Figure 2.

GFP⁺ neurons near MEA electrodes. Three circles were drawn centered on each electrode, with diameters of respectively 70, 110, and 150 μm. The upper panels show a series of typical electrodes which showed no nearby GFP⁺ cells within 110 μm. In these cases, all the firing units were found to be of the AEN type. The lower panels show a series of electrodes displaying nearby GFP⁺ cells. In these, all the units were found to be of the AIN type. The plot on the right shows the cumulative probability of finding electrodes with GFP⁺ cells. The inset illustrates the corresponding count histogram obtained from 8 experiments and 1544 cells.