Transcranial chronic optical access to longitudinally measure cerebral blood flow

Opening a window to the acutely injured brain: Simultaneous retinal and cerebral vascular monitoring in rats

Many recent research projects have described typical chronic changes in the retinal vasculature for diverse neurovascular and neurodegenerative disorders such as stroke or Alzheimer's disease. Unlike cerebral vasculature, retinal blood vessels can be assessed non-invasively by retinal vessel analysis. To date, there is only a little information about potential simultaneous reactions of retinal and cerebral vessels in acute neurovascular diseases. The field of applications of retinal assessment could significantly be widened if more information about potential correlations between those two vascular beds and the feasibility of non-invasive retinal vessel analysis in acute neurovascular disease were available. Here, we present our protocol for the simultaneous assessment of retinal and cerebral vessels in an acute setting in anesthetized rats using a non-invasive retinal vessel analyzer and a superficial tissue imaging system for laser speckle contrast analysis via a closed bone window. We describe the experimental set-up in detail, outline the pitfalls of repeated retinal vessel analyses in an experimental set-up of several hours, and address issues that arise from the simultaneous use of two different assessment tools. Finally, we demonstrate the robustness and variability of the reactivity of retinal vessels to hypercapnia at baseline as well as their reproducibility over time using two anesthetic protocols common for neurovascular research. In summary, the procedures described in this protocol allow us to directly compare retinal and cerebral vascular beds and help to substantiate the role of the retina as a "window to the brain."

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

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.

Effects of Transcranial Magnetic Stimulation Combined with Computer-Aided Cognitive Training on Cognitive Function of Children with Cerebral Palsy and Dysgnosia

Objective

This study is aimed at researching transcranial magnetic stimulation (TMS) effects combined with computer-aided cognitive training (CACT) on cognitive function of children suffering from cerebral palsy and dysgnosia.

Methods

From December 2019 to October 2021, 86 children with cerebral palsy and dysgnosia who were treated at our hospital were recruited and assigned into observation and control groups (n = 43, each) using the random number table technique. The observation group received TMS combined with CACT (TMS+CACT), whereas the control group received only TMS. Chinese Wechsler Young Children Scale of Intelligence (C-WYCSI) and Chinese-Wechsler Intelligence Scale for Children (C-WISC) were used to evaluate the intelligence level of the two groups; Gross Motor Function Measure-88 (GMFM-88) of Fudan Chinese version was employed for evaluating the gross motor function of the two groups; a comparison was drawn among the two groups for the cerebral hemodynamic parameters before and after the treatment.

Results

For young children, the verbal intelligence quotient (VIQ) scores at 6 and 12 weeks of treatment in the observation group were increased when compared to those in the control group (48.91 ± 3.70 vs. 47.32 ± 3.33, 54.25 ± 4.46 vs. 49.48 ± 3.36), and the observation group's performance intelligence quotient (PIQ) score at 12 weeks of treatment was higher as to that of the control group (65.38 ± 4.23 vs. 62.81 ± 4.74, all P < 0.05). For older age children, the observation group's VIQ and PIQ scores were greater than the control group's at 6 and 12 weeks of treatment, with statistical significance (63.80 ± 3.76 vs. 59.50 ± 5.32, 74.64 ± 12.04 vs. 65.08 ± 6.30; 63.91 ± 5.96 vs. 58.42 ± 3.70, 72.73 ± 5.06 vs. 66.42 ± 5.93; all P < 0.05). The GMFM-88 scale scores in both groups were increased after 6 and 12 weeks of treatment. After treatment for 12 weeks, the observation group's A-E scores were greater than those of the control group (all P < 0.05). The peak systolic velocity (V s), end-diastolic velocity (V d), and mean velocity (V m) at the anterior cerebral artery (ACA), middle cerebral artery (MCA), and posterior cerebral artery (PCA) in the observation group were dramatically increased than those in the control group (all P < 0.05) after 12 weeks of treatment.

Conclusion

TMS+CACT can effectively improve the intelligence level, cognitive ability, gross motor function, and cerebral blood flow of children suffering from cerebral palsy and intellectual disability.