PT - JOURNAL ARTICLE AU - Steinmetz, Nicholas A. AU - Buetfering, Christina AU - Lecoq, Jerome AU - Lee, Christian R. AU - Peters, Andrew J. AU - Jacobs, Elina A. K. AU - Coen, Philip AU - Ollerenshaw, Douglas R. AU - Valley, Matthew T. AU - de Vries, Saskia E. J. AU - Garrett, Marina AU - Zhuang, Jun AU - Groblewski, Peter A. AU - Manavi, Sahar AU - Miles, Jesse AU - White, Casey AU - Lee, Eric AU - Griffin, Fiona AU - Larkin, Joshua D. AU - Roll, Kate AU - Cross, Sissy AU - Nguyen, Thuyanh V. AU - Larsen, Rachael AU - Pendergraft, Julie AU - Daigle, Tanya AU - Tasic, Bosiljka AU - Thompson, Carol L. AU - Waters, Jack AU - Olsen, Shawn AU - Margolis, David J. AU - Zeng, Hongkui AU - Hausser, Michael AU - Carandini, Matteo AU - Harris, Kenneth D. TI - Aberrant Cortical Activity in Multiple GCaMP6-Expressing Transgenic Mouse Lines AID - 10.1523/ENEURO.0207-17.2017 DP - 2017 Sep 01 TA - eneuro PG - ENEURO.0207-17.2017 VI - 4 IP - 5 4099 - http://www.eneuro.org/content/4/5/ENEURO.0207-17.2017.short 4100 - http://www.eneuro.org/content/4/5/ENEURO.0207-17.2017.full SO - eNeuro2017 Sep 01; 4 AB - Transgenic mouse lines are invaluable tools for neuroscience but, as with any technique, care must be taken to ensure that the tool itself does not unduly affect the system under study. Here we report aberrant electrical activity, similar to interictal spikes, and accompanying fluorescence events in some genotypes of transgenic mice expressing GCaMP6 genetically encoded calcium sensors. These epileptiform events have been observed particularly, but not exclusively, in mice with Emx1-Cre and Ai93 transgenes, of either sex, across multiple laboratories. The events occur at >0.1 Hz, are very large in amplitude (>1.0 mV local field potentials, >10% df/f widefield imaging signals), and typically cover large regions of cortex. Many properties of neuronal responses and behavior seem normal despite these events, although rare subjects exhibit overt generalized seizures. The underlying mechanisms of this phenomenon remain unclear, but we speculate about possible causes on the basis of diverse observations. We encourage researchers to be aware of these activity patterns while interpreting neuronal recordings from affected mouse lines and when considering which lines to study.