A Day in The Lab: Investigating Calcium Activity in the White Matter

🕒 Approximate reading time: 3 minutes

Today's activities in the lab were directed at the in-depth analysis of calcium activity in the white matter located within the corpus callosum, the region of the brain bridging the two hemispheres. The process engaged recordings of the brain obtained through a 2-photon microscope. A red fluorescent dye enabled the visualisation of blood vessels, while a green fluorescent dye highlighted the white matter (essentially, the oligodendrocytes encircling the neurons). The purpose of this study was to scrutinise the spontaneous calcium activity within the white matter, a venture that was unprecedented. This task necessitated significant coding via Matlab and a host of complex mathematical functions to extract pertinent information from the microscopic recordings.

Here's an example of what the actual recordings appeared like under the microscope.

An Insight into Today's Experimental Procedures

The experiment involved the employment of a genetically-encoded calcium indicator in oligodendrocytes, facilitating the recording of calcium activity in myelin in vivo. This was achieved using 2-photon imaging, via a cranial window fitted over the corpus callosum. Computer code was then employed to identify individual oligodendrocytes and extract their basal calcium activity. This data was then compared under different conditions (3 weeks post-surgery, 5 weeks post-surgery, during locomotion, and at rest). An array of mathematical functions, such as Principal Component Analysis (PCA) and Independent Component Analysis (ICA), were utilised for data analysis. These functions were crucial for extracting cellular signals from the imaging datasets and for computing the firing rate of the cells.