength of cortical connections. A similar analysis of EEG from stroke patients may provide new insights into the functional deficiencies developed in the brain after stroke, and contribute to evaluation, and possibly the design, of novel therapeutic schemes within the framework of rehabilitation and BMI (brain machine interface).

The processing of morphological structure information in Chinese coordinative compounds: an event-related potential study.

The aim of this study was to investigate the morphological structure processing of Chinese compounds at short SOAs of 57ms. Event-related potentials were recorded while 16 Hong Kong Chinese university students were instructed to make visual lexical decisions in a decision-making task involving Chinese compound words. Only words in the category of the coordinative compounding structure were included in the present study. In this compounding structure, both morphemes comprising the compound word are of equal importance, similar to the phrase "in-and-out" in English, where neither "in" nor "out" can be considered the head or modifier in the compound; both morphemes are of equal weight in communicating meaning. While the classic N400 semantic priming effect was replicated at this short SOA, an earlier P250 component, suggested to reflect semantic memory network activation during semantic information processing, was also obtained. The morphological structure effect was only found in the P250 component, suggesting that morphological structure may automatically influence the semantic information processing during Chinese compound word processing.

Probability dependence and functional separation of the object-related and mismatch negativity event-related potential components.

The separation of concurrently presented sounds into distinct auditory objects is accompanied by the elicitation of the object-related negativity (ORN) component of the event-related potential (ERP). In the present study, participants were exposed to tone sequences containing not only concurrent (harmonicity), but also sequential cues (similarity to previous stimuli in the series) for auditory object formation. Although ORN was consistently elicited by two-object relative to one-object sounds, it was modulated by the presentation rate. With increasing probability of sound segregation, ORN amplitude decreased, and its scalp topography shifted from a bilateral towards a unilateral (left-hemispheric) activation pattern. Probability dependence of the ORN matches previous behavioral data. The differential sensitivity of the left- and right-hemispheric response to this manipulation may explain why an ORN probability effect was not obtained in previous electrophysiological studies. The specific functional role of ORN for concurrent sound perception was confirmed by dissociating it from the mismatch negativity (MMN) component as a correlate of processing sequential cues. ORN probability dependence is argued to be functionally relevant for the interaction of concurrent and sequential mechanisms of auditory scene analysis.

The analgesic properties of scalp infiltrations with ropivacaine after intracranial tumoral resection.

BACKGROUND: The issue of postoperative pain after neurosurgery is controversial. It has been reported as mild to moderate and its treatment may be inadequate. Infiltration of the surgical site with local anesthetics has provided transient benefit after craniotomy, but its effect on chronic pain has not been evaluated. Accordingly, we designed the present study to test the hypothesis that ropivacaine infiltration of the scalp reduces acute and persistent postoperative pain after intracranial tumor resection. METHODS: This was a prospective, single-blinded study. Inclusion criteria were intracranial tumor resection, age > or = 18 or < or = 80 yr, and ability to understand and use a visual analog scale (VAS). Exclusion criteria were history of craniotomy, chronic drug abuse, and neurologic disorders. All eligible patients were randomly included in Group I (infiltration) or C (control). Postoperative analgesia was IV acetaminophen combined with nalbuphine. At the end of the surgery, Group I received an infiltration of the surgical site with 20 mL of ropivacaine 0.75%. Acute pain was evaluated hourly by VAS during the first 24 h. The analgesic effect of ropivacaine was evaluated based on total consumption of nalbuphine and VAS scores. The incidence of persistent pain and neuropathic pain was assessed at the 2-mo postoperative evaluation. We used the Student's t-test to compare total nalbuphine consumption, repeated measures analysis of variance with post hoc Bonferroni t-test for VAS score and the Fisher's exact test for chronic and neuropathic pain. RESULTS: Fifty-two patients were enrolled, 25 in Group I and 27 in Group C. Demographic and intraoperative data were similar between groups. Group I showed a nonsignificant trend toward reduced nalbuphine consumption during the first postoperative day, 11.2 +/- 9.2 mg vs 16.6 +/- 11.0 mg for Group C (mean +/- SD, P = 0.054). VAS scores were significantly higher in Group C. Two months after surgery, persistent pain was significantly lower in Group I, 2/24 (8%) vs 14/25 (56%), P = 0.0003. One patient (4.1%) in Group I versus six (25%) patients in Group C (P = 0.04) experienced neuropathic pain. CONCLUSIONS: Because pain is moderate after intracranial tumor resection, there is limited interest in scalp infiltrations with ropivacaine in the acute postoperative period. Nevertheless, these infiltrations may be relevant for the rehabilitation of neurosurgical patients and their quality of life by limiting the development of persistent pain and particularly neuropathic pain.