Altered Local Field Potential Relationship Between the Parafascicular Thalamic Nucleus and Dorsal Striatum in Hemiparkinsonian Rats / 神经科学通报·英文版

The thalamostriatal pathway is implicated in Parkinson's disease (PD); however, PD-related changes in the relationship between oscillatory activity in the centromedian-parafascicular complex (CM/Pf, or the Pf in rodents) and the dorsal striatum (DS) remain unclear. Therefore, we simultaneously recorded local field potentials (LFPs) in both the Pf and DS of hemiparkinsonian and control rats during epochs of rest or treadmill walking. The dopamine-lesioned rats showed increased LFP power in the beta band (12 Hz-35 Hz) in the Pf and DS during both epochs, but decreased LFP power in the delta (0.5 Hz-3 Hz) band in the Pf during rest epochs and in the DS during both epochs, compared to control rats. In addition, exaggerated low gamma (35 Hz-70 Hz) oscillations after dopamine loss were restricted to the Pf regardless of the behavioral state. Furthermore, enhanced synchronization of LFP oscillations was found between the Pf and DS after the dopamine lesion. Significant increases occurred in the mean coherence in both theta (3 Hz-7 Hz) and beta bands, and a significant increase was also noted in the phase coherence in the beta band between the Pf and DS during rest epochs. During the treadmill walking epochs, significant increases were found in both the alpha (7 Hz-12 Hz) and beta bands for two coherence measures. Collectively, dramatic changes in the relative LFP power and coherence in the thalamostriatal pathway may underlie the dysfunction of the basal ganglia-thalamocortical network circuits in PD, contributing to some of the motor and non-motor symptoms of the disease.

Música perioperatoria: estado del arte y aplicabilidad en la práctica anestésica / Perioperative music therapy: state of the art and applicability in anesthesia

Introducción: La audición es un proceso complejo en el cual el sonido se convierte en energía eléctrica que se procesa e interpreta a nivel de la corteza auditiva. La musicoterapia es una ciencia de bajo costo aplicable a la anestesiología con beneficios económicos. Como coadyuvante a la terapia farmacológica permite usar menores dosis de algunos medicamentos. Objetivo: revisión no sistemática en bases de datos reconocidas. Metodología: búsqueda exhaustiva sobre revisiones sistemáticas, consensos, metaanálisis, utilizando los descriptores electrónicos en las bases de datos electrónicas: PubMed, Science Direct, OvidSP, EBSCO y SciELO. Arrojó 393 artículos, 80 relacionados con música, musicoterapia, medicina y adulto, 77 con electroencefalografía, estimulación acústica y sincronización cortical, 32 con anestesia balanceada y éteres metílicos, y 68 relacionados con música y anestesiología. Se seleccionaron solo los artículos completos para un total de 100. Se complementó con 2 textos universitarios de física. Conclusión: la música en anestesiología representa una herramienta valiosa como alternativa de tratamiento para disminuir la morbimortalidad y los costos asociados. Se necesitan estudios complementarios para determinar los alcances de ésta asociación.

Audition is a complex process in which sound transduces into electrical energy which is processed and interpreted at the auditory cortex. Music therapy is an inexpensive technique applicable to anesthesia. As an adjuvant to pharmacological interventions it allows reducing the requirements of certain medicines. Objective: a non-systematic review in recognized databases. Methodology: A thorough search of systematic reviews, consensuses and meta-analyses on electronic databases PubMed, Science Direct, OvidSP, EBSCO and SciELO using electronic descriptors. 393 articles were retrieved from the searches which included 80 related with music, music therapy, medicine and adults; 77 regarding electrencephalography, acoustic stimulation and cortical synchronization; 32 on balanced anesthesia and methyl ethers; and, 68 related with music and anesthesia. Only 100 articles were eligible for inclusion as only full text reports were considered. Two university physics textbooks were used as supplemental reading resources. Conclusions: music is a valuable adjuvant of anesthesia which can provide reduced morbidity and mortality and related costs. Further studies are needed to determine the scope of this association.

Multi-channel Synchronization Analysis of Mild Cognitive Impairment in Type 2 Diabetes Patients / 生物医学工程学杂志

The cognitive impairment of type 2 diabetes patients caused by long-term metabolic disorders has been the current focus of attention. In order to find the related electroencephalogram (EEG) characteristics to the mild cognitive impairment (MCI) of diabetes patients, this study analyses the EEG synchronization with the method of multichannel synchronization analysis--S estimator based on phase synchronization. The results showed that the S estimator values in each frequency band of diabetes patients with MCI were almost lower than that of control group. Especially, the S estimator values decreased significantly in the delta and alpha band, which indicated the EEG synchronization decrease. The MoCA scores and S value had a significant positive correlation in alpha band.

