Corrigendum: Imaging Calcium in Hippocampal Presynaptic Terminals With a Ratiometric Calcium Sensor in a Novel Transgenic Mouse - Al-Osta, Ibrahim; Mucha, Mariusz; Pereda, Daniel; Piqué-Gili, Marta; Okorocha, Albert E.; Thomas, Roisin; Hartell, Nicholas A. (Frontiers in Cellular Neuroscience, 2019)