Stroke, a significant global cause of death and disability, results in long-term impairments encompassing a wide range of motor deficits and enduring cognitive challenges. The ongoing degenerative mechanisms following a stroke affect not only the primary infarct region but also remote regions and white matter (WM) tracts. These tracts are connected to the primary infarct site but were not initially damaged by the stroke. This phenomenon is referred to as secondary neurodegeneration (SND) and has been characterized in fiber tracts such as the cerebrospinal tract (CST).
Previous studies report a relationship between decreased anisotropy in the ipsilesional CST and the severity of motor impairment post-stroke. As decreased anisotropy is a sign of SND, these findings highlight the importance and influence of SND on motor recovery. Thus, anisotropy could be a promising biomarker for motor recovery post-stroke.
In this study, we induced cortical ischemic stroke by photothrombosis in the left sensorimotor cortex of adult C57BL/6J mice. After collecting dMRI data of the mice at different time points after stroke, we visualize specific WM tracts such as the CST and the corpus callosum (CC) with Diffusion Tensor Imaging (DTI) in the program DSI-Studio. We can then calculate diffusion metrics such as fractional anisotropy (FA), which can reveal axonal changes. Comparing these parameters, we aim to characterize SND in selected WM tracts after stroke. One focus is on identifying a correlation between the time past the stroke and the extent of SND, as well as a correlation between SND and motor impairment or stroke recovery.
