Mathematical modelling for biomagnetic localization

Non-invasive biomagnetic measurements are feasible for obtaining functional information concerning the electrical activity of the human heart and brain. These methods have turned out to be promising in localizing various bioelectric sources in the body. For example, in magnetocardiographic studies of localizing arrhythmogenic tissue and both normal and abnormal conduction pathways between the atria and the ventricles, the best accuracies reported are comparable to the results obtained by the invasive methods. We consider here basic principles of biomagnetic source localization methods, focusing on the magnetocardiographic mapping.     

Localization and detection of visual stimuli in monkeys with pulvinar lesions

Summary Since the pulvinar receives a major ascending projection of the superior colliculus, pulvinar lesions might produce behavioral impairments resembling those that follow colliculus lesions. To test this possibility, we examined the effect of pulvinar lesions in monkeys on the localization and detection of brief light flashes, a task in which monkeys with colliculus lesions are severely impaired. Some of the pulvinar-lesioned monkeys showed localization impairments similar to those in monkeys with colliculus lesions. However, histological analyses of the lesions suggested that these deficits were related not to the pulvinar damage per se, but rather to interruption of corticotectal fibers that pass through the pulvinar. We conclude that the pulvinar is not critical for the ability to locate and detect brief visual stimuli.Supported by research grants MH 26489 from the National Institute of Mental Health and EY02254 from the National Eye Institute     

Volumetric and histological changes in the cochlear nuclei of visually deprived rats: a possible morphological basis for intermodal sensory compensation.

The cochlear nucleus of 90 day-old rats was studied to determine whether bilateral visual deafferentation at birth induced compensatory structural changes in the auditory system. Computer-assisted reconstructions of the cochlear nucleus were used to demonstrate the three-dimensional organization of the nucleus and for calculating volumes of the subdivisions. In enucleated rats the volume of the granular region of the nucleus (GCD) increased 22.6% relative to controls, and the volume of the anterior ventral nucleus (AVCN) also increased by 10.0%. The posterior ventral nucleus (PVCN) and dorsal nucleus (DCN) were not affected. Since the volume change in GCD was substantial, this region was subjected to further analysis. Two types of granular cells were identified in the GCD of both control and enucleated rats with Kluver-Barrera staining. Type 1 cells contained an ovoid dark nucleus with clumpy chromatin and possessed only a very thin rim of cytoplasm. Type 2 cells were larger with pale spheroidal nuclei and with a more prominent cytoplasmic rim. There was an obvious stratification of these two cell types in the superficial layers over the lateral aspect of the AVCN in both groups. In contrast to this, the subpeduncular corner was not distinctively laminated and contained predominantly Type 2 cells. In enucleated animals the nuclear size of Type 1 cells increased by 3.8% while the size of Type 2 nuclei was not affected. Granule cell numbers increased by 28% in the visually deafferented rats. The GCD seems to be more highly developed in species which are dependent on non-visual modalities for spatial location. The regional hypertrophy of the GCD and AVCN seen in the present study may indicate that intermodal sensory compensation is taking place in the auditory system of visually deafferented rats.     

难治性癫痫的偶极子定位手术治疗

目的：探讨利用偶极子三维颅内癫痫病灶定位系统对难治性癫痫病患者致痫灶定位，进行外科手术治疗的效果。方法：对1999年8月至2001年6月在我院实施的259例难治性癫痫患者运用偶极子三维颅内癫痫病灶定位系统对难治癫痫患者致痫灶进行术前精确定位，指导采用相应多种方式手术治疗，并探讨其疗效及随访结果。结果：随访6-22月者180例，疗效满意112例，显著改善（发作减少75%以上）36例，良好（发作减少50%以上）22例，疗效差10例。总有效率为94%。显效率82%，未发现任何远期功能损害。结论：偶极子三维颅内癫痫病灶定位系统是目前用于明确癫痫病灶定位较为先进的方法，准确指导手术，可明显提高手术效果，并减少并发症的产生。     

