Synaptic plasticity and pain aversion.

Negative affective emotions are defined as the conceptual feature of pain. A number of clinical and animal studies have indicated that the limbic system including the anterior cingulate cortex (ACC) and amygdala plays a critical role in the processing of affective components of pain. Glutamatergic transmission plays an important role in the processing of affective aspects of pain. Long-term changes on glutamatergic synapses contribute to the expression of aversion behavior induced by pain. In this article, the neurocircuits involved in the processing of affective aspects of pain, the glutamatergic synaptic plasticity in these brain regions, and the epigenetic mechanisms underlying pain-related synaptic plasticity will be reviewed and discussed. New discoveries regarding the interaction between the synaptic plasticity and affective components of pain may advance our understanding on the pain mechanism, and lead to new strategies for pain treatment.