Behavioral reconsolidation interference with episodic memory within-subjects is elusive.

In studies of behavioral reconsolidation interference, reactivation of a consolidated memory using some form of reminder is followed by the presentation of new information that can cause interference with that memory. Under these conditions, the interference not only impairs retrieval by indirect processes such as cue interference, but supposedly disrupts the original memory trace directly. Almost all studies of behavioral reconsolidation interference in episodic memory in humans have employed between-subjects paradigms, and deduced reminder effects from intrusion errors. Such studies might introduce confounds arising, for example, from differences in retrieval strategies engendered by the pre-test treatments. We therefore set out to examine whether behavioral reconsolidation interference in episodic memory might be demonstrated within-subjects and by direct memory strength rather than intrusion errors. In three separate experiments, we attempted to disrupt reconsolidation of episodic object-picture memory using a reminder + retroactive interference manipulation. We applied the manipulation over three consecutive days, using a forced-choice recognition test without intrusions from interfering learning, keeping all other study and test parameters constant. No effects of reminder-potentiated interference were observed for measures of accuracy, response times, subjective expressions of recollection, or levels of confidence, as substantiated by Bayesian analyses. These results highlight the difficulty of observing clear behavioral reconsolidation interference effects within-subjects in human episodic memory, and provide some indications of what might be boundary conditions for its demonstration.

Parietal lesion effects on cued recall following pair associate learning.

We investigated the involvement of the posterior parietal cortex in episodic memory in a lesion-effects study of cued recall following pair-associate learning. Groups of patients who had experienced first-incident stroke, generally in middle cerebral artery territory, and exhibited damage that included lateral posterior parietal regions, were tested within an early post-stroke time window. In three experiments, patients and matched healthy comparison groups executed repeated study and cued recall test blocks of pairs of words (Experiment 1), pairs of object pictures (Experiment 2), or pairs of object pictures and environmental sounds (Experiment 3). Patients' brain CT scans were subjected to quantitative analysis of lesion volumes. Behavioral and lesion data were used to compute correlations between area lesion extent and memory deficits, and to conduct voxel-based lesion-symptom mapping. These analyses implicated lateral ventral parietal cortex, especially the angular gyrus, in cued recall deficits, most pronouncedly in the cross-modal picture-sound pairs task, though significant parietal lesion effects were also found in the unimodal word pairs and picture pairs tasks. In contrast to an earlier study in which comparable parietal lesions did not cause deficits in item recognition, these results indicate that lateral posterior parietal areas make a substantive contribution to demanding forms of recollective retrieval as represented by cued recall, especially for complex associative representations.

Associative recognition processes are modulated by modality relations.

Although memory of episodic associations is generally considered to be recollective in nature, it has been suggested that when stimuli are experienced as a unit, familiarity-related processes might contribute to their subsequent associative recognition. Furthermore, intradomain associations are believed to be unitized more readily than interdomain associations. To assess these claims, we tested associative recognition following two types of pair associate learning. In the unimodal task, stimulus pairs were pictures of common objects, whereas in the cross-modal task, stimulus pairs consisted of an object picture and an unrelated environmental sound. At test, participants discriminated intact from recombined pairs while ERPs were recorded. In the unimodal task only, associative recognition was accompanied by a robust frontal deflection reminiscent of a component commonly interpreted as related to familiarity processes. In contrast, ERP correlates of associative recognition observed at more posterior sites, akin to a component that has been related to recollection, were apparent in both tasks. These findings indicate that retrieval of unimodal associations can be supported by familiarity-related processes that are dissociable from recollective processes required for the retrieval of cross-modal associations.

Parafoveal perception during sentence reading? An ERP paradigm using rapid serial visual presentation (RSVP) with flankers.

We describe a new procedure using event-related brain potentials to investigate parafoveal word processing during sentence reading. Sentences were presented word by word at fixation, flanked 2° bilaterally by letter strings. Flanker strings were pseudowords, except for the third word in each sentence, which was flanked by either two pseudowords or a pseudoword and a word, one on each side. Flanker words were either semantically congruent or incongruent with the sentence context. P2 (175-375 ms) amplitudes were less positive for contextually incongruent than congruent flanker words but only with flanker words in the right visual field for English and in the left visual field in Hebrew. Flankered word presentation thus may be a suitable method for the electrophysiological study of parafoveal perception during sentence reading.