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. 2016 May 27;6:25777. doi: 10.1038/srep25777

Figure 3. Morphology and activity of cultured networks on MEAs.

Figure 3

(a) Phase contrast microscopy images from selected controls and F22-treated networks on MEAs from 3 to 22 DIV. For each DIV, a magnified view of the whole network (upper left inset) shows the neurons on and around the four central MEA electrodes (Ø30 μm, 200 μm pitch). (b) Raw signals recorded from individual electrodes. Each row represents a five seconds activity window of one electrode at different DIVs. Black arrows point out single spikes and red arrows burst activity. The top row depicts activity recorded from a control culture. The bottom trace was selected from the F22-treated group. F22 clearly shows the appearance of both individual spikes and burst activity at 6 DIV. Spike amplitude ≥100 μV. (c) Immunofluorescence images prepared from control and F22-treated cultures at 22 DIV. Each row represents a selected sample from one group. The first four columns show the immunofluorescence images merged with the phase contrast images. Left to right: DAPI, DAPI/ β-tubulin III, DAPI/GFAP, DAPI/β-tubulin III/GFAP (scale bar; 200 μm). (d) Average spike frequency and number of active channels. The spike frequency is the mean number of spikes per second recorded from every active electrode in the control or F22-treated cultures, respectively. The mean spike rate was calculated by averaging the mean spike frequency over all active channels in one group. Channels were considered active if they showed ≥3 spikes per minute. Solid lines with circular markers represent the mean ± SEM spike rate, whereas the shaded areas quantify the mean number of active channels in every culture of the control or F22-treated groups on the respective DIV. (e) Average burst rate and mean number of electrodes, which showed burst activity. The burst rate is the mean number of bursts per minute recorded on active electrodes in control or F22-treated cultures, respectively. Channels which showed at least 1 burst per minute were considered active channels. Solid lines with circular marks represent average burst rates, whereas the surfaces represent the mean number of active channels in every control or F22-treated cultures on the respective DIV.