Figure 6.

Dose-dependent bursting properties of MEA neuron cultures over time. MEA electrode burst analyses were performed for non-lethal MIRB dosages of 0 µg/ml, 5 µg/ml, and 10 µg/ml, at time points of 0 h (pretreatment; ~ 1 h prior to MIRB addition), and 4, 24, and 48 h subsequent to MIRB addition. (a) Total number of bursting electrodes, normalized to the total number of bursting electrodes at 0 h (pretreatment). For this burst analyses performed with 0 (control), 5, and 10 µg/ml MIRB nanoparticles, 57%, 73% and 47% of the active electrodes were bursting electrodes (> 1 burst / min and < 51 spikes per burst) per MEA on average at pretreatment, respectively. (b) Mean burst duration. (c) Mean number of spikes per burst was not systematically affected by MIRB dosages up to 10 µg/ml. (d) Mean burst rate. Error bars denote Poisson counting errors in (a) and the standard errors of the means in (b), (c), and (d). For the mean burst duration in (b), the p-values relative to the control (p₅, p₁₀), for 5 and 10 µg/ml respectively, were (0.004, 0.094), (0.994, 0.872), (0.540, 0.757), and (0.013, 0.997) for 0, 4, 24, and 48 h respectively. With the same notation, for the mean spikes per burst in (c), the p-values were (0.932, 0.022), (0.528, 0.982), (0.889, 0.955), and (0.994, 0.976). The p-values for the mean burst rate were (0.412, 0.175), (0.093, 0.987), (0.0003, 0.967), and (0.082, 0.770).