Does past/current pain change pain experience? Comparing self-reports and pupillary responses

Area of Science:

• Neuroscience
• Pain Research
• Psychology

Background:

• Pain perception is widely recognized as subjective, often limited to self-reports.
• The interaction between past and present pain experiences on physiological pain responses remains under-investigated.

Purpose of the Study:

• To investigate how prior pain exposure influences subjective pain reporting and objective pupillary responses to acute pain.
• To explore the modulatory effects of pain history on pain perception.

Main Methods:

• Forty-seven participants underwent two cold pressor tasks (CPTs), with group order of pain intensity (4°C-10°C vs. 10°C-4°C) varied.
• Participants reported pain intensity during CPTs, and pupillary responses were measured.
• Pain reappraisal was performed after the first CPT session.

Main Results:

• Both groups showed significant differences in self-reported pain ratings between CPT sessions, with a larger discrepancy in the 10°C-4°C group.
• Pupillary responses to pain differed significantly in the 4°C-10°C group and marginally in the 10°C-4°C group.
• Pain reappraisal did not significantly alter self-reported pain in either group.

Conclusions:

• Past pain experiences demonstrably alter both subjective and physiological pain responses.
• This suggests that pain memory plays a crucial role in modulating current pain perception and its objective correlates.