title: Upregulation of transmitter release probability improves a conversion of synaptic analogue signals into neuronal digital spikes.
abstract: Action potentials at the neurons and graded signals at the synapses are primary codes in the brain. In terms of their functional interaction, the studies were focused on the influence of presynaptic spike patterns on synaptic activities. How the synapse dynamics quantitatively regulates the encoding of postsynaptic digital spikes remains unclear. We investigated this question at unitary glutamatergic synapses on cortical GABAergic neurons, especially the quantitative influences of release probability on synapse dynamics and neuronal encoding. Glutamate release probability and synaptic strength are proportionally upregulated by presynaptic sequential spikes. The upregulation of release probability and the efficiency of probability-driven synaptic facilitation are strengthened by elevating presynaptic spike frequency and Ca2+. The upregulation of release probability improves spike capacity and timing precision at postsynaptic neuron. These results suggest that the upregulation of presynaptic glutamate release facilitates a conversion of synaptic analogue signals into digital spikes in postsynaptic neurons, i.e., a functional compatibility between presynaptic and postsynaptic partners.
authors.affiliation: State Key Lab for Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China 100101.
authors.forename: Jiandong
authors.initials: J
authors.lastname: Yu
authors.forename: Hao
authors.initials: H
authors.lastname: Qian
authors.forename: Jin-Hui
authors.initials: JH
authors.lastname: Wang
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D003198:Computer Simulation; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D059330:GABAergic Neurons / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D051379:Mice; D009474:Neurons / Q000502:physiology*; D018377:Neurotransmitter Agents / Q000378:metabolism*; D017729:Presynaptic Terminals / Q000378:metabolism; D015398:Signal Transduction; D013569:Synapses / Q000378:metabolism*; D009435:Synaptic Transmission; D015854:Up-Regulation
chemical_list: D018377:Neurotransmitter Agents; D018698:Glutamic Acid; D004533:Egtazic Acid; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D002118:Calcium