Fig. 5.

Synchrony among zooids. (A) Video recording showing synchronous oral siphon closure in three zooids in the same module in the absence of obvert stimulation (closure is shown downward). The colony was nearing takeover (stage A5). (B) Simultaneous electrical recordings from the brains of two mature zooids (stage A3) in a different module. The zooids were maximally distant from each other. Action potentials are seen to fire in bursts in the nervous systems of both zooids. (C) The second half of both records (t=150 to 250 s) are replotted at higher amplification to emphasize the firing patterns. Although the bursts are not strictly synchronous, there is strong similarity in timing and burst structure.