I did FISH on a vibratome hippocampus section for locating circHomer1. According to other journals, circHomer1 should be expressed in the cell bodies and thus the signals might be overlapped with that of DAPI in granular cell layer. My results, however, was found vey limited signal on granular cell layer but obviously seen on stratum oriens and stratum radiatum. I did a no probe negative control and no signal found so I assumed these might be the real signal but just so weird. May I please seek some idea about what these signals are and how to troubleshoot it?