Nonlinearity in simple phenomenological model for activity-dependent responses of target-cell specific synapses

抄録

Synaptic responses in activity-dependent manners are thought to play crucial roles in neuronal information processing and are called short-term synaptic plasticity. Typically, two major types of short-term plasticity are observed in the cortical or the hippocampal synapses: facilitation and depression. Although these synaptic responses are reproducible in a canonical phenomenological model, synaptic responses are diverse and target-cell specific, and then the phenomenological model does not cover synaptic responses such as facilitation growth and facilitation-depression. In contrast, while detailed models of short-term plasticity can trace the two synaptic responses, its computational costs are too heavy to simulate large-scale neuronal networks whose simulations are necessary to clarify functional roles and mechanisms of information processing in the cortical or the hippocampal fine-scale circuits. To understand them, the realization of the synaptic responses by a simple STP model is an important issue. In the current study, it is demonstrated a small extension of the canonical phenomenological model makes it possible to realize the synaptic responses of the facilitation growth and the facilitation-depression. Besides, the current study conducts basic analyses of responses in the synapses to both regular and random action potential trains and provides results of the analyses because the nature of the synapses is not clarified yet.