Seventy-two hours post-infection (hpi), the cultures were fixed and examined by confocal fluorescence microscopy, revealing the presence of fused neurons [positive for the neuronal marker microtubule-associated protein 2 (MAP2)], as characterized by the presence of both the GFP and mCherry fluorescent proteins for all the SARS-CoV-2 titers used (Fig. 1, B and C). Here, MAP2 is linked to infection.