Analysis and visualization methods for detecting functional activation using laser speckle contrast imaging

IF 1.9 4区医学 Q3 HEMATOLOGY Microcirculation Pub Date : 2022-09-07 DOI:10.1111/micc.12783

Peng Hu, Bochao Niu, Hang Yang, Yang Xia, Donna Chen, Chun Meng, Ke Chen, Bharat Biswal

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引用次数: 2

Abstract

Background

Previous studies have used regional cerebral blood flow (CBF) hemodynamic response to measure brain activities. In this work, we use a laser speckle contrast imaging (LSCI) apparatus to sample the CBF activation in somatosensory cortex (S1BF) with repetitive whisker stimulation. Traditionally, the CBF activations were processed by depicting the change percentage above baseline; however, it is not clear how different methods influence the detection of activations.

Aims

Thus, in this work we investigate the influence of different methods to detect activations in LSCI.

Materials & Methods

First, principal component analysis (PCA) was performed to denoise the CBF signal. As the signal of the first principal component (PC1) showed the highest correlation with the S1BF CBF response curve, PC1 was used in the subsequent analyses. Then, we used fast Fourier transform (FFT) to evaluate the frequency properties of the LSCI images and the activation map was generated based on the amplitude of the central frequency. Furthermore, Pearson's correlation coefficient (C–C) analysis and a general linear model (GLM) were performed to estimate the S1BF activation based on the time series of PC1.

Results

We found that GLM performed better in identifying activation than C–C. Additionally, the activation maps generated by FFT were similar to those obtained by GLM. Particularly, the superficial vein and arterial vessels separated the activation region as segmented activated areas, and the regions with unresolved vessels showed a common activation for whisker stimulation.

Discussion and Conclusion

Our research analyzed the extent to which PCA can extract meaningful information from the signal and we compared the performance for detecting brain functional activation between different methods that rely on LSCI. This can be used as a reference for LSCI researchers on choosing the best method to estimate brain activation.

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利用激光散斑对比成像检测功能激活的分析和可视化方法

以往的研究使用脑区域血流动力学反应(CBF)来测量脑活动。在这项工作中，我们使用激光散斑对比成像(LSCI)设备对重复须刺激体感觉皮层(S1BF)的CBF激活进行了采样。传统上，CBF激活是通过描述高于基线的变化百分比来处理的;然而，目前尚不清楚不同的方法如何影响激活检测。因此，在这项工作中，我们研究了不同方法检测LSCI激活的影响。材料,方法首先采用主成分分析(PCA)对脑血流信号进行去噪处理。由于第一主成分(PC1)信号与S1BF CBF响应曲线的相关性最高，因此将PC1用于后续分析。然后，利用快速傅里叶变换(FFT)对LSCI图像的频率特性进行评估，并根据中心频率的幅值生成激活图;基于PC1的时间序列，采用Pearson相关系数(C-C)分析和一般线性模型(GLM)估计S1BF的激活。结果我们发现GLM比C-C更能识别激活。此外，FFT生成的激活图与GLM获得的激活图相似。特别是，浅表静脉和动脉血管将激活区分离为分段激活区，并且未解决的血管区域显示出对须刺激的共同激活。我们的研究分析了PCA从信号中提取有意义信息的程度，并比较了依赖LSCI的不同方法在检测脑功能激活方面的性能。这可以为LSCI研究者选择最佳的脑激活估计方法提供参考。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Microcirculation 医学-外周血管病

CiteScore

5.00

自引率

4.20%

发文量

审稿时长

6-12 weeks

期刊介绍： The journal features original contributions that are the result of investigations contributing significant new information relating to the vascular and lymphatic microcirculation addressed at the intact animal, organ, cellular, or molecular level. Papers describe applications of the methods of physiology, biophysics, bioengineering, genetics, cell biology, biochemistry, and molecular biology to problems in microcirculation. Microcirculation also publishes state-of-the-art reviews that address frontier areas or new advances in technology in the fields of microcirculatory disease and function. Specific areas of interest include: Angiogenesis, growth and remodeling; Transport and exchange of gasses and solutes; Rheology and biorheology; Endothelial cell biology and metabolism; Interactions between endothelium, smooth muscle, parenchymal cells, leukocytes and platelets; Regulation of vasomotor tone; and Microvascular structures, imaging and morphometry. Papers also describe innovations in experimental techniques and instrumentation for studying all aspects of microcirculatory structure and function.