In a collaborative work with Pr. Avrama Blackwell (George Mason University, the Krasnow Institute for Advanced Study, Fairfax, USA), Yihui Cui contributed to a recent study on a new model of the dorsal striatum. Thanks to a multi-compartmental biophysical model of a dorsal striatal MSN, they were able to investigate the role of GluN2 subunit on spine calcium concentration during STDP protocols. They found that in NMDA-dependent LTP, the postsynaptic calcium elevation triggered by STDP protocol is dependent on multiple factors. These factors include GluN2 subunits, spike-timing, duration of somatic depolarization (30 vs. 5ms), dendritic location of synapses and number of spikes. Simulation showed the dendritic location of thalamostriatal (more distal) and corticostriatal synapses is the sole factor that creates a different picture of STDP in these two synapses. Due to the more proximal dendritic location and a consequent faster and stronger back-propagation of the AP, the STDP protocol triggers a stronger calcium elevation in corticostriatal synapses than in thalamostriatal synapses. Therefore, the thalamostriatal synapses exhibit a more restrict temporal window for STDP-LTP induction than corticostriatal synapses. Find more details in the article:
Evans RC, Morera-Herreras T, Cui Y, Du K, Sheehan T, Kotaleski JH, Venance L, Blackwell KT. The effects of NMDA subunit composition on calcium influx and spike timing-dependent plasticity in striatal medium spiny neurons. PLoS Comput Biol. 2012. 8(4): e1002493.
Keywords: NMDA receptors,Long-term potentiation,Spike timing dependent plasticity,Calcium influx,GluN2 subunits.
Figure 1C from Evans et al., PLoS One, 2014. Comparison of the model simulated medium spiny neuron and experimentally measured medium spiny neuron inward rectification (-50 pA to 200 pA).