Simultaneous optical recording of activity from many neurons during feeding in Navanax.

Optical methods for monitoring changes in membrane potential have been used to measure action potential activity in the buccal ganglion of an opisthobranch mollusc, Navanax inermis, while the animal was feeding. During feeding activity was detected in 10-15% of the approximately 200 neurons present in the ganglion. Control experiments carried out to determine the completeness of the optical recording showed that activity in at least 70% of the neurons could be detected. Thus, in certain invertebrate ganglia, it is possible to make a reasonably complete recording of the neuron activity responsible for generating relatively complex behaviors.