Overcoming temporal dispersion for measurement of activity-related impedance changes in unmyelinated nerves.
Overcoming temporal dispersion for measurement of activity-related impedance changes in unmyelinated nerves.
复制标题
克服时间分散，测量无髓神经活动相关的阻抗变化。
DOI：
10.1088/1741-2552/ac669a
复制
发表时间：
2022
影响因子：
4
通讯作者：
Aristovich,Kirill
中科院分区：
文献类型：
--
作者：
Tarotin,Ilya;Mastitskaya,Svetlana;Ravagli,Enrico;Perkins,JustinD;Holder,David;Aristovich,Kirill
目的快速神经电阻抗断层扫描是一种成像技术，通过测量伴随激励的阻抗变化（dZ），成功地可视化周围神经中有髓纤维的电诱发活动。然而，由于纤维传导速度的变化而发生时间色散（TP），无髓纤维的成像具有挑战性，并导致信号随着距刺激的距离而降低到噪声以下。为了克服 TP 并允许在无髓神经中进行电阻抗断层扫描成像，需要一种新的实验和信号处理范例，允许 dZ 测量距离刺激部位比可见的复合神经活动更远。这种范式的发展是本研究的主要目标。方法开发了猪膈下神经TP的基于有限元的统计模型，并在体外进行了实验验证。实施了神经刺激和结果数据处理的两种范例——连续刺激和刺激序列；确定了记录无髓神经中分散的 dZ 的最佳范例。主要结果虽然连续刺激和相干尖峰平均导致在距刺激物较近的距离处产生较高的信噪比 (SNR)，但火车的刺激在不同距离上更加一致，并且如果平均 30 分钟，则允许在距刺激物 15 厘米处进行 dZ 测量 (SNR= 1.8±0.8)。意义该研究开发了一种方法，用于首次允许在模拟和实验中在复合动作电位完全分散的距离处测量无髓神经的 dZ。
ObjectiveFast neural electrical impedance tomography is an imaging technique that has been successful in visualising electrically evoked activity of myelinated fibres in peripheral nerves by measurement of the impedance changes (dZ) accompanying excitation. However, imaging of unmyelinated fibres is challenging due to temporal dispersion (TP) which occurs due to variability in conduction velocities of the fibres and leads to a decrease of the signal below the noise with distance from the stimulus. To overcome TP and allow electrical impedance tomography imaging in unmyelinated nerves, a new experimental and signal processing paradigm is required allowing dZ measurement further from the site of stimulation than compound neural activity is visible. The development of such a paradigm was the main objective of this study.ApproachA finite element-based statistical model of TP in porcine subdiaphragmatic nerve was developed and experimentally validated ex-vivo. Two paradigms for nerve stimulation and processing of the resulting data—continuous stimulation and trains of stimuli, were implemented; the optimal paradigm for recording dispersed dZ in unmyelinated nerves was determined.Main resultsWhile continuous stimulation and coherent spikes averaging led to higher signal-to-noise ratios (SNRs) at close distances from the stimulus, stimulation by trains was more consistent across distances and allowed dZ measurement at up to 15 cm from the stimulus (SNR= 1.8±0.8) if averaged for 30 min.SignificanceThe study develops a method that for the first time allows measurement of dZ in unmyelinated nerves in simulation and experiment, at the distances where compound action potentials are fully dispersed.