Phase precession and phase-locking of hippocampal pyramidal cells.

We propose that the activity patterns of CA3 hippocampal pyramidal cells in freely running rats can be described as a temporal phenomenon, where the timing of bursts is modulated by the animal's running speed. With this hypothesis, we explain why pyramidal cells fire in specific spatial locations, and how place cells phase-precess with respect to the EEG theta rhythm for rats running on linear tracks. We are also able to explain why wheel cells phase-lock with respect to the theta rhythm for rats running in a wheel. Using biophysically minimal models of neurons, we show how the same network of neurons displays these activity patterns. The different rhythms are the result of inhibition being used in different ways by the system. The inhibition is produced by anatomically and physiologically diverse types of interneurons, whose role in controlling the firing patterns of hippocampal cells we analyze. Each firing pattern is characterized by a different set of functional relationships between network elements. Our analysis suggests a way to understand these functional relationships and transitions between them.     

基于颞叶癫痫脑电相位互相关分析法的癫痫超同步放电的初步研究

目的 分析颞叶癫痫患者病灶区和非病灶区脑电相位的同步关系,并与正常对照者比较,为癫痫发作的超同步放电机制提供支持.方法 选择经临床确诊且责任病灶为左颞区的颞叶癫痫患者20例和正常对照者10例,双侧颞区各放置4个记录电极,电极间距为20 mm.应用Hilbert变换提取以上脑电的相位,应用互相关方法分别计算左右两侧颞区每个区内每两导脑电相位间的互相关系数,结果用统计软件SPSS 10.0处理.结果 颞叶癫痫组病灶区与正常组左颞区脑电相位的平均互相关系数比较有显著性差异(P＜0.01);两组右侧脑电相位的平均互相关系数比较有显著性差异(P＜0.05).颞叶癫痫组病灶区与非病灶区脑电相位的平均互相关系数比较有显著性差异(P＜0.05);正常组两侧脑电相位的平均互相关系数比较无显著性差异.正常组脑电相位的最大互相关系数均位于两个相邻导联间,颞叶癫痫组37.5%的位于相隔导联间.结论 颞叶癫痫病灶区存在超同步放电现象,非病灶区也存在不同程度的超同步放电.     

A model for learning to segment temporal sequences, utilizing a mixture of RNN experts together with adaptive variance

This paper proposes a novel learning method for a mixture of recurrent neural network (RNN) experts model, which can acquire the ability to generate desired sequences by dynamically switching between experts. Our method is based on maximum likelihood estimation, using a gradient descent algorithm. This approach is similar to that used in conventional methods; however, we modify the likelihood function by adding a mechanism to alter the variance for each expert. The proposed method is demonstrated to successfully learn Markov chain switching among a set of 9 Lissajous curves, for which the conventional method fails. The learning performance, analyzed in terms of the generalization capability, of the proposed method is also shown to be superior to that of the conventional method. With the addition of a gating network, the proposed method is successfully applied to the learning of sensory–motor flows for a small humanoid robot as a realistic problem of time series prediction and generation.     

Moyamoya disease in a 12-year-old Caucasian boy presenting with acute transient psychosis

This paper reports the case of a 12-year-old boy who presented with an acute transient psychosis. Investigations revealed Moyamoya disease with occlusion of the left middle cerebral artery. There was no previous history of transient ischaemic attacks, no history of psychiatric disease, no family history of psychosis and no history of illicit drug use. Although no previous cases of Moyamoya disease with psychosis as the sole presenting feature have been described, we suggest the possibility of a causal link. Accepted: 23 December 1998     

The effect of chronic otitis media on the immunoreactivity of human inner ear

Twenty temporal bones (TBs) were removed from autopsy cases and prepared for immunohistochemical examination. Ten TBs were free of ear disease whereas the other ten TBs showed the signs of chronic otitis media. Expression of markers for monocyte-macrophages¶(25F9, 27E10) and natural killer cells (anti-Leu-11) was examined immunohistochemically. There were no specific positive stainings with 25F9 or anti-Leu-11 antibodies in any of the specimens. Staining for 27E10 was found to be negative in each section obtained from normal cochlea. However, 27E10 positivity was detected in three of ten TBs with signs of chronic ear inflammation. This positivity can be explained by two theories: (1) activated monocytes can enter the inner ear from the systemic circulation as a consequence of chronic antigen challenge; (2) mesothelial cells could become activated as a result of a cross-reaction, with resultant positivity. Development of sensorineural hearing loss in some cases of chronic otitis media may be due to these immunological reactions.     

肘管综合征的手术治疗

目的：探讨尺神经松解前移手术治疗肘管综合征的临床效果。方法：应用该术式治疗肘管综合征36例，观察尺侧上副动脉供血情况。结果：经随访。本组病例尺神经功能均有较大改善。结论：尺神经松解前移术为治疗肘管综合征的较佳术式。     

Approaches to the space-time modelling of infectious disease behaviour

A new approach to the space-time modelling of infectious diseasesis considered. A modulated heterogeneous Poisson process withintensity defined as a function of a two-dimensional susceptibilityfield is proposed. The model is fitted to a measles epidemicusing a proportional hazards approximation.     

新型弹性开放襻前房型人工晶体植入临床观察

本文采用巩膜隧道切口对白内障术后后囊不完整的９６例（７０只眼）行新型弹性开放襻前房型人工晶体（ＡｎｔｅｒｉｏｒＣｈａｍｂｅｒＩｎ－ｔｒａｏｃｕｌａｒＬｅｎｓ，ＡｃＩＯＬ）植入术。所有７０只眼术后矫正视力等于或超过术前最佳矫正视力。５２只眼（７４．３％）术后视力≥０．５。术后无严重并发症。结果显示新型弹性开放襻前房型人工晶体植入安全、有效     

Tibial bone bridge and bone block fixation in double-bundle anterior cruciate ligament reconstruction without hardware: a technical note

Current techniques for tibial graft fixation in four tunnels double bundle (DB) anterior cruciate ligament (ACL) reconstruction are by means of two interference screws or by extracortical fixation with a variety of different implants. We introduce a new alternative tibial graft fixation technique for four tunnels DB ACL reconstruction without hardware. About 3.5 to 5.5 cm bone cylinder with a diameter of 7 mm is harvested from the anteromedial (and posterolateral) tibial bone tunnel (s) with a core reamer. The anteromedial (AM) and posterolateral (PL) hamstring tendon grafts (or alternatively tendon allografts) are looped over an extracortical femoral fixation device and cut in length according to the total femorotibial bone tunnel length. The distal 3 cm of each, the AM- and PL bundle graft are armed with two strong No. 2 nonresorbable sutures and the four suture ends of each graft are tied to each other over the 2 cm wide cortical bone bridge between the tibial AM and PL bone tunnel. In addition the AM- and/or PL bone block which was harvested at the beginning of the procedure is re-impacted into the two tibial bone tunnels. A dorsal splint is used for the first two postoperative weeks and physiotherapy is started the second postoperative day. The technique is applicable for four tunnels DB ACL reconstruction in patients with good tibial bone quality. The strong fixation technique preserves important tibial bone stock and avoids the use of tibial hardware which knows disadvantages. It does increase tendon to bone contact and tendon-to-bone healing and does reduce implant costs to those of a single bundle (SB) ACL reconstruction. Revision surgery may be facilitated significantly but the technique should not be used when bony defects are present. In case of insufficient bone bridge fixation or bone blocks hardware fixation can be applied as usual. Not supported by outside funding or grant(s): No benefits in any form have been received, or will be received, from a commercial party related directly or indirectly to the subject of this article. The study complies with the current laws of the country, in which it was performed.