Direct and generative retrieval of autobiographical memories : the roles of visual imagery and executive processes

Two experiments used a dual task methodology to investigate the role of visual imagery and executive resources in the retrieval of specific autobiographical memories. In Experiment 1, dynamic visual noise led to a reduction in the number of specific memories retrieved in response to both high and low imageability cues, but did not affect retrieval times. In Experiment 2, irrelevant pictures reduced the number of specific memories but only in response to low imageability cues. Irrelevant pictures also increased response times to both high and low imageability cues. The findings are in line with previous work suggesting that disrupting executive resources may impair generative, but not direct, retrieval of autobiographical memories. In contrast, visual distractor tasks appear to impair access to specific autobiographical memories via both the direct and generative retrieval routes, thereby highlighting the potential role of visual imagery in both pathways

Survival processing versus self-reference : a memory advantage following descriptive self-referential encoding

Previous research has shown that rating words for their relevance to a survival scenario leads to better retention of the words than rating them for self-reference. Past studies have, however, relied exclusively on an autobiographical self-reference task in which participants rate how easily a common noun brings to mind a personal experience. We report five experiments comparing survival processing to a descriptive self-reference task in which participants rated how well trait words described them. Rating trait adjectives for survival value led to higher levels of recall and recognition than rating them for their relevance to a moving home scenario. Rating the adjectives for self-reference, however, led to higher levels of recall (Experiments 1 and 3) and recollection (Experiment 2) than survival rating. Experiment 4 replaced trait adjectives with trait nouns and found that self-reference led to greater recognition accuracy than survival processing. Experiment 5 used trait nouns followed by tests of free recall and found a memory advantage following self-reference that was not influenced by the imageability of the stimuli. The findings are discussed in terms of theories of the survival processing and self-reference effects and the relationship between them

Effects of expectancy and agency on the feedback-related negativity

There is an evolving body of research using Event-Related Potentials (ERPs) to study electrophysiological activity in the brain associated with feedback processing in gambling tasks. In particular, investigators have examined the roles of outcome valence (Gehring & Willoughby, 2002) and outcome probability (Bellebaum & Daum, 2008) on an ERP component known as the Feedback-Related Negativity (FRN), whose amplitude has been shown to distinguish positive and negative outcomes. The current study examined the possibility that FRN amplitude might also be modulated by a person\u27s subjective expectation of a particular outcome (expectancy), as well as whether or not an outcome was the result of their own actions or those of another (agency). Consistent with past research, the results of Experiment 1 of this study show an increase in the amplitude of the FRN when participants are given feedback indicating a loss during a decision-making task. This increased negativity in response to negative feedback was greater for trials in which participants were led to expect a win, though only for trials in which the value of the outcome was relatively smaller. In Experiment 2, the FRN was also found to be greater in amplitude on trials where losses resulted from choices made by participants as opposed to the choices of a computerized opponent. The findings of the current study suggest a somewhat nuanced account of the FRN in which amplitude is sensitive to individual expectations about winning and losing as well as the individual\u27s perceived role in wins and losses

Adaptive false memory: Imagining future scenarios increases false memories in the DRM paradigm

Previous research has shown that rating words for their relevance to a future scenario enhances memory for those words. The current study investigated the effect of future thinking on false memory using the Deese/Roediger–McDermott (DRM) procedure. In Experiment 1, participants rated words from 6 DRM lists for relevance to a past or future event (with or without planning) or in terms of pleasantness. In a surprise recall test, levels of correct recall did not vary between the rating tasks, but the future rating conditions led to significantly higher levels of false recall than the past and pleasantness conditions did. Experiment 2 found that future rating led to higher levels of false recognition than did past and pleasantness ratings but did not affect correct recognition. The effect in false recognition was, however, eliminated when DRM items were presented in random order. Participants in Experiment 3 were presented with both DRM lists and lists of unrelated words. Future rating increased levels of false recognition for DRM lures but did not affect correct recognition for DRM or unrelated lists. The findings are discussed in terms of the view that false memories can be associated with adaptive memory functions

Molecular biology on a microfluidic chip

We have developed microfluidic chips for automating molecular biology processes such as gene ligation and gene transformation from nanolitre sample volumes with parallel architecture. Unlike conventional tube methods with cumbersome pipetting procedures, all processes, including metering of samples, ligation and transformation, were carried out in the microfluidic chips through pneumatic control of the nanofluid. The microfluidic devices presented here offer an illustration of some of the basic physics that arises when trying to miniaturize and automate biological techniques

Permutation Inference for Canonical Correlation Analysis

Canonical correlation analysis (CCA) has become a key tool for population neuroimaging, allowing investigation of associations between many imaging and non-imaging measurements. As other variables are often a source of variability not of direct interest, previous work has used CCA on residuals from a model that removes these effects, then proceeded directly to permutation inference. We show that such a simple permutation test leads to inflated error rates. The reason is that residualisation introduces dependencies among the observations that violate the exchangeability assumption. Even in the absence of nuisance variables, however, a simple permutation test for CCA also leads to excess error rates for all canonical correlations other than the first. The reason is that a simple permutation scheme does not ignore the variability already explained by previous canonical variables. Here we propose solutions for both problems: in the case of nuisance variables, we show that transforming the residuals to a lower dimensional basis where exchangeability holds results in a valid permutation test; for more general cases, with or without nuisance variables, we propose estimating the canonical correlations in a stepwise manner, removing at each iteration the variance already explained, while dealing with different number of variables in both sides. We also discuss how to address the multiplicity of tests, proposing an admissible test that is not conservative, and provide a complete algorithm for permutation inference for CCA.Comment: 49 pages, 2 figures, 10 tables, 3 algorithms, 119 reference

Certain Adenylated Non-Coding RNAs, Including 5′ Leader Sequences of Primary MicroRNA Transcripts, Accumulate in Mouse Cells following Depletion of the RNA Helicase MTR4

RNA surveillance plays an important role in posttranscriptional regulation. Seminal work in this field has largely focused on yeast as a model system, whereas exploration of RNA surveillance in mammals is only recently begun. The increased transcriptional complexity of mammalian systems provides a wider array of targets for RNA surveillance, and, while many questions remain unanswered, emerging data suggest the nuclear RNA surveillance machinery exhibits increased complexity as well. We have used a small interfering RNA in mouse N2A cells to target the homolog of a yeast protein that functions in RNA surveillance (Mtr4p). We used high-throughput sequencing of polyadenylated RNAs (PA-seq) to quantify the effects of the mMtr4 knockdown (KD) on RNA surveillance. We demonstrate that overall abundance of polyadenylated protein coding mRNAs is not affected, but several targets of RNA surveillance predicted from work in yeast accumulate as adenylated RNAs in the mMtr4KD. microRNAs are an added layer of transcriptional complexity not found in yeast. After Drosha cleavage separates the pre-miRNA from the microRNA\u27s primary transcript, the byproducts of that transcript are generally thought to be degraded. We have identified the 5′ leading segments of pri-miRNAs as novel targets of mMtr4 dependent RNA surveillance