Latency dependent development of related firing patterns of cultured cortical neurons

Networks of cortical neurons were grown over multi electrode arrays to enable simultaneous measurement of signals from multiple neurons. We described functional connectivity in these networks by relationships between individual electrodes, based on conditional firing probabilities. In this study we investigated periods in which the strength of a relationship monotonously increased (strengthening) or decreased (weakening) during periods of 24 or 10 hours. We observed a slightly increased incidence of latencies up to 25 ms during strengthening, while these latencies rarely occurreded during weakening. Next, it appeared that relationships tended to strengthen more than average in periods with latencies in the range 5-30 ms, whereas strengthening was significantly less than average in latencies 40-65 ms.