Deep brain stimulation of the subthalamic nucleus improves set shifting but does not affect dual task performance in Parkinson's disease.

Problems with shifting attentional set and concurrent performance of tasks are key cognitive deficits in Parkinson's disease (PD). Our aim was to examine the effects of deep brain stimulation of the subthalamic nucleus on tests of set shifting and dual task performance in patients with PD. Twelve patients with PD were assessed on tests of set shifting and on dual task performance with subthalamic nucleus (STN) stimulation switched on and off in a counterbalanced order. All patients obtained a clinical benefit from deep brain stimulation (DBS) of the STN. STN stimulation significantly improved set shifting. The effect of DBS on dual task performance was not significant. Change in measures of set shifting was significantly associated with the change in the motor symptoms of PD with DBS. The improved set shifting with DBS of the STN in PD supports the critical role of the striato-frontal circuits in this cognitive function.     

Coupled Oscillatros: Complex But Not Complicated Cardiovascular and Brain Interactions

In coupled nonlinear oscillators approach, the framework that has been used for the studies of cardiovascular and brain oscillations. As background, it describes the human CVS and present results of time-frequency analysis using wavelet transforms of several noninvasive measurements of cardiovascular signals. Studies of neuronal oscillations have been undertaken since the first human electroencephalographic (EEG) recording, and the recent resurgence of interest in neuronal oscillations. It is concluded that interactions occur between the oscillatory processes, both within and between the cardiovascular and the neuronal systems. The strengths and directions of these interactions may be used, in principle, for characterization of the state of the organism as demonstrated here for the case of deep anesthesia.     

Transient global brain ischemia in young and aged rats: differences in severity and progression, but not localisation, of lesions evaluated by magnetic resonance imaging

A model of transient global brain ischemia consisting of bilateral occlusion of common carotid arteries for 10 min and mild hypoxia (15% O₂−85% N₂) for 20 min was studied by means of MRI in young and aged Fischer 344 rats (3–4 and 24–26 months, respectively). Ischemia was assessed by full suppression of spontaneous EEG activity, which reappeared and normalized similarly in the two age-groups. The survival of young with respect to aged rats was considerably higher both at 24 h (20/20, i.e. 100% vs 12/16, i.e. 75%) and at 48 h (16/20, i.e. 80% vs 6/16, i.e. 38%). The localisation of brain lesions, their severity and progression were evaluated by a diffusion-weighted MRI (DWI) sequence at 24 and 48 h post-ischemia. There were no DWI-detectable lesions in eight out of 20 young and two out of 12 aged rats. The localisation of DWI-detected lesions was rather similar in rats of the two age-groups. In fact, the cerebral cortex, mainly parietal, occipital and temporal lobes were damaged in 83% of young and 90% of aged rats. The respective percentages for the thalamus were 83 and 60%, for the striatum 58 and 50%, and for the hippocampus 25 and 30%. The lesions present in the cerebral cortex and the thalamus were considerably more severe in aged than in young rats. In conclusion, in spite of similar localisation of ischemic lesions in the two age-groups, their incidence was higher, appearance more rapid and severity more pronounced in aged with respect to young rats. This resulted in a considerably higher mortality of the former. The overall data indicate that the age issue is very important in experimental ischemia research.     

Contribution to the theory of weakly nonlinear oscillators: Part I. An estimation of amplitude and frequency

Steady state signal in an oscillator is described by a nonlinear integral equation. A new theorem on the existence of an isolated number ω, for which the equation has a periodic eigensolution of period 2π/ω is given in the paper. An approximate value ω and approximate eigensolution can be easily obtained by the describing function method. The main result of the paper is the presentation of an effective estimation of the error of this approximation for weakly nonlinear oscillators.     

Perceptualization of biomedical data. An experimental environmentfor visualization and sonification of brain electrical activity

Complex experiments require sophisticated visualization of a large number of parameters. However, physiological characteristics of human perception limit the number of visualized parameters and their dynamics. Multimodal data presentation could increase throughput, introduce new data streams, and improve temporal resolution. The future of biomedical data presentation will probably be marked with multimodal data presentation and integration of multiple diagnostic procedures. Here, the authors present sonification as a second presentation modality. During analysis, multimodal parameters must be set to maximize the distance of changes in the perceptual domain. The authors implemented sonification in their 3D EEG visualization environment to render synesthetic extension of a selected data channel or to introduce new composite parameters. Sonification improved the ability to assess genuine dynamics of brain electrical activity and to perceive inherent spatio-temporal patterns of brain electrical activity     

Performances evaluation and optimization of brain computer interface systems in a copy spelling task.

