Evaluating underlying neuronal activity associated with escape/avoidance behavior in response to noxious stimulation in adult rats

The place escape/avoidance paradigm (PEAP) is a behavioral test designed to quantify the level of unpleasantness evoked by painful stimuli by assessing the willingness of a subject to escape/avoid a preferred area when it is associated with noxious stimulation. Previous studies have demonstrated that escape/avoidance behavior is dependent on activity in the anterior cingulate cortex (ACC), a region of the limbic system involved in processing the emotional component of pain in humans and animals. Analysis of c-Fos expression in the ACC confirmed that the escape/avoidance response to noxious stimuli corresponds to changes in neural activation in this region. Behavioral tests such as the PEAP may be more sensitive to changes in supraspinal pain processing and could contribute to the development of novel analgesics in the future.

► Carrageenan injection produced mechanical hypersensitivity and escape/avoidance of stimulation to the injected paw.
► Escape/avoidance of noxious stimulation was related to the level of neuronal activation in the anterior cingulate cortex.
► The current results provide additional support for the role of the ACC in processing pain affect.
► The results further validate the place escape/avoidance paradigm as a tool for assessing the emotional component of pain.