Those are two motorcortex neurons which express a specific type of virus which enables us to visualize them under a microscope. At this time, we were looking at expression patterns of retrograde HSV-GCaMP injections in the brain (Rat, striatum) after different timepoints, this was after 1 week of expression time and we wanted to see if there already is GCaMP expression in different areas of the brain from which we then could record. These two neurons would not have been enough to perform population-based optic fiber recordings (photometry) but were an indication that after 1 week retrograde expression from the striatum already reached the motorcortex. In this particular case I only took this image because of its surprising minimalistic charm.