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Modulation of synaptically induced burst strength and spike onset timing by inactivating KIRcurrents in medium spiny neurons
© Steephen and Manchanda; licensee BioMed Central Ltd. 2008
Published: 11 July 2008
The membrane potential of striatal medium spiny neurons (MSNs) fluctuates between down- and up-states. In ventral striatum, inward rectifying potassium (KIR) currents in 40% of MSNs inactivate . The significance of this property is not clearly known. We describe a computational study investigating how synaptic integration is influenced by KIR current inactivation.
Two MSNs were modeled using NEURON, one equipped with non-inactivating KIR currents (henceforth, "Cell A") and the other with inactivating KIR currents (henceforth "Cell B") and their behaviors were compared in response to trains of inputs activating NMDA, AMPA and GABA synapses. Injected current inputs were then used to investigate the mechanisms underlying the observed differences.
Our model demonstrates the facilitatory effect of KIR current inactivation on MSN excitability in response to synaptic inputs. In view of the reports that dendritic intracellular calcium levels depend closely on burst strength as well as the spike onset time in MSNs , our findings suggest that KIR current inactivation may significantly modulate synaptic plasticity as well.
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