Fig 2.

Temporal evolution of array wide firing rate (AWFR) in cultures exposed to hypoxia (pO₂≈20 mmHg) for 6 (A), 12 (B), 24 (C), or 48 hours (D), and 48 hours at pO₂≈80 mmHg (E). Filled background areas indicate the hypoxic period. All curves show a clear decrease of AWFR at the start of the hypoxic period followed by complete recovery after 6 or 12 hours. During longer hypoxic periods this initial decrease was followed by partial recovery up to ~18 hours. In four experiments, a few electrodes showed significantly increased activity and dominated AWFR (see text). Triangles indicate averages after removal of these outliers, circles show the average of all data. Error bars indicate SEM. Panel F shows the temporal development of AWFR in normoxic periods of 72 hours, recorded between 21 and 24 days after plating, as a control.