Frequency-Dependent Changes in NMDAR-Dependent Synaptic Plasticity | Kumar Mehta 2011Frontiers in Computational Neuroscience

<p>Nov 07, 2011 08:09 PM

&#160;

Kumar and Mehta &#160;Sept 2011 &#160;article is <b>open acces</b>s

in Front in Comput Neuroscience

&#160;

important paper... &#160;pdf is abt 1.5 mb . &#160;

&#160;

The NMDAR-dependent synaptic plasticity is thought to mediate several forms of learning, and can be induced by spike trains containing a <b>small number of spikes occurring with varying rates and timing</b>, as well as with oscillations.&#160;

&#160;

We computed the influence of these variables on <b>the plasticity induced at a single NMDAR containing synapse</b> using a reduced model that was analytically tractable, and these findings were confirmed using detailed, multi-compartment model.

&#160;

&#160;

&#160;In addition to explaining diverse experimental results about the rate and timing dependence of synaptic plasticity, the model made several novel and testable predictions. We found that there was a<b> preferred frequency for inducing long-term potentiation (LTP) such that higher frequency stimuli induced lesser LTP</b>, decreasing as 1/<i>f</i> when the number of spikes in the stimulus was kept fixed. Among other things,&#160;

&#160;

the <b>preferred frequency for inducing LTP varied as a function of the distance of the synapse from the soma</b>.&#160;

&#160;

In fact, same <b>stimulation frequencies could induce LTP or long-term depression depending on the dendritic location </b>of the synapse. Next, we found that <b>rhythmic stimuli induced greater plasticity then irregular stimuli</b>. Furthermore, <b>brief bursts of spikes significantly expanded the timing dependence of plasticity.</b> Finally, we found that in the<b> ∼5–15-Hz frequency range both rate- and timing-dependent plasticity mechanisms work synergistically to render the synaptic plasticity most sensitive to spike timing.</b> These findings provide computational evidence that <b>oscillations can have a profound influence on the plasticity of an NMDAR-dependent synapse</b>, and show a novel role for the dendritic morphology in this process.</p>