The F / F 0 response of WHaloCaMP1a expressed in cultured rat hippocampal neurons and labeled with the indicated dye-ligands to trains of APs. Solid line (mean) and gray outline (s.e.m.) for n = 153, 168 and 141 neurons for the JF 494 -HaloTag ligand, the JF 552 -HaloTag ligand and the JF 669 -HaloTag ligand and for n = 20 for the JF 722 -HaloTag ligand. Black arrows indicate the start of stimulation.
