Bursts shape the NMDA-R mediated spike timing dependent plasticity curve: role of burst interspike interval and GABA inhibition

Cutsuridis, Vassilis (2012) Bursts shape the NMDA-R mediated spike timing dependent plasticity curve: role of burst interspike interval and GABA inhibition. Cognitive Neurodynamics, 6 (5). pp. 421-441. ISSN 1871-4080

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Abstract

Spike timing dependent plasticity (STDP) is a
synaptic learning rule where the relative timing between
the presynaptic and postsynaptic action potentials determines
the sign and strength of synaptic plasticity. In its
basic form STDP has an asymmetric form which incorporates
both persistent increases and persistent decreases in
synaptic strength. The basic form of STDP, however, is not
a fixed property and depends on the dendritic location. An
asymmetric curve is observed in the distal dendrites,
whereas a symmetrical one is observed in the proximal
ones. A recent computational study has shown that the
transition from the asymmetry to symmetry is due to
inhibition under certain conditions. Synapses have also
been observed to be unreliable at generating plasticity
when excitatory postsynaptic potentials and single spikes
are paired at low frequencies. Bursts of spikes, however,
are reliably signaled because transmitter release is facilitated.
This article presents a two-compartment model of the
CA1 pyramidal cell. The model is neurophysiologically
plausible with its dynamics resulting from the interplay of
many ionic and synaptic currents. Plasticity is measured by
a deterministic Ca2? dynamics model which measures the
instantaneous calcium level and its time course in the
dendrite and change the strength of the synapse accordingly.
The model is validated to match the asymmetrical
form of STDP from the pairing of a presynaptic (dendritic)
and postsynaptic (somatic) spikes as observed experimentally.
With the parameter set unchanged the model investigates
how pairing of bursts with single spikes and bursts
in the presence or absence of inhibition shapes the STDP
curve. The model predicts that inhibition strength and
frequency are not the only factors of the asymmetryto-
symmetry switch of the STDP curve. Burst interspike
interval is another factor. This study is an important first
step towards understanding how STDP is affected under
natural firing patterns in vivo.

Keywords:Computer model, Calcium, Theta burst, Inhibition, Backpropagating action potential, NMDA
Subjects:B Subjects allied to Medicine > B140 Neuroscience
G Mathematical and Computer Sciences > G730 Neural Computing
Divisions:College of Science > School of Computer Science
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ID Code:27716
Deposited On:05 Jul 2017 09:09

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