Cortical Cultures Exhibit An Extremely Rich Repertoire of Bursting Patterns
35th Annual Meeting of the Society for Neuroscience, Washington, DC, 2005. Prog. no. 249.14
We have collected the most comprehensive set to date of multiunit data on dissociated cortical cultures. We followed the first five weeks of the development of 58 cultures of different densities—3000 to 50,000 neurons on 30 to 75 mm2—growing on micro-electrode arrays (MEAs). While the aggregate spike detection rate scaled linearly with density—as expected from the number of cells in proximity to electrodes—dense cultures started to exhibit bursting behavior earlier in development than sparser cultures. Analysis of responses to electrical stimulation suggests that axonal outgrowth likewise occurred faster in dense cultures. After two weeks, the networks’ activity was dominated by population bursts in most cultures. In contrast to previous reports, development continued with changing burst patterns throughout the observation period. Burst patterns were extremely varied, with interburst intervals between 1 and 300 s, different amounts of temporal clustering of bursts, and different firing rate profiles during bursts.
These results are founded on a database consisting of 966 half-hour-long recordings from 58 cultures from 8 plating batches. To encourage more investigation of the rich range of behaviors exhibited by cortical cells in vitro, we are making it available to other researchers in its entirety, together with matlab code to facilitate access.