Synaptic plasticity rules with physiological calcium levels
Yanis Inglebert, Johnatan Aljadeff, Nicolas Brunel, Dominique Debanne
Abstract
Significance Spike-timing–dependent plasticity (STDP) is a form of synaptic modification thought to be a primary mechanism underlying formation of new memories. Despite triggering tremendous interest since its discovery, it is still unclear whether plasticity rules inferred from in vitro experiments are correct in physiological conditions. While STDP induction depends on intracellular calcium influx, all previous studies used an abnormally high concentration of extracellular calcium. Here, we study the influence of extracellular calcium on synaptic plasticity. We show that pairing single pre- and postsynaptic action potentials at hippocampal synapses does not induce plasticity in the physiological range of extracellular calcium. Rather, synaptic plasticity is induced only when bursts of postsynaptic spikes are used or when neurons fire at sufficiently high frequency.