Pain Anticipation and Memory: An Event-Related Potential Study
MetadataShow full metadata
It is known that physical stress enhances episodic memory, but less is known about effects of psychological stressors such as pain anticipation on episodic memory and associated neural activity. The current study examined the effect of pain anticipation on episodic memory using event-related potentials (ERPs). Eighteen participants encoded 240 emotional words. Half of the words appeared in a font color that signaled threat of electric shock (threat words), although shock was only delivered on six randomly- determined threat trials. Recognition memory for the words was tested shortly after encoding. It was hypothesized that stress induced by pain anticipation would improve memory for threat over safe (no threat of shock) words, recognition ERPs would show typical old/new effects in the 500-700 ms time window, and that these old/new effects would be larger for threat than for safe words. However, results indicated better memory for safe than for threat words, and ERP amplitudes were more negative for old compared with new words in the 500-700 ms time window; typical old/new effects show the reverse pattern (more positive amplitudes for old compared with new stimuli). The observed ERP effect was also larger for safe than for threat words. Whereas previous research shows memory benefits due to stress at encoding, here, memory impairment was observed. Explanations for results could include lingering acute stress at retrieval, shallow encoding of threat words, or the devotion of resources to stress suppression during threat-word encoding. These results suggest that acute stress at encoding can impair memory in some circumstances.