Nor Zaihana Abdul RahmanRumelo AmorAlison McDonaldJohanna TrägårdhGillian RobbLouise WilsonJohn DempsterWilliam Bradshaw Amos1Trevor J. BushellGail McConnell2024-05-282024-05-2820161932-620310.1371/journal.pone.0147115https://oarep.usim.edu.my/handle/123456789/5846We demonstrate fluorescence imaging by two-photon excitation without scanning in biological specimens as previously described by Hwang and co-workers, but with an increased field size and with framing rates of up to 100 Hz. During recordings of synaptically-driven Ca2+ events in primary rat hippocampal neurone cultures loaded with the fluorescent Ca2+ indicator Fluo-4 AM, we have observed greatly reduced photo-bleaching in comparison with single-photon excitation. This method, which requires no costly additions to the microscope, promises to be useful for work where high time-resolution is required.en-USFluorescence imaging, Lasers, Optical lenses, Specimen sectioning,Two-photon excitation microscopy, Fluorescence, Fluorescence microscopy, Imaging techniquesArticle119