Topical review Learning and memory in pain pathways

The neurons of the central nervous system not only have the capacity to transmit, inhibit and weigh information, but they may also store information for prolonged periods of time (e.g. by use-dependent change in synaptic strength). Synaptic plasticity in hippocampus is an extensively studied cellular model of learning and memory and recent studies suggest that similar mechanisms also apply to pain pathways and may account for some forms of hyperalgesia, allodynia and analgesia. The discovery of synaptic longterm plasticity in nociceptive systems provides a relatively simple and straight forward concept for a number of clinically relevant phenomena. Here, I will brie ̄y summarize key aspects of synaptic plasticity in general. Then I will describe related changes at nociceptive synapses and discuss the potential relevance of these mechanisms for the development, the prevention and the treatment of chronic pain.