Electroporation efficiency using different electrode locations. (A) Schematic representation of the location of the electrodes used in the second part of this study. Only the positive pole is represented. Note the very ventral location of the tweezer-electrode cathode to target the lateral and septal wall of the lateral ventricle (LV), with no transfection of the dorsal wall. (B) Representative three-dimensional reconstruction illustrating the location and extent of the electroporated area after electroporation (EPO) with the electrode position shown in (A). Gray contours, brain; white contours, lateral ventricle; green contours, area containing electroporated cells. (C,D) Measurements of the electroporated area (C) and of the number of electroporated RGCs (D) obtained with the three electrode positions tested. Error bars represent standard error of the mean. *P < 0.05 as determined by unpaired t-test.