On the study methods of electroencephalograph synchronization / 生物医学工程学杂志

Synchronous brain activities are considered as an indicator of the functional binding or integration. In this paper, based on the neural electric activities at various spatial scales, we explained the basic concept and measuring index of neural synchronization; then we summarized the main signal processing methods developed for phase synchronization analysis of electroencephalograph (EEG), including the conventional signal processing method, and modern signal modeling approaches. Finally, the main differences among the different methods were compared and some critical problems in the study of EEG synchronization were discussed.

Research on analytical methods of phase synchronization in EEG / 生物医学工程学杂志

Synchronous brain activities are regarded as the indicator of the functional integration of the brain. Based on the physiological mechanism of synchronous activity, the detection process and research on quantification methods concerning synchronization are explained. Conventional and modern signal processing approaches, such as time analysis, frequency analysis, Hilbert transform (HT), especially wavelet transform (WT), are applied to EEG (electroencephalograph) synchronization study. Simulation data and real data are utilized to test the methods mentioned above, which prove the usefulness and validity of methods. According to the final results, Hilbert analysis is better for its authenticity.

Cortical asymmetry: catching an object in free fall

The main goal of the present study was to analyze theta asymmetry through quantitative electroencephalography (qEEG) when individuals were exposed to a sequential motor task, i.e. catching a ball. The sample was composed of 23 healthy subjects, male and female, between 25 and 40 years of age. A two-way factor Anova was applied to compare pre and post moments related to the balls' drop and scalp regions (i.e., frontal and parieto-occipital cortices). The first analysis of the frontal region compared electrodes in the left, right and left/right hemispheres combined, with the frontal midline electrode (FZ) included in the analysis. The results showed moment and region main effects. The second analysis compared left versus right hemisphere without the FZ site. The findings demonstrated an interaction effect between moment and region. The first parieto-occipital analysis, comparing left, right and central regions, with PZ included in all regions, showed main effects of moment and region. The second analysis, comparing left, right (without Pz) and central regions strictly demonstrated a region main effect. Thus, we observed an asymmetric pattern in the frontal cortex (i.e., planning and response selection) when the subjects were waiting for the balls' drop. Moreover, the left hemisphere seems to engage differently from the other regions when the central nervous system needs to prepare for a motor action. On the other hand, the parieto-occipital cortex, which is related to attentive processes, demonstrated a more asymmetric activity towards the right region which implies a participation of this area in cognitive strategies in this particular task. Taken together, we concluded that the adopted experimental approach can be useful to explore several others directions combining sensorimotor integration tasks with different pathologies, such as depression, Alzheimer's and Parkinson's diseases.

O objetivo do presente experimento foi avaliar medidas de assimetria na banda teta através da electroencefalografia quantitativa (EEGq) durante a realização da atividade motora de apreensão de uma bola em queda livre. A amostra constituiu-se de 23 sujeitos saudáveis de ambos os sexos, faixa etária entre 25 e 40 anos. Anova two-way foi utilizada para comparar os momentos pré e pós relacionados à queda da bola, e às regiões do escalpo (córtex frontal e parieto-occipital). A primeira análise da região frontal comparou eletrodos nos hemisférios esquerdo, direito e esquerdo/direito combinados, incluindo na análise o eletrodo frontal mediano (FZ). O resultado demonstrou um efeito principal para momento e região. A segunda análise comparou os hemisférios direito e esquerdo, sem o eletrodo FZ. Neste achado verificou-se um efeito principal para a interação entre os fatores momento e região. A primeira análise realizada na região parieto-occipital comparou as regiões esquerda, direita e central, com PZ incluídos em todas as áreas, demonstrou efeito principal para momento e região. A segunda análise comparou as regiões esquerda, direita (sem PZ) e central, e verificou-se um efeito principal para região. Tais achados indicaram um padrão de assimetria no córtex frontal (ex., planejamento e seleção de resposta) no momento em que os sujeitos esperavam a queda da bola. Além disso, o hemisfério esquerdo parece engajar-se diferentemente em relação às outras regiões quando o sistema nervoso central necessita se preparar para uma ação motora. Por outro lado, o córtex parieto-occipital, o qual está envolvido com processos de atenção, demonstrou uma maior assimetria no hemisfério direito, o que implica uma participação dessa área em estratégias cognitivas para uma tarefa particular. Então, podemos concluir que o procedimento experimental adotado pode ser utilizado para explorar diferentes direções combinando tarefas de integração sensório-motora com diferentes...

Changes in quantitative EEG absolute power during the task of catching an object in free fall

The aim of this study was to verify changes in absolute power (qEEG), in theta, during the catch of a free falling object. The sample consisted of 10 healthy individuals, of both genders, with ages between 25 and 40 years. A three-way ANOVA followed by Post-Hoc analysis was applied. The results demonstrated main effects for time and position. In conclusion, a motor task that involves expectation produces deactivation of non-relevant areas in the ipsilateral hemisphere of the active limb. On the other hand, the patterns of results showed activation in areas responsible for planning and selection of motor repertories in the contralateral hemisphere.

