Taxonomy of pain behaviors and associated examples

Type of BehaviorNotationPreclinical ExamplesClinical Correlates
Unconditioned behavior: US→URPS→URStimulation of withdrawal responses,  writhing, flinching, grimacingSame
PS→[US→UR]Depression of locomotion, feeding, wheel  running, burrowing, nestingImpaired physical functioning
Classically conditioned behavior: CS+US; CS→CRPS+CS; CS→CRConditioned place avoidance; fear  conditioningAvoidance, anxiety, fear
PS → [US+CS; CS→CR]Conditioned place preference to putative  analgesic treatmentsPlacebo analgesia
Operant behavior: SD→R→SCPS→R→SCDiscrimination of a noxious stimulusVerbal reports of pain intensity or  quality
SD→R→PSPunishment with a noxious stimulusMovement-induced pain
PS→[SD→R→SC]Depression of operant responding for food  or brain stimulationImpaired physical functioning