The evaluation of the performances of brain-computer interface (BCI) systems could be difficult as a standard procedure does not exist. In fact, every research team creates its own experimental protocol (different input signals, different trial structure, different output devices, etc.) and this makes systems comparison difficult. Moreover, the great question is whether these experiments can be extrapolated to real world applications or not. To overcome some intrinsic limitations of the most used criteria a new efficiency indicator will be described and used. Its main advantages are that it can predict with a high accuracy the performances of a whole system, a fact that can be used to successfully improve its behavior. Finally, simulations were performed to illustrate that the best system is built by tuning the transducer (TR) and the control interface (CI), which are the two main components of a BCI system, so that the best TR and the best CI do not exist but just the best combination of them.     

Amplitude- and frequency-dependent changes in neuronal regularity parallel changes in tremor With thalamic deep brain stimulation.

The mechanisms by which deep brain stimulation (DBS) alleviates tremor remain unclear, but successful treatment can be achieved with properly selected frequency and amplitude. The clinical tremor response to thalamic DBS for essential tremor is dependent on the stimulation frequency and amplitude, and for high frequencies (> or = 90 Hz), increasing amplitude suppressed tremor, whereas for low frequencies (< 60 Hz), increasing amplitude aggravated tremor. We studied the effects of stimulation frequency and amplitude on the output of a population of intrinsically active model neurons to test the hypothesis that regularization of neuronal firing patterns is responsible for the clinical effectiveness of DBS. The firing patterns of model thalamocortical neurons were dependent on stimulation frequency and amplitude in a manner similar to the clinical tremor response. Above a critical frequency, increasing amplitude reduced the coefficient of variation (CV) of the neuronal firing pattern, whereas for low frequencies, increasing the amplitude increased the CV of neuronal activity. The correlation between the changes in tremor and the changes in the CV of neuronal firing supports the hypothesis that regularization of neuronal firing pattern during DBS is one of the mechanisms underlying the suppression of tremor.     

配合物Ni_2（ad）_3Cl．6H_2O的结构与磁性研究

在Ｍｉｋｕｌｓｋｉ等人实验的基础上，利用配位场方法，分析了实测Ｎｉ２（ａｄ）３Ｃｌ．６Ｈ２Ｏ的电子吸收光谱，确定了具有生理活性的有机金属配合物Ｎｉ２（ａｄ）３Ｃｋｌ．６Ｈ２Ｏ的空间构型与光谱参量，理论计算的磁矩和实验观测结果一致．     

300MW发电机空负荷和非全相暂态过程计算机仿真及分析

本文针对太原第一热电厂汽轮发电机组空负荷和非全相问题，通过建立派克模型进行了暂态过程的计算机仿真计算，并对仿真计算的结果进行了分析探讨。     

Neural ensemble activity from multiple brain regions predicts kinematic and dynamic variables in a multiple force field reaching task.

In everyday life, we reach, grasp, and manipulate a variety of different objects all with their own dynamic properties. This degree of adaptability is essential for a brain-controlled prosthetic arm to work in the real world. In this study, rats were trained to make reaching movements while holding a torque manipulandum working against two distinct loads. Neural recordings obtained from arrays of 32 microelectrodes spanning the motor cortex were used to predict several movement related variables. In this paper, we demonstrate that a simple linear regression model can translate neural activity into endpoint position of a robotic manipulandum even while the animal controlling it works against different loads. A second regression model can predict, with 100% accuracy, which of the two loads is being manipulated by the animal. Finally, a third model predicts the work needed to move the manipulandum endpoint. This prediction is significantly better than that for position. In each case, the regression model uses a single set of weights. Thus, the neural ensemble is capable of providing the information necessary to compensate for at least two distinct load conditions.     

The power black hole - The cost of power and the security of supply is a growing concern, but many data centre managers are neglecting this important issue.

The cost of power and the security of supply is a growing concern, but many data centre managers are neglecting this important issue. Many fail to take into account the energy consumed by the storage of their ever-expanding base of data. Reducing ongoing power needs with better overall design, planning and data center management should be just as a key concern as disaster recovery and backup plans already are for business. Fortunately, an array of products is available to handle real-world challenges of high power densities and cooling in IT environments. Data center outsourcing is another option that is growing in popularity among businesses. Finally, advances in research into direct current power distribution in the data center are expected to provide more energy savings     

I. W. Sandberg, ‘Linear shift‐invariant input–output maps do not necessarily commute’. International Journal of Circuit Theory and Applications, 2000; 28:513–518.

The original article to which this Erratum refers was published in the International Journal of Circuit Theory and Applications, 2000; 28 :513–518.