Table 1 |.

Classification of commonly used behavioural measures of pain

Category	Evoked or non-evoked?	Example behaviours	Pros	Cons
Elective	Non-evoked	Cage hanging, nest building and social interaction	Similar to human pain manifestations Can be tested in home cage	May not be specific to pain
Nocifensive	Non-evoked	Grimace, writhing, gait changes and ultrasonic vocalizations	Automated scoring possible	Infrequently observed in chronic models Stress associated with testing apparatus
Survival	Non evoked	Feeding and grooming	Easy to perform Can be tested in home cage	May not be specific to pain
Conditioned	Non-evoked and evoked	CPP, CPA and operant measures	Measures affective/motivational aspect of pain	Requires specialized equipment Time intensive Stress associated with testing apparatus
Reflexive	Evoked	von Frey, radiant heat withdrawal and the acetone test	Easy to perform Can control stimulus intensity	Not reflective of affective state Experimenter presence, skill and bias affect results May reflect motor deficits, not analgesia Stress associated with testing apparatus

CPA, conditioned place aversion; CPP, conditioned place preference.