Associating synaptic and intrinsic plasticity

Intrinsic plasticity is the persistent modification of a neuron’s intrinsic electrical properties by neuronal or synaptic activity. It is mediated by changes in the expression level or biophysical properties of ion channels in the membrane, and can affect such diverse processes as synaptic integration, subthreshold signal propagation, spike generation, spike backpropagation, and meta-plasticity. The function of intrinsic plasticity in behaving animals is uncertain but there is experimental evidence for several distinct roles: as part of the memory engram itself, as a regulator of synaptic plasticity underlying learning and memory, and as a component of homeostatic regulation.

It is important to note that intrinsic plasticity is distinct from synaptic plasticity, which involves changes at the synapse between two neurons rather than changes in the electrical properties within a single neuron. It is also important to note that there are closely-related phenomena that can affect a neuron's excitability – such as neuromodulation, structural plasticity, short-term plasticity due to channel kinetics, and neurodevelopment – but which are generally excluded from the term intrinsic plasticity.