TY - JOUR
T1 - Analysis and visualization methods for detecting functional activation using laser speckle contrast imaging
AU - Hu, Peng
AU - Niu, Bochao
AU - Yang, Hang
AU - Xia, Yang
AU - Chen, Donna
AU - Meng, Chun
AU - Chen, Ke
AU - Biswal, Bharat
N1 - Funding Information: The authors declare no external funding. Publisher Copyright: © 2022 John Wiley & Sons Ltd.
PY - 2022/10
Y1 - 2022/10
N2 - 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.
AB - 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.
KW - brain functional activation
KW - cerebral blood flow
KW - correlation coefficient
KW - fast Fourier transform
KW - general linear model
KW - laser speckle contrast imaging
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U2 - https://doi.org/10.1111/micc.12783
DO - https://doi.org/10.1111/micc.12783
M3 - Article
C2 - 36070200
SN - 1073-9688
VL - 29
JO - Microcirculation
JF - Microcirculation
IS - 6-7
M1 - e12783
ER -