O objetivo deste estudo foi verificar mudanças na potência absoluta (EEGq), em teta, durante a pegada de objeto em queda livre. A amostra consistiu de 20 indivíduos saudáveis, de ambos os gêneros, com idade entre 25 e 40 anos. Foi utilizada uma ANOVA three-way seguida de uma análise Post-Hoc. Os resultados demonstraram efeito principal para momento e posição. Concluindo, uma tarefa motora que envolve expectativa produz desativação de áreas não-relevantes no hemisfério ipsilateral do membro ativo. Por outro lado, o padrão dos resultados mostrou ativação em áreas responsáveis por planejamento e seleção de repertórios motores no hemisfério contralateral.

Os efeitos da estimulação elétrica funcional na assimetria cortical inter-hemisférica / The effects of functional electrical stimulation on cortical interhemispheric asymmetry

O objetivo do presente estudo foi avaliar os efeitos da estimulação elétrica funcional na assimetria cortical inter-hemisférica. Para tal, simultaneamente ao registro da atividade eletroencefalográfica, realizou-se eletroestimulação no antebraço direito para estimulação da extensão do indicador. A amostra consistiu de 45 sujeitos randomizados em 3 grupos de 15 sujeitos cada: grupo controle (submetido a 24 blocos de estimulação com intensidade de corrente zero), grupo 1 (24 blocos) e grupo 2 (36 blocos). A assimetria entre os pares de eletrodos F3-F4, C3-C4 e P3-P4 foi analisada ao longo dos grupos através de uma Anova. Os resultados apontaram para uma interação grupo x eletrodo e uma tendência de diminuição da assimetria inter-hemisférica após a eletroestimulação.

The aim of the present study was to assess the effects of functional electrical stimulation (FES) on cortical interhemispheric asymmetry. Electrostimulation was performed on the right forearm to stimulate the extension of the index finger. EEG activity was recorded simultaneously. The sample included 45 subjects randomly divided into 3 groups of 15 subjects each: control group (submitted to 24 blocks of stimulation at a null intensity current), group 1 (24 blocks) and group 2 (36 blocks). Interhemispheric asymmetry between F3-F4, C3-C4 and P3-P4 was analyzed through an Anova. Results pointed out to a group x electrode interaction and a general tendency of asymmetry decrease after stimulation.

What we see is how we are: New paradigms in visual research

As most sensory modalities, the visual system needs to deal with very fast changes in the environment. Instead of processing all sensory stimuli, the brain is able to construct a perceptual experience by combining selected sensory input with an ongoing internal activity. Thus, the study of visual perception needs to be approached by examining not only the physical properties of stimuli, but also the brain's ongoing dynamical states onto which these perturbations are imposed. At least three different models account for this internal dynamics. One model is based on cardinal cells where the activity of few cells by itself constitutes the neuronal correlate of perception, while a second model is based on a population coding that states that the neuronal correlate of perception requires distributed activity throughout many areas of the brain. A third proposition, known as the temporal correlation hypothesis states that the distributed neuronal populations that correlate with perception, are also defined by synchronization of the activity on a millisecond time scale. This would serve to encode contextual information by defining relations between the features of visual objects. If temporal properties of neural activity are important to establish the neural mechanisms of perception, then the study of appropriate dynamical stimuli should be instrumental to determine how these systems operate. The use of natural stimuli and natural behaviors such as free viewing, which features fast changes of internal brain states as seen by motor markers, is proposed as a new experimental paradigm to study visual perception.

The design of intelligentized FES system on ERD/ERS signals / 生物医学工程学杂志

Our objective is the designing of a functional electrical stimulation (FES) system on event related desynchronization (ERD) and event related synchronization (ERS) signals. When the brain images the left-and right-leg movements, the ERD/ERS signals will appear. By characterization and characteristic classification, the ERD/ERS will be translated into the response control signal for operating the FES system to electrically stimulate the legs of motor disability. The result shows that the experiment is successful in electrically stimulating the legs of motor disability.

Off-line experiments and analysis of independent brain--computer interface / 生物医学工程学杂志

In order to study event-related desynchronization (ERD) related to voluntary movement, we designed two experiments. In the first experiment, untrained subjects were required to imagine the action of typing with left or right index finger for about 1 second before real action, whereas they were required to type instantly after instruction in the second experiment. By analyzing spontaneous EEG signals between the instruction and the action, we predicted which finger was used. The prediction accuracy in the first experiment fell from 85% to 71% with the progress of experiment, the average accuracy being 78%, whereas the prediction result was almost random guess in the second experiment. The results demonstrate that (1) ERD patterns are significantly affected by the effective duration of motion imagination, (2) unconscious reduction of this duration can decrease the prediction accuracy. Therefore, when designing subsequent BCI experiments, we should devote our attention to the question of how to keep the effective duration of motion imagination.

