Population response in autaptic and disynaptic inhibitory cortical microcircuitry: a computational study

The dynamic of the neuronal response is highly influenced by the nature and the amount of noise that a neuron experienced, this noise being either external and internal to the neuron. The 10 000 synaptic afferents may not fire synchronously, hence, cause the synaptic noise, and ion channels are intrinsically noisy. Recent discoveries at the cellular- and microcircuit-levels describing several stereotypical pathways were reported, such as target-specific homosynaptic plasticity, disynaptic inhibition between pyramidal neurons, and differential self-inhibition of interneurons. This study proposes a large exploration of neuronal dynamical response properties, and describes how they are affected by these features. In particular, the introduction of heterogeneity in the dynamic of sodium channels affects the filtering behavior of the neuronal response, whereas inhibitory autapses seem to have less impact on the dynamic. However, autapses may have an important role for enhancing the spike time reliability by reducing the intrinsic channel noise, allowing the timing precision relevant to several behaviors, as suggest simulations of simple microcircuitry architectures and neocortical slice recordings