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Offset analgesia: a temporal contrast mechanism for nociceptive information
Marc D Yelle1, June M Rogers, Robert C Coghill
1Wake Forest School of Medicine, Department of Neurobiology and Anatomy, Medical Center Blvd, Winston-Salem, NC 27157, USA.
Pain
|May 30, 2007
Summary
Temporal filtering of sensory information is key. This study reveals offset analgesia, a pain reduction phenomenon, suggests central nervous system temporal filtering of nociceptive signals, enhancing contrast detection.
Area of Science:
- Neuroscience
- Pain Perception
- Sensory Processing
Background:
- Temporal filtering is crucial for processing sensory information but has not been identified for nociception (pain signals).
- Offset analgesia, a significant pain reduction upon slight noxious stimulus decrease, implies a temporal filtering mechanism for pain.
Purpose of the Study:
- To investigate the hypothesis that a temporal filtering mechanism is active during the offset of noxious stimuli.
- To explore the role of central mechanisms in offset analgesia and its spatial interactions.
Main Methods:
- Subjects rated heat pain intensity while stimulus fall rates were manipulated (-0.5 to -5.0 °C/s).
- Paired noxious stimuli were presented to assess if offset analgesia from one stimulus could inhibit pain from another.
Main Results:
- Psychophysical fall rates of pain perception were faster than stimulus fall rates, indicating temporal filtering.
- Subjects reported no pain at stimulus temperatures still considered noxious (47.2 °C) due to this filtering.
- Offset analgesia induced proximally, but not distally, to a second noxious stimulus showed asymmetric spatial inhibition.
Conclusions:
- Offset analgesia is partly mediated by central nervous system mechanisms.
- These findings demonstrate a temporal filtering of sensory information that sharpens the perception of dynamic decreases in noxious stimulus intensity.
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