Fig. 7.

Neuronal and behavioral responses to repeated focal stimulation. (A) A 10 ms water jet from a glass micropipette was used to stimulate a module of zooids while recording from the brains of two of them (A and B). The water jet was pointed at a third zooid (leftmost pipette in the photo). Stimulus timing is shown in D and the resulting closure of one of the oral siphons is shown in C. Each stimulus elicits a sustained burst of action potentials that begins before the siphon contraction. The burst pattern at the beginning of the response to the first stimulus in B is shown on an expanded time scale in E to illustrate the complicated burst structure.