Multichannel single trial MEG of cortical population spikes – SPIKE MEG

皮质群峰值的多通道单试验 MEG – SPIKE MEG

• 批准号: 511192033
• 负责人: Dr. Rainer Körber, Ph.D.
• 金额: --
• 依托单位: Abteilung 8 - Medizinphysik und metrologische Informationstechnik
• 依托单位国家: 德国
• 项目类别: New Instrumentation for Research
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/511192033?language=en
• 关键词: Multichannel; single; trial; MEG; cortical

Evolution has shaped the human brain as a “single-trial” processor reacting fast and reliably to environmental events, and the cerebral processing of information is one of the body’s most complex processes. The demand to observe the brain’s operation ‘at the speed of thought’, but without the need to place electrodes inside the brain, inspired two temporally high-resolution techniques: electroencephalography (EEG) and magnetoencephalography (MEG) which rely on measuring the electromagnetic field originating from ionic neuronal currents. These can be categorized as slow and fast currents having different microscopic origins: Slow currents—known as postsynaptic potentials—occur when impulse signals, fired by one nerve cell, are received by another. The firing of such impulses (which transmit information to downstream neurons or muscles) produces fast currents which last for just a millisecond – these 'spikes' are known as action potentials. However, while results for slow currents from EEG and MEG are reliable, those for fast currents in general are not. The Physikalisch-Technische Bundesanstalt (PTB) is a spearhead in the development of MEG technology, and its recently constructed ultralow-noise magnetometer enabled the first non-invasive single-trial characterization of evoked human cortical population spikes, revealing amplitudes highly variable between trials and intertrial correlated response latencies. These unique recordings opened up the prospect that low-noise MEG might enable integral non-invasive measurements of neuronal currents at both low and high frequencies. However, these pilot measurements were performed with a single-channel MEG device, precluding analysis of individual neuronal sources in the orchestrated network activity of the cortical network. The proposed project will build on this momentum and design and construct a novel ultralow-noise multichannel MEG system that will enable spatially resolved non-invasive measurements of both slow synaptic currents and fast spiking activity at the same time. We will also make use of the complementary nature of EEG and MEG which have different spatial sensitivities to neuronal source characteristics by integrating our previous experience on low-noise EEG. Neurologists from Charité-Universitätsmedizin Berlin team up with physicists and engineers from PTB to answer questions that conventionally call for invasive microelectrode recordings. We will examine the hypothesis that neuronal oscillations (slow currents) in the somatosensory cortex affects local spiking behavior (fast currents) and that spiking in one part of the somatosensory cortex inhibits concurrent spiking activity in neighboring regions. The iterative interaction and tight integration of technologic and physiologic expertise in this project is key to the development of a novel ultralow-noise MEG/EEG device that will be transformative for human non-invasive neurophysiology.

进化已经将人类大脑塑造成一个对环境事件做出快速可靠反应的“单次试验”处理器，大脑对信息的处理是人体最复杂的过程之一。人们需要“以思考的速度”观察大脑的运作，但不需要在大脑中放置电极，这激发了两种暂时高分辨率的技术：脑电图（EEG）和脑磁图（MEG），它们依赖于测量离子神经元电流产生的电磁场。这些电流可以分为慢电流和快电流，它们有不同的微观起源：慢电流——被称为突触后电位——发生在一个神经细胞发出的脉冲信号被另一个神经细胞接收时。这种脉冲（将信息传递给下游的神经元或肌肉）的放电会产生持续一毫秒的快速电流——这些“尖峰”被称为动作电位。然而，虽然脑电图和脑磁图的慢电流结果是可靠的，但那些快速电流的结果通常并不可靠。德国物理技术研究所（physical - isch- technische Bundesanstalt， PTB）是脑磁图技术发展的先锋，其最近研制的超低噪声磁强计首次实现了对诱发的人类皮层峰值的非侵入性单次试验表征，揭示了试验之间高度可变的振幅和试验间相关的反应潜伏期。这些独特的记录打开了低噪声脑磁图的前景，使其能够在低频率和高频率下对神经元电流进行完整的非侵入性测量。然而，这些初步测量是用单通道MEG设备进行的，排除了对皮质网络协调网络活动中的单个神经元源的分析。该项目将在此基础上设计和构建一种新型的超低噪声多通道脑磁图系统，该系统将能够同时对慢速突触电流和快速尖峰活动进行空间分辨非侵入性测量。我们还将结合以往在低噪声脑电方面的经验，利用脑电信号和脑电信号对神经元源特征具有不同空间敏感性的互补性。来自Charité-Universitätsmedizin柏林的神经学家与PTB的物理学家和工程师合作，回答传统上需要侵入性微电极记录的问题。我们将检验以下假设：体感皮层的神经元振荡（慢电流）影响局部尖峰行为（快电流），而体感皮层某一部分的尖峰会抑制邻近区域的同步尖峰活动。在这个项目中，技术和生理学专业知识的反复互动和紧密结合是开发一种新型超低噪声MEG/EEG设备的关键，这将改变人类非侵入性神经生理学。