Chapter 14 - Synaptic Plasticity

Abstract

Historically, after neurons and their fine dendrites and axons were visualized using the Golgi stain, it was debated whether the structure of the neuron was fixed or could change. In the late 1800s and early 1900s, Ramon y Cajal proposed that the site of contact between individual neurons might change in response to experience. Cajal was correct, but these changes are not restricted to structural alterations; they also include functional changes in activity of these contacts. In the preceding chapters we have covered the details of how nerve terminals convert action potential activity into chemical neurotransmitter release that can be sensed by neighboring cells. Furthermore, we detailed how these neurotransmitter release events are sensed by postsynaptic partners (often at their dendritic spines) and how these postsynaptic neurons integrate this input to generate a decision to fire an action potential and communicate to the next neuron in the circuit. Importantly, neither synaptic communication between neurons, nor the structures (axons and dendrites) that mediate this communication are fixed; they can be modified based on different patterns of neuronal activity, the coincident action of multiple neurotransmitter receptors, and biochemical signals within cells. The ability of neurons to modify their synaptic communication is called synaptic plasticity.