Proceedings of The Physiological Society

University of Central Lancashire (2002) J Physiol 543P, S220

Communications

Intrinsic variability in transmission at excitatory synapses between ocellar L-neurons in the locust, Schistocerca gregaria

Peter J. Simmons* and Rob de Ruyter van Steveninck†

*Department of Neuroscience, Newcastle University, Newcastle upon Tyne NE2 4HH, UK and †Lewis Thomas Laboratory, Princeton University, Princeton, NJ 08544, USA


Variation in the amount of neurotransmitter released from one trial to the next limits the reliability with which synapses transfer information. We have investigated this at an excitatory synapse made between two types of neuron in the ocellar system of the locust, Schistocerca gregaria. In the seven large second-order neurons of a lateral ocellus ('L-neurons'), small, graded changes in membrane potential convey information about changes in light and regulate release of neurotransmitter at output synapses. Small, rebound spikes, which are graded in amplitude, enhance responses to rapid decreases in light. Neurons L1

Where applicable, experiments conform with Society ethical requirements