Activity descending from the head ganglion. A. Diagram of the experimental preparation and set-up for recording activity descending from the head ganglion in the lateral connective. B. Approximately 2 sec before the onset of a spontaneous swim episode there is a large increase activity in the lateral connective. Note that this activity in the lateral connective stops abruptly prior to the end of the swim episode.

The length of the ventral nerve cord preparation was reduced by cutting the connective between segmental ganglion 1 and 2. In this new preparation few descending units in the lateral connective are active before the onset of a spontaneous swim episode.