Fig. 2

Characterization of WHaloCaMP1a in neuronal cultures.

a, Representative images of cultured rat hippocampal neurons expressing WHaloCaMP1a labeled with dye-ligands unstimulated or stimulated with 160 induced APs. Scale bars, 50 µm. Stim., stimulation. b, The ∆F/F₀ 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 JF₄₉₄-HaloTag ligand, the JF₅₅₂-HaloTag ligand and the JF₆₆₉-HaloTag ligand and for n = 20 for the JF₇₂₂-HaloTag ligand. Black arrows indicate the start of stimulation. c, Peak ∆F/F₀ as a function of the number of APs. Data are presented as mean and s.e.m. for n = 153, 168 and 141 neurons for the JF₄₉₄-HaloTag ligand, the JF₅₅₂-HaloTag ligand and the JF₆₆₉-HaloTag ligand and for n = 20 for the JF₇₂₂-HaloTag ligand. APs were elicited with a field stimulation electrode with a pulse width of 1 ms at 80 Hz and 40 V.