Neural mechanisms underlying behavior in the locust Schistocerca gregaria. II. Integrative activity in metathoracic neurons

Preliminary studies are reported on the roles of some interneurons and motorneurons in generating simple behavior patterns in the locust Schistocerca gregaria. The neurons were penetrated by intracellular electrodes singly, or in pairs, whilst a variety of reflexes and spontaneous movements was observed. For example: large oscillations of membrane potential occurring at characteristic flight frequency were observed in flight motorneurons after blowing on the head. The pattern of impulses was directly determined by the amplitude and period of the oscillations. Similar oscillations were observed to occur spontaneously in leg motorneurons, where they caused bursts of impulses which closely resembled those occurring during walking. Both sensory‐integrating and pre‐motor interneurons were encountered, but none with the function of “commanding” motor output. Much of the input to leg motorneurons is already in programmed form.