Some patients with amnesia are able to retain new information for much longer than expected when the time that follows new learning is devoid of further stimuli. Animal work shows that the absence or delaying of interference improves long-term memory consolidation. Our study suggests that this is also true for at least some patients with amnesia. Retention of new verbal material was significantly higher in a sample of patients with amnesia (N = 12) when interference occurred at the end of a 9-min delay interval than when it occurred in the middle or at the beginning of the interval. Such findings cannot be accounted for by the mere use of explicit short-term memory rehearsal. Any such rehearsal should have been blocked by the interference, irrespective of interference onset, thus leading to poor retention in all three conditions. The current findings suggest that at least some of the severe forgetting observed in amnesia is the product of a disruption of memory consolidation by immediate postlearning interference.

Abstract:The neuroanatomical bases of bilingualism have recently received intensive attention.However, it is still a matter of debate how the brain structure changes due to bilingual experience since current findings are highly variable. The aim of this review is to examine these structural studies from a methodological perspective and to discuss two major methodological problems that could give rise to this variability. The first problem is sample selection, an issue directly related to the heterogeneous nature of bilingualism. The second problem is the inconsistency in the methods used for the analysis of brain imaging data. This review reveals that although structural changes related to bilingualism have been reported in regions comprising language/cognitive control and language processing, these results are not yet sufficiently numerous or consistent to allow important generalizations to be reached. Consequently, current evidence offers ambiguous support for neural models of bilingualism. This shortcoming in the field is exacerbated by critical methodological differences between studies that only further complicate the matter. We conclude by identifying issues that should be taken into consideration so that studies are more comparable and results are easier to aggregate and interpret. We also point out future directions that would allow for progress in the field.

a b s t r a c tBilingualism has been argued to benefit executive functioning. However, recent research suggests that this advantage may stem from uncontrolled factors or incorrectly matched samples. In this study we test the effects of bilingualism on elderly lifelong bilinguals whose cognitive abilities are in decline, thus making any benefits more salient. Firstly we compare 24 bilinguals and 24 carefully matched monolinguals on verbal and the numerical Stroop tasks, obtaining no differences in monitoring or inhibitory measures. Secondly we explore the modulations that the proficiency in the L2 might cause to executive control functions, as measured by the same tasks, by testing 70 elderly bilinguals who vary in their L2 mastery from very low to perfectly fluent. Results show no modulation in any of the indices due to L2 proficiency. These results add to the growing body of evidence showing that the bilingual advantages might indeed be due to other factors rather than bilingualism.

Available online 15 September 2016The bilingual advantage has been subject of research repeatedly over the last decade. Many studies have supported the idea of the existence of a higher functioning in domain general cognitive abilities among bilingual samples as compared to monolingual samples. However, this idea has been recently challenged by a number of scholars, and a recent body of evidence suggests that the acquisition of a new language does not necessarily involve an enhancement of domain-general non-linguistic abilities. In the current study we aimed at exploring the relationship between language learning and switching ability in elderly monolingual participants who learned a second language during a whole academic year. A colour-shape switching task was used as a measure of switching ability and was administered twice in a pre-test/post-test design, both to the critical group of seniors attending a language-learning course on a regular basis and to a group of age-matched monolingual seniors who did not attend to any language-learning course and that served as controls. Results showed that switching costs in the post-test were not significantly different from those in the pre-test in either the experimental or the control groups, demonstrating that the acquisition of a second language in the elderly does not necessarily lead to an enhancement of switching ability as measured by switching costs. We acknowledge the need of further longitudinal L2 training studies to reach clear conclusions on the effects of language learning in domain-general executive control.This research has been partially funded by grants PSI2015-65689-P and SEV-2015-0490 from the Spanish Government, PI2015-1-27 from the Basque Government, ERC-AdG-295362 grant from the European Research Council, the AThEME project funded by the European Union (grant number 613465), and by a research grant from the BBVA Foundation

Although subtle anatomical anomalies long precede the onset of clinical symptoms in Alzheimer's disease, their impact on the reorganization of brain networks underlying cognitive functions has not been fully explored. A unique window into this reorganization is provided by presymptomatic cases of familial Alzheimer's disease (FAD). Here we studied neural circuitry related to semantic processing in presymptomatic FAD cases by estimating the intracranial sources of the N400 event-related potential (ERP). ERPs were obtained during a semantic-matching task from 24 presymptomatic carriers and 25 symptomatic carriers of the E280A presenilin-1 (PS-1) mutation, as well as 27 noncarriers (from the same families). As expected, the symptomatic-carrier group performed worse in the matching task and had lower N400 amplitudes than both asymptomatic groups, which did not differ from each other on these variables. However, N400 topography differed in mutation carrier groups with respect to the noncarriers. Intracranial source analysis evinced that the presymptomatic-carriers presented a decrease of N400 generator strength in right inferior-temporal and medial cingulate areas and increased generator strength in the left hippocampus and parahippocampus compared to the controls. This represents alterations in neural function without translation into behavioral impairments. Compared to controls, the symptomatic-carriers presented a similar anatomical shift in the distribution of N400 generators to that found in presymptomatic-carriers, albeit with a larger reduction in generator strength. The redistribution of N400 generators in presymptomatic-carriers indicates that early focal degeneration associated with the mutation induces neural reorganization, possibly contributing to a functional compensation that enables normal performance in the semantic task.