Feedback activity is a significant component of the total conductance of the cell. In this significant paper, the authors analyze the activity of a neuron embedded in a paired feedback network.

The study was motivated by Murphy, et al. [1]. The authors examined the effects of paired delayed excitatory and inhibitory feedback on a single integrate-and-fire neuron with reversal potentials embedded within a feedback network. They employed bifurcation theory and numerical analysis to study the effects. The paper provides an extensive analysis of the possible dynamic behaviors of such simple but realistic neural loops as a function of the balance between positive and negative feedback, with and without noise, and offers insight into the potential behaviors such loops can exhibit in response to time-varying external inputs.

Laing and Longtin demonstrate how a biophysically plausible smoothing of the firing function can modify the existence and stability of the fixed points and oscillations of the system. Their results demonstrate that a paired delayed feedback can act as a sophisticated computational unit, capable of switching between a variety of behaviors, depending on the input current, the relative strengths and asymmetry of the two parallel feedback pathways, and the delay distributions and noise level.