Data 1 of 3 for: Optical coherence tomography imaging of evoked neural activity in sciatic nerve of rat

Objective: To investigate changes in intensity, phase retardation, phase, and frequency spectra obtained from optical coherence tomography (OCT) images in response to evoked neural activity in sciatic nerve of rat in vitro.
Approach: M-scans with 20 μs temporal resolution were obtained on peripheral nerves of rat using a swept source polarisation sensitive optical coherence tomography (PS-OCT) system, while a nerve cuff acquired electrical neural recordings. From a total of 10 subjects: 3 had no stimulation (controls), 3 had paw stimulation, and 4 had nerve stimulation. Changes in the OCT signal intensity, phase retardation, phase, and frequency spectra were calculated for each subject and compared to the control subjects as well as reference samples of a mirror and microspheres in solution.
Main results: Observed changes in phase retardation and phase were not above the noise level of reference mirror sample. Observed changes in intensity in 3 paw stimulation and 2 nerve stimulation subjects and changes in frequency spectra amplitude in 2 paw stimulation were above the reference noise level. The delayed onset and extended duration of the changes in intensity and frequency spectra amplitude were temporally consistent with osmotic swelling from potassium ion currents in myelinated fibres which has previously been characterised in squid and crab nerve using light scattering techniques but has not been reported using OCT on myelinated fibres.
Significance: Imaging osmotic swelling in neural tissue using OCT signal intensity and frequency spectra creates exciting new possibilities for functional imaging in peripheral nerves and white matter of the brain.

研究目的：旨在探究在体外大鼠坐骨神经诱发的神经活动下，通过光学相干断层扫描（OCT）图像所获得的强度、相位延迟、相位和频谱的变化。研究方法：采用20 μs时间分辨率的M扫描，利用扫描源偏振敏感光学相干断层扫描（PS-OCT）系统对大鼠的周围神经进行扫描，同时通过神经袖套收集电神经记录。在总共10名受试者中，其中3名未接受刺激（对照组），3名接受足部刺激，4名接受神经刺激。对每位受试者的OCT信号强度、相位延迟、相位和频谱的变化进行了计算，并与对照组以及参考样品（镜子和溶液中的微球）进行了比较。主要结果：观察到的相位延迟和相位变化未超过参考镜样品的噪声水平。在3名足部刺激受试者和2名神经刺激受试者中观察到的强度变化，以及2名足部刺激受试者中频谱幅度变化均超过了参考噪声水平。强度和频谱幅度变化的延迟发生和持续时间与有髓鞘纤维中钾离子电流引起的渗透性肿胀相一致，这种肿胀先前已在乌贼和蟹神经中使用光散射技术进行了表征，但尚未使用OCT在有髓鞘纤维中进行报道。研究意义：利用OCT信号强度和频谱成像神经组织中的渗透性肿胀，为周围神经和大脑白质的机能成像开辟了令人兴奋的新途径。