The activity of NKCC1 regulates the migration speed of RMS neuroblasts. (A) Plot showing the average migration speed of neuroblasts during a 3 hour recording session. Three groups are plotted: control (transduced with a control non-target shRNA sequence), bumetanide (transduced with a control non-target shRNA sequence and incubated in 10 μM bumetanide), and shNKCC1 (transduced with shNKCC1). (B) Photomicrograph of tangentially migrating GFP+ neuroblasts in the RMS. The RMS was aligned horizontally so that changes along the x-axis represent displacement towards or away from the OB. Scale bar: 100 μm. Insets: detail of the directionality of the leading process in migrating neuroblasts. Scale bars: 10 μm. (C) Analysis of the migration directionality during the experimental session in the groups of cells described in (A). Displacement towards the SVZ is given a negative value whereas movements towards the OB are positive. Each point represents the total distance covered by one cell during the experimental session and the cells' initial position is at the origin. A red diamond represents the median value for each group. For this and the following figures *P < 0.05 and **P < 0.01.