Electrophysiological correlates of the retrieval of emotional and non-emotional context.

In two experiments, words were presented in negatively or neutrally valenced sentences. At test, subjects made old/new recognition judgments to these words. In Experiment 2 only, for words judged old, subjects also indicated whether the words had been studied in a neutral or a negative context. In Experiment 1, left parietal old/new event-related brain potential (ERP) effects were larger and more sustained when elicited by words that had been studied in negative sentences, and a right frontal old/new effect was elicited by these words exclusively. In Experiment 2, the left parietal and right frontal effects elicited by old words correctly assigned to their study context were equivalent in size regardless of the nature of the context; a third ERP old/new effect, maximal over posterior scalp regions, was seen only for words from negative contexts. The findings indicate that incidental retrieval of emotional context gives rise to greater activation in neural systems supporting conscious recollection than does retrieval of nonemotional context. When contextual retrieval is intentional, recollection of emotional and non-emotional information are associated with equivalent engagement of these systems. The findings from Experiment 2 suggest that additional neural circuitry may be activated selectively by emotionally valenced episodic information.