Short-term Synaptic Depression Improves Error-correcting Ability in Cortical Circuits

TL;DR

This paper proposes that short-term synaptic depression enhances error correction in cortical circuits by enlarging basins of attraction in associative memory models, without affecting storage capacity, through a combined theoretical and simulation approach.

Contribution

It introduces a new hypothesis that synaptic depression enlarges basins of attraction, improving error correction in cortical circuits, verified by mean-field theory and simulations.

Findings

Basins of attraction are enlarged by synaptic depression.

Storage capacity remains unchanged.

Synaptic depression and excitatory-inhibitory balance cooperate.

Abstract

Synaptic connections are known to change dynamically. High-frequency presynaptic inputs induce decrease of synaptic weights. This process is known as short-term synaptic depression. The synaptic depression controls a gain for presynaptic inputs. However, it remains a controversial issue what are functional roles of this gain control. We propose a new hypothesis that one of the functional roles is to enlarge basins of attraction. To verify this hypothesis, we employ a binary discrete-time associative memory model which consists of excitatory and inhibitory neurons. It is known that the excitatory-inhibitory balance controls an overall activity of the network. The synaptic depression might incorporate an activity control mechanism. Using a mean-field theory and computer simulations, we find that the basins of attraction are enlarged whereas the storage capacity does not change. Furthermore, the excitatory-inhibitory balance and the synaptic depression work cooperatively. This result suggests that the synaptic depression works to improve an error-correcting ability in cortical circuits.