ABA ISH data repeatability. A scatter plot is shown for the average level (x-axis) and density (y-axis) measurements over a multi-day and multi-probe data set. For each of 9 genes (Calb1, Calb2, Cst3, Dkk3, Gad1, Man1a, Plp1, Pvalb, and Nov), 16 repeated measurements of expression level [0,255] and density [0,100] for an entire brain hemisphere are plotted. Probes were independently generated by in vitro transcription four times on four different days. Each independently synthesized probe was hybridized to brain tissue sections over a span of four days.