The association between inhibition and pain tolerance in the elderly: evidence from event-related potentials.

BACKGROUND Age-related alterations in both pain perception and inhibitory functions have been observed, but the relationship between the two in older adults remains unclear. Previous studies were mainly based on behavioural measures which do not allow assessment of underlying neural mechanisms. METHODS The present study evaluated the association between inhibition and pain perception in 26 healthy elderly volunteers. Cognitive inhibition was assessed by Stroop interference tests and response inhibition by a Go/No-go task. Event-related potentials during the Go/No-go task were recorded to provide brain activity data. Pain perception was assessed with the cold pressor test, in which subjects were asked to resist pain as long as possible. The exposure time (ET), intensity of tolerated pain and unpleasantness were interpreted as psychophysiological outcomes of pain. RESULTS We observed that better performance on cognitive inhibition, assessed by Stroop interference tasks, was correlated with higher intensity of tolerated pain. Greater brain activity during response inhibition, evaluated as larger amplitude (P3), and shorter latency (N2) to a No-go stimuli were correlated with longer ET-pain tolerance. CONCLUSIONS In the healthy elderly, the neuronal circuits of cognitive inhibition and conscious pain control may overlap, and brain regions engaged in response inhibition may be more involved in behavioural response of pain.