The role of background synaptic noise in striatal fast spiking interneurons

Striatal fast spiking (FS) interneurons provide inhibition to each other as well as to medium spiny projection (SP) neurons. They exhibit up-states synchronously with SP neurons, and receive GABAergic and AMPA synaptic input during both up- and down-states. The synaptic input during down-states can be considered noise and might affect detection of up-states. We investigate what role this background noise might play for up-state firing in a 127 compartment FS model neuron. The model has Na, KDr and KA conductances, and is activated through AMPA and GABA synapses. The model's response to current injection and synaptic inputs resembled experimental data. We show that intermediate levels of noise neither facilitates nor degrades the ability of the FS neuron model to detect up-states.