Content dependence of the electrophysiological correlates of recollection

Abstract

The neural correlates of episodic retrieval ('recollection') have been shown to differ according to the content of retrieved episodes. It has been hypothesized that these content-dependent differences reflect the 'reinstatement' of encoding-related processes or representations at the time of recollection. It remains unclear, however, whether these effects directly reflect the recollection of differential episodic content, as would be predicted by the reinstatement hypothesis, or whether they are instead associated with processes that are contingent on successful recollection. To address this issue, the present study employed event-related potentials (ERPs), permitting the investigation of the temporal dynamics of content-dependent neural effects during retrieval, and in particular, their onset with respect to well-established ERP correlates of recollection, such as the left parietal old-new effect. Subjects studied a series of words that were each presented in the context of one of two encoding tasks. One task required the covert generation of a sentence incorporating each word, whereas the other required imagining the object corresponding to each word within a superimposed scenic picture. Memory for the words was subsequently tested with the 'remember/know' procedure. ERPs elicited by recollected words differed according to the prior encoding history of the word, beginning at approximately 300 ms following word onset. These content-dependent ERP differences were maximal over the anterior scalp and, importantly, onset as early as the left parietal old-new effect. The findings demonstrate that content-dependent neural activity during retrieval can occur in a timeframe that is compatible with a direct role in the recollection and representation of episodic information.

Electrophysiological correlates of remembering emotional pictures

“…These observations are consistent with the notion of a posterior LPC observed in previous studies (Rugg and Curran, 2007). The fact that fronto-central old-new differences appear to co-exist with this effect has been frequently observed in previous old-new studies (Wilding, 2000;Curran et al, 2006;Curran and Hancock, 2007;Johnson et al, 2008;Weymar et al, 2009), including studies reporting RememberNew scalp distributions (Voss and Paller, 2009a). This effect probably reflects a late persistence of the early frontal effect (Curran and Hancock, 2007).…”

Tracking lexical consolidation with ERPs: Lexical and semantic-priming effects on N400 and LPC responses to newly-learned words

“…Second, topographical differences in the LPC window have been linked to episodic memory retrieval (Johnson et al, 2008;Peters and Daum, 2009;Yick and Wilding, 2008). For instance, Peters and Daum (2009) studied LPC responses during retrieval of (known) words that had been paired with either a sound, a picture of a scene, or a picture of a face.…”

Episodic retrieval involves early and sustained effects of reactivating information from encoding

“…As described in the Introduction, the existing fMRI evidence regarding this issue can be interpreted in at least two ways (for related discussions, see Johnson and Rugg, 2007;Johnson et al, 2008). One interpretation is that the reactivation of neural patterns occurs shortly after the presentation of a memory cue, as would be expected if it is closely tied to the conscious retrieval of episodic information (i.e.…”