High-resolution imaging of the immunological synapse and T-cell receptor microclustering through microfabricated substrates

T-cell activation via antigen presentation is associated with the formation of a macromolecular membrane assembly termed the immunological synapse (IS). The genesis of the IS and the onset of juxtacrine signalling is characterized by the formation of cell membrane microclusters and the organization of such into segregated microdomains. A central zone rich in T-cell receptor (TCR)–major histocompatibility complex microclusters termed the central supramolecular activation cluster (cSMAC) forms the bullseye of this structure, while the cellular interface surrounding the cSMAC is characterized by regions enriched in adhesion and co-stimulatory molecules. In vitro, the study of dynamic TCR microcluster coalescence and IS genesis in T-cell populations is hampered by cell migration within the culture system and resolution constraints resulting from lateral cell–cell contact. Here, we detail a novel system describing the fabrication of micropit arrays designed to sequester single T-cell–antigen presenting cell (APC) conjugates and promote IS formation in the horizontal imaging plane for high-resolution studies of microcluster dynamics. We subsequently use this system to describe the formation of the cSMAC in T-cell populations and to investigate the morphology of the interfacial APC membrane.     

大鼠胼胝体中突触结构的电镜观察

关于胼胝体中突触的在存在及其结构特点未见报道。选用２生后一周未睁眼Ｗｉｓｔａｒ大鼠４０只,随机分为摘除右侧眼球、左侧眼球、双侧眼球及正常对照四组,各组１０只。经灌流、固定、分别在胼胝体膝部、干部及压部取材后,电镜下观察了胼胝体中突触的结构。结果如下：１．胼胝 大多为化学性突触。２．各组及同组胼胝体各部中突触的美元数不同。３．胼胝体中突触数受视觉的影响。最后就胼胝体中突触的机能意义进行了讨论。     

类脑计算新发展——“TrueNorth”神经元芯片

类脑计算是一种基于神经网络的全新数据存储和计算技术,通过模拟大脑的工作机理,可以突破传统计算机处理大型问题时遇到的冯·诺依曼瓶颈,在显著提高信息处理速度的同时大幅降低功耗,并且具有自我学习和自适应能力。介绍了IBM最新研究的TrueNorth神经元芯片技术,包括其基本架构、工作原理、芯片性能、应用成果等,并展望了类脑计算技术的未来发展前景。