Stimulate trigger interneuron Signals from “front brain” (anterior ganglion) Signals to muscles Signals from “rear brain” (posterior ganglion)

Sometimes it swims... Signal to muscle Signals along ventral cord trigger Leech thinks it’s swimming

Sometimes not... No “swimming” signal trigger

For “triggered swim” signals variance increases. autocorrelation increases. greater predictability. “attractor” expands. Variance: no swim swim Autocorrelation: swim No swim Attractor size No swim swim predictability swim No swim