Discrimination between left and right hand movement imagery event-releated EEG pattern / 生物医学工程学杂志

Left and right hand movement imagery can modifty the neural activity in the primary sensorimotor areas in a very similar way as observable with a real executed movement, leading to the special changes of EEG components such as event-related desynchronization/synchronization (ERD/ERS). Quick and correct classification of these event-related EEG pattern can be used to help patients with severe paralysis to move a cursor or orthosis to replace impaired motor function and provide a new communicatoion channel to environment. In this paper left and right hand movement imagery experiment method was introduced, some kinds of classification methods for event-related EEG pattern during motor imagery were reviewed and the prospect of classification methods was also put forward.

EEG alpha desynchronization from rest to silent reading in school children

Objetivo: estudiar la asimetría cerebral en el electroencefalograma (EEG) durante la realización de una tarea de lectura silente. Métodos: se estudió un grupo de escolares durante una tarea de lectura silente buscando lateralización cerebral para el procesamiento verbal, hipotetizando que hay una desincronización asimétrica en la banda alfa provocada por la actividad cognoscitiva. Se estudiaron 25 escolares masculinos de 9-10 años con nivel de lectura adecuado a su edad, provenientes de escuelas públicas y privadas de la Ciudad de México. Se les realizó un estudio de EEG de 16 canales, los registros fueron realizados en reposo con los ojos cerrados y posteriormente durante la lectura en silencio de un texto con material acorde a su edad. El EEG fue analizado por medio de la transformada rápida de Fourier. Se calculó la potencia relativa por espectro de frecuencia dividido en las bandas: delta, theta, alfa, beta-1, beta-2, beta-3. Se compararon los datos de reposo y lectura en las bandas alfa y beta. Resultados: se observaron diferencias significativas en la distribución regional de la potencia relativa durante la lectura asociadas a un reducción generalizada de la actividad alfa, principalmente en el hemisferio izquierdo, así como un incremento frontal de los ritmos beta-2 y beta-3 durante la lectura. Conclusiones: la lectura silente puede producir una desincronización lateralizada del EEG con una reducción de la actividad alfa de predominio en el hemisferio izquierdo; así como, un aumento de los ritmos beta frontales, estas zonas son de conocida participación en el procesamiento del lenguaje.

Cardiovascular and respiratory changes during slow-wave sleep in rats are associated with electrocorticogram desynchronization

In awake rats a single recurrent larger tidal volume (deep breaths) occurs at regular intervals, followed by oscillations in arterial pressure and heart rate. In the present study we recorded the changes in blood pressure, heart rate and ventilation during the wakefulness-sleep cycle identified by electrocorticographic records in order to determine whether the deep breaths and cardiovascular oscillations were associated with changes in the electrocorticogram. During several episodes of slow-wave sleep (SWS) in 7 rats the deep breaths and oscillations in arterial pressure and heart rate were preceded by SWS desynchronization. The interval between deep breaths during SWS was 71 + 4 s, the period between initial desynchronization and the generation of deep breaths was 3.98 + 0.45 s and the duration of SWS desynchronization was 11 + 0.65 s. Hypotension (-16 + 1 mmHg) and tachycardia (+15 + 5 bpm) were observed during deep breaths in the SWS state. These data indicate that the oscillations in arterial pressure and heart rate during SWS are associated with deep breaths, which in turn are preceded by desynchronization of the electrocorticogram in this state of sleep.

Disruptive effect of the mesencephalic reticular formation on tonic immobility in guinea pigs

Cholinergic stimulation of the mesencephalic reticular formation with carbachol impairs the induction of tonic immobility (TI) by restreining maneuvers and reduces the duration of immobility episodes in guiena pigs TI which permits the animal to evaluate the best6 time for escape. It is possible that this monitoring inolves cirucits and neurotransmitters other than the ascending cholinergic system origination in the mesencephalic reticular formation

A parametric model for multichannel EEG spectra

El EEG es modelado como la superposición de dos procesos componentes: y alfa. En el dominio de la frecuencia, el proceso siempre está presente y aparece como un pico espectral centrado en o Hz, mientras que el pico espectral del proceso alfa está centrado en la banda tradicional alfa (17-13 Hz), y no siempre está presente. Se postula que el processo es generado por el sistema de proyección tálamo-cortical generalizado y que su propagación ocurre mediante conecciones corticales de corto alcance, mientras que el proceso alfa está relacionado al sistema de proyección tálamo-cortical específico y se propaga vía fibras de asociación cortico-corticales de largo alcance