Synaptic connections between medial giant neurons in lobsters

Abstract

1. 1. Synaptic connections between the pair of medial giant (MG) interneurons were found in the supraesophageal ganglion (brain) of the lobster. Transmission at this connection appears to be mediated via a two-way electrical synapse. 2. 2. A posterior connection between the MGs, in one or more abdominal ganglia, was also observed. Conduction at the posterior synapse was usually observed after blocking of the anterior synapse. 3. 3. In some cases, transmission at the posterior connection was one-way. This resulted in a “reverberating circuit” with an action potential traveling around the nervous system for several circuits in the MGs. 4. 4. Mode of transmission in this posterior synapse is unknown but may occur through neural elements which receive common input from the MGs.