@article {SteinmetzENEURO.0207-17.2017, author = {Nicholas A. Steinmetz and Christina Buetfering and Jerome Lecoq and Christian R. Lee and Andrew J. Peters and Elina A. K. Jacobs and Philip Coen and Douglas R. Ollerenshaw and Matthew T. Valley and Saskia E. J. de Vries and Marina Garrett and Jun Zhuang and Peter A. Groblewski and Sahar Manavi and Jesse Miles and Casey White and Eric Lee and Fiona Griffin and Joshua D. Larkin and Kate Roll and Sissy Cross and Thuyanh V. Nguyen and Rachael Larsen and Julie Pendergraft and Tanya Daigle and Bosiljka Tasic and Carol L. Thompson and Jack Waters and Shawn Olsen and David J. Margolis and Hongkui Zeng and Michael Hausser and Matteo Carandini and Kenneth D. Harris}, title = {Aberrant Cortical Activity in Multiple GCaMP6-Expressing Transgenic Mouse Lines}, volume = {4}, number = {5}, elocation-id = {ENEURO.0207-17.2017}, year = {2017}, doi = {10.1523/ENEURO.0207-17.2017}, publisher = {Society for Neuroscience}, abstract = {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.}, URL = {https://www.eneuro.org/content/4/5/ENEURO.0207-17.2017}, eprint = {https://www.eneuro.org/content/4/5/ENEURO.0207-17.2017.full.pdf}, journal = {eNeuro} }