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Simulation of spike timing dependent synaptic plasticity induced by spike triplets with stochastic transmitter release
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Y. Cai1*; J. Gavornik1,2; H.Z. Shouval1,2
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1. Dept Neurobiol Anat, Univ Texas Houston Med Sch, Houston, TX, USA 2.
Dept Biomed Eng, Univ Texas Austin, Austin, TX, USA |
Experimental results indicate that synaptic plasticity produced by
multi spike protocols cannot be accounted for by linear superposition
of synaptic plasticity produced by spike pairs (Froemke and Dan , 2002;
Wang et al., 2005). We have postulated that our previously published
(Shouval et. al., 2002) plasticity model, together with realistic
assumptions about cellular and synaptic dynamics such as paired pulse
depression can account for these multi spike induction protocols. When
applied to plasticity of layer 4 to layer 2/3 neurons of visual cortex
the model preformed well, except for the post-pre-pre region in which
the model predicted potentiation while the experimental results
predicted depression. Moreover, this qualified sucsess may not
generalize well to synaptic pathways that exhibit paired pulse
facilitation (e.g. Hippocampal neurons).
Models previously applied for multi spike plasticity, while taking
into account detailed properties of synaptic and cellular dynamics, do
not take into account the stochastic nature of synaptic transmission.
In the present work, we implemented stochastic transmitter release in
the presynaptic neuron as well as the depletion of readily available
neurotransmitter responsible for paired pulse depression. This
stochastic model has average synaptic dynamics that are identical to
the deterministic model. However, the stochastic model, by adandoning
the simplified deterministic approximation, is able to replicate
experimental data in all regions. We are currently applying thesed
ideas to synapses that exhibit paired pulse facilitation as well.
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Citation for this abstract:
Cai, Y., J. Gavornik, H.Z. Shouval (2005). Simulation of spike timing dependent plasticity induced by spike triplets with stochastic transmitter release. Soc. Neurosci. Abstr.
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