A computational model of synaptic transmission at the calyx of Held

The calyx of Held is a giant glutamatergic synapse in the mammalian auditory pathway designed to ensure faithful transmission of high frequency action potential trains. Preand postsynaptic recordings from this synapse reveal several forms of facilitation and depression. A computational model of synaptic transmission has been developed to investigate the mechanisms underlying modulation at the calyx of Held. The model includes paired-pulse facilitation and depression due to vesicle depletion and postsynaptic AMPA receptor desensitization. Accurately matching the experimental time course and magnitude of the depression requires both slow and fast replenishment of vesicles at the presynaptic release sites. The model demonstrates that the temporal accuracy of postsynaptic spike generation depends on the amplitude of the EPSC and so accuracy decreases as the EPSCs depress. 2001 Elsevier Science B.V. All rights reserved.