Amygdala in the control of neuropathic pain

Amygdala has a key role in the processing of primary emotions such as fear. Additionally, a subdivision of the central nucleus of the amygdala is particularly involved in processing of nociceptive signals. The amygdala may also contribute to regulation of pain through its reciprocal connections with other brain areas. Here we briefly review recent findings on neural plasticity of the amygdala in peripheral neuropathy. Peripheral nerve injury may induce neurogenesis in the amygdala of adult animals and this is accompanied by changes in synaptic functions and response characteristics of amygdaloid neurons. Moreover, the pain-regulatory action of amygdaloid neurotransmitters and neurotransmitter receptors (such as glutamate acting on the metabotropic glutamate receptor 1 or corticotropin-releasing factor (CRF) acting on the CRF1 receptor) may change following peripheral nerve injury. It is proposed that these plastic changes of the amygdala following peripheral nerve injury contribute to the sensory and affective aspects of pain in neuropathy and to the comorbidity of neuropathic pain and mood disorders.