A new perspective on the anterior cingulate cortex and affective pain.

Pain is a complex experience including sensory-discriminative and emotional-affective components. Base on the intensity and chronification of pain, pain is divided into physiological and pathological pain. Anterior cingulate cortex (ACC), which is activated by noxious and contextual stimuli, is involved in pain processing, especially affective pain, the neural mechanisms of the ACC involvement in affective pain have yet to be elaborated. This review summarizes the main progresses and recent findings from our and other laboratories regarding the ACC and affective pain. Most evidence provided new insights into the neural mechanisms underlying affective pain. Excitation of ACC pyramidal neurons is necessary and sufficient for the pain-related negative emotion. We also sketched other brain regions associated with the ACC and discussed the role of these brain regions in affective pain. Actually, it is likely that the neural network between these brain regions is critical for the negative affect of pain. In particular, the important advances within the optogenetic filed provide new opportunities to deepen and expand our understanding of the affective pain.