To begin identifying potential dynamically-defined computational elements within the striatum, we constructed a new three-dimensional model of the striatal microcircuit's connectivity, and instantiated this with our dopamine-modulated neuron models of the MSNs and FSIs. A new model of gap junctions between the FSIs was introduced and tuned to experimental data. We introduced a novel multiple spike-train analysis method, and apply this to the outputs of the model to find groups of synchronised neurons at multiple time-scales. We found that, with realistic in vivo background input, small assemblies of synchronised MSNs spontaneously appeared, consistent with experimental observations, and that the number of assemblies and the time-scale of synchronisation was strongly dependent on the simulated concentration of dopamine. We also showed that feed-forward inhibition from the FSIs counter-intuitively increases the firing rate of the MSNs.
Model Type: Realistic Network; Neuron or other electrically excitable cell
Cell Type(s): Neostriatum fast spiking interneuron
Receptors: D1; D2; GabaA; AMPA; NMDA; Dopaminergic Receptor
Transmitters: Dopamine; Gaba; Glutamate
Model Concept(s): Activity Patterns; Temporal Pattern Generation; Synchronization; Spatio-temporal Activity Patterns; Parkinson's; Action Selection/Decision Making; Connectivity matrix
Simulation Environment: MATLAB
Implementer(s): Humphries, Mark D [m.d.humphries at shef.ac.uk]; Wood, Ric [ric.wood at shef.ac.uk]
References:
Humphries MD, Wood R, Gurney K. (2009). Dopamine-modulated dynamic cell assemblies generated by the GABAergic striatal microcircuit. Neural networks : the official journal of the International Neural Network Society. 22 [PubMed]