Quantifying Transfected Cells in Mouse Brain

A VS120-S6-W Virtual Slide Scanner (Olympus; Tokyo, Japan) was used to scan all the sections. Images were taken with a color camera (Nikon DS-Fi3; Tokyo, Japan). To reduce bias, the photomicrography and counting were performed by a blinded researcher. Image J (version 1.41; National Institutes of Health, Bethesda, MD) was used for cell counting and Canvas software (ACD Systems, Victoria, Canada, v. 9.0) was used for line drawings. A one-in-two series of 25-μm brain sections was used per mouse, such that each section analyzed was 50 μm apart. The area analyzed was delimited (mean of 5,423 μm²) based on previous data (Anderson et al., 2016 (link)). Sections were examined to confirm the number of transfected cells. The number of labeled cells were bilaterally counted and reported as median ± interquartile range (IQR). Section alignment was relative to a reference section, as previously described (Anderson et al., 2016 (link)) and based on the Paxinos and Franklin atlas (Paxinos and Franklin, 2012 ).