Mechanoresponsive neurones in the suboesophageal ganglion of the locust


*Department of Zoology and University Museum, University of Oxford, South Parks Road, Oxford OX1 3PS.


Abstract. A preparation is described for intracellular recording from the neur-opile of the sub-oesophageal ganglion (SOG) of the locust, while stimulating the labial and maxillary palps with plant material in such a way as to mimic the palpation behaviour which precedes and continues throughout feeding. Twelve neurones responding to simulated palpation were recorded from and stained in the SOG. Axons of three neurones ascended to the brain, six had descending axons and three had all of their processes confined to the suboesophageal ganglion. The major regions of arborization were in the ventrolateral and mediolateral neuropiles of the maxillary and labial neuromeres. All twelve neurones were solely mechanoresponsive. In addition to responding to palpation of one or more of the four palps, five also responded to stimulation of the labrum, one to touching each antenna, and one to mechanical stimulation of each of the six tarsi. In the context of what is known about the role of mechano-stimulation in the control of feeding, and given their particular patterns of input and arborizations, it is suggested that the neurones may be active during food selection and ingestion.