Fluctuation in background synaptic activity controls synaptic plasticity

TL;DR

This paper investigates how fluctuations in background synaptic activity influence synaptic plasticity, revealing that increased fluctuation enhances LTP likelihood and affects synaptic weight, with implications for learning and memory.

Contribution

It provides a novel numerical analysis linking background activity fluctuation to synaptic plasticity, highlighting its role in modulating LTP and LTD.

Findings

Fluctuation in background activity attenuates LTD tendency.

Increased fluctuation enhances synaptic weight.

Fluctuation influences synaptic plasticity mechanisms.

Abstract

Synaptic plasticity is vital for learning and memory in the brain. It consists of long-term potentiation (LTP) and long-term depression (LTD). Spike frequency is one of the major components of synaptic plasticity in the brain, a noisy environment. Recently, we mathematically analysed the frequency-dependent synaptic plasticity (FDP) in vivo and found that LTP is more likely to occur with an increase in the frequency of background synaptic activity. Previous studies suggest fluctuation in the amplitude of background synaptic activity. However, little is understood about the relationship between synaptic plasticity and the fluctuation in the background synaptic activity. To address this issue, we performed numerical simulations of a calcium-based synapse model. Then, we found attenuation of the tendency to become LTD due to an increase in the fluctuation of background synaptic activity, leading to an enhancement of synaptic weight. Our result suggests that the fluctuation affect synaptic plasticity in the brain.