Possible efference to the ocellar system of the locust and its effect on ocellar interneurons

Abstract

1. Some units in the lateral ocellar nerves of the locust,Locusta migratoria, are influenced transsynaptically by the activity of ascending fibres in the thoracic connectives and therefore may be efferent to the afferent ocellar system. 2. A variety of sensory inputs excite the ocellar nerve units, including illumination of the compound eyes, active and passive movement of the wings, wind stimuli to the thorax and sound. 3. Most ocellar interneurons are influenced transsynaptically by electrical stimulation of the cervical connectives. L-neurons are depolarized and the components of their response to a rectangular light pulse are changed in amplitude. Only a few S-neurons could be examined. All of them were excited directly or indirectly. 4. The descending ocellar interneurons (DN's) are influenced by stimulation of the contralateral connective, perhaps via efference to the ocellus or to ocellar L-cells.