Figure 1. AMPAergic blockade reduces burst frequency and overall spike rate.

(A) Network bursts can be identified by detected spikes (red dots) time-locked in multiple channels of the multi-electrode array (MEA) (Y axis). One burst (red rectangle) is expanded in time and shown in the raster plot on the right. (B) The normalized burst rate is shown in control cultures and following application of CNQX for 24 hr. (C) Average overall spike frequency is compared for CNQX-treated cultures and control unstimulated cultures at 1 hr, 3 hr, 6 hr (p=0.104), and 24 hr (p=0.982) after addition of CNQX or vehicle. The mean differences at different time points are compared to control and displayed in Cumming estimation plots. Significant differences denoted by *p≤0.05, **p≤0.01, ***p≤0.001. Recordings from single cultures (filled circles, control n=3 cultures, CNQX n=8 cultures), where mean values (represented by the gap in the vertical bar) and SD (vertical bars) are plotted on the upper panels. Mean differences between control and treated groups are plotted on the bottom panel, as a bootstrap sampling distribution (mean difference is represented by a filled circles and the 95% CIs are depicted by vertical error bars).

Figure 1—figure supplement 1. Custom-written MATLAB program identifies bursts in cortical cultures plated on multi-electrode arrays (MEAs) by choosing the minimum number of spikes per burst (Spikes/Burst) across a minimum number of channels contributing to a burst (Min channels) within a maximum Time Window.

Upper image shows the identification of bursts in red across 64 channels as a raster plot where each dot represents one spike detected on the MEA. The program then examines various parameters which were then exported to an excel spreadsheet for analysis. Burst identity and duration are shown as a red line positioned below the raster plot. A single burst is expanded and plotted below the upper image.

Figure 1—figure supplement 2. Rasterplot of cortical culture plated on multi-electrode array (MEA) demonstrating network bursting (red dots, upper plot).

Bursts were then abolished after addition of TTX (1 µM) to the culture; a small number of spike detections remain, however these are likely to be noise that crosses the detection threshold.