Projections to the inferior colliculus from the anteroventral cochlear nucleus in the cat: possible substrates for binaural interaction

The projections to the inferior colliculus of the cat are shown in autoradiographs after injections of 3H-amino acids into the anteroventral cochlear nucleus and anterograde axonal transport. Labeled bands of axons are seen in the central nucleus of the inferior colliculus, parallel to the fibrodendritic laminae, and in layers 3 and 4 of the dorsal cortex. A bilateral projection to the lateral, low-frequency part of the inferior colliculus is observed. In contrast, the more ventromedial, mid- and high-frequency parts receive only a contralateral input. The projections from the cochlear nucleus to both the contralateral midbrain and bilaterally to the superior olivary complex appear to be tonotopically organized. After HRP injections in the inferior colliculus, small numbers of stellate neurons are labeled in the lateral and ventral low-frequency parts of the anteroventral cochlear nucleus on the ipsilateral side. EM autoradiographs show labeled axonal endings from both sides of the anteroventral cochlear nuclei are present in the same proportion in pars lateralis. Axonal endings from either cochlear nucleus have small, round synaptic vesicles and make asymmetric synaptic contacts on dendrites. Axons from the contralateral side also make axosomatic contacts on large disc-shaped or stellate cells. Neurons from the ipsilateral anteroventral cochlear nucleus apparently make more synaptic endings per cell as compared to neurons from the contralateral side. Together, bilateral inputs from the anteroventral cochlear nucleus can account for a third of the endings with round synaptic vesicles in pars lateralis of the central nucleus. Morphological similarities among the ascending inputs to the inferior colliculus are discussed. Both direct circuits from the cochlear nucleus to the inferior colliculus and indirect circuits via the superior olivary complex or lateral lemniscus may display banding patterns, nucleotopic organization, or differential synaptic organization. The direct inputs from the anteroventral cochlear nucleus to the colliculus may influence binaural interactions which occur in the superior olivary complex. In addition, direct inputs may create new binaural responses in the inferior colliculus that are independent of lower centers.     

录像脑电图联合偶极子定位法在癫癎外科的应用

目的：探讨顽固性癫癎病人进行录像脑电图（VEEG）监测和偶极子定位法（DLM）在癫癎灶定位的应用与价值。方法：回顾性分析300例顽固性癫癎病人的发作、VEEG检查及偶极子癫癎灶定位的准确性及影响因素。结果：对VEEG的直接人工分析定位率为80％，结合偶极子定位分析准确率可以达到94．3％，且均可以达到与术中皮层脑电图检查定位一致或基本一致。结论：利用128道长程VEEG偶极子定位法是一种方便、无创、准确的癫癎灶定位手段。     

细胞生长相关新基因PP3105的克隆及其初步功能研究

目的 新基因PP3105的克隆及其初步功能研究。方法 分离和克隆新基因PP3105的全长序列，在生物信息学分析的基础上，采用克隆形成、亚细胞定位、生长曲线等实验对该基因进行初步功能研究。结果 实验表明PP3105有两个不同的转录本，并表现出一定的组织特异性；染色体定位于4q22-24；蛋白定位于细胞膜和细胞浆中；克隆形成实验显示有明显的体外集落抑制作用；生长曲线实验表明PP3105在SMMC7721细胞中的表达对细胞增殖有抑制作用。结论 新基因PP3105可能是一个新的金属离子尤其是锌的转运蛋白，并且与肝癌细胞的生长、增殖相关。     

Immunohistochemical localization of creatine kinase-BB isoenzyme to astrocytes in human brain

Indirect immunoperoxidase labelling at the light microscope level using a specific antisera to brain type creatine kinase-BB isoenzyme has localized the protein to astrocytes in the white matter of human cerebrum. No specific staining of neurones or of other glial elements was detected.