... We show that a transient potassium (KA) current allows the Fast Spiking (FS) interneuron to strike a balance between sensitivity to correlated input and robustness to noise, thereby increasing its signal-to-noise ratio (SNR). First, a compartmental FS neuron model was created to match experimental data from striatal FS interneurons in cortex–striatum–substantia nigra organotypic cultures. Densities of sodium, delayed rectifier, and KA channels were optimized to replicate responses to somatic current injection. Spontaneous AMPA and GABA synaptic currents were adjusted to the experimentally measured amplitude, rise time, and interevent interval histograms. Second, two additional adjustments were required to emulate the remaining experimental observations. GABA channels were localized closer to the soma than AMPA channels to match the synaptic population reversal potential. Correlation among inputs was required to produce the observed firing rate during up-states. In this final model, KA channels were essential for suppressing down-state spikes while allowing reliable spike generation during up-states. ... Our results suggest that KA channels allow FS interneurons to operate without a decrease in SNR during conditions of increased dopamine, as occurs in response to reward or anticipated reward. See paper for more and details.
Model Type: Neuron or other electrically excitable cell
Region(s) or Organism(s): Striatum
Currents: I Na,t; I A; I K; I Potassium
Model Concept(s): Activity Patterns; Ion Channel Kinetics; Parameter Fitting; Detailed Neuronal Models; Parkinson's
Simulation Environment: GENESIS
Implementer(s): Blackwell, Avrama [avrama at gmu.edu]; Kotaleski, Jeanette [jeanette at csc.kth.se]
References:
Kotaleski JH, Plenz D, Blackwell KT. (2006). Using potassium currents to solve signal-to-noise problems in inhibitory feedforward networks of the striatum. Journal of neurophysiology. 95 [PubMed]