CPPM, Aix-Marseille Université, CNRS/IN2P3, Marseille, France.
Phys Med Biol. 2013 Jul 7;58(13):4483-500. doi: 10.1088/0031-9155/58/13/4483. Epub 2013 Jun 13.
The investigation of neurophysiological mechanisms underlying the functional specificity of brain regions requires the development of technologies that are well adjusted to in vivo studies in small animals. An exciting challenge remains the combination of brain imaging and behavioural studies, which associates molecular processes of neuronal communications to their related actions. A pixelated intracerebral probe (PIXSIC) presents a novel strategy using a submillimetric probe for beta(+) radiotracer detection based on a pixelated silicon diode that can be stereotaxically implanted in the brain region of interest. This fully autonomous detection system permits time-resolved high sensitivity measurements of radiotracers with additional imaging features in freely moving rats. An application-specific integrated circuit (ASIC) allows for parallel signal processing of each pixel and enables the wireless operation. All components of the detector were tested and characterized. The beta(+) sensitivity of the system was determined with the probe dipped into radiotracer solutions. Monte Carlo simulations served to validate the experimental values and assess the contribution of gamma noise. Preliminary implantation tests on anaesthetized rats proved PIXSIC's functionality in brain tissue. High spatial resolution allows for the visualization of radiotracer concentration in different brain regions with high temporal resolution.
研究大脑区域功能特异性的神经生理机制需要开发与小动物体内研究相适应的技术。一个令人兴奋的挑战仍然是将脑成像和行为研究结合起来，将神经元通讯的分子过程与其相关的行为联系起来。像素化脑内探针（PIXSIC）是一种新颖的策略，使用亚毫米探针进行基于像素化硅二极管的 beta(+)放射性示踪剂检测，该二极管可以被立体定向植入到感兴趣的脑区。这种完全自主的检测系统允许对放射性示踪剂进行时间分辨的高灵敏度测量，并在自由活动的大鼠中提供额外的成像特征。专用集成电路 (ASIC) 允许对每个像素进行并行信号处理，并实现无线操作。探测器的所有组件都经过了测试和特性描述。通过将探头浸入放射性示踪剂溶液中来确定系统的 beta(+)灵敏度。蒙特卡罗模拟用于验证实验值并评估伽马噪声的贡献。在麻醉大鼠上进行的初步植入测试证明了 PIXSIC 在脑组织中的功能。高空间分辨率允许以高时间分辨率可视化不同脑区的放射性示踪剂浓度。
