Signal segmentation of ISH data. (a) Sagittal plane annotated drawing from Allen Reference Atlas containing the olfactory tubercle (OT), nucleus accumbens (ACB) and caudoputamen (above ACB). (b) Plane-matched colorimetric ISH data for the gene Drd1a. (c) Corresponding expression segmentation mask for the ISH image shown in (b). High expression is indicated by red and low expression by blue.