The Attentional Boost Effect (ABE) refers to the counterintuitive finding that words encoded with to-be-responded targets in a divided-attention condition are remembered better than words encoded with distractors. Previous studies suggested that the ABE-related enhancement of verbal memory depends upon the activation of abstract lexical representations. In the present study, we extend this hypothesis by embedding it in the context of a broader perspective, which proposes that divided attention in the ABE paradigm affects item-specific, but not relational, processing. To this purpose, we examined the ABE in the matched tasks of category-cued recall (CCRT: explicit memory) and category exemplar generation (CEGT: implicit memory). In addition, study time was varied (500, 1500 or 4000 ms), to further determine whether the attentional boost manipulation could influence late-phase elaborative processing. In agreement with the predictions of the item-specific account, the results showed that exemplars encoded with targets were recalled better than exemplars encoded with distractors in the CCRT, but not in the CEGT. Moreover, performance in the CCRT increased with study time, whereas the size of the ABE-related enhancement tended to decrease, further confirming that this effect hinges upon early phase encoding processes.

Changes in the residual memory variance are considered as a dynamic aspect of cognitive reserve (d-CR). We aimed to investigate for the first time the neural substrate associated with changes in the residual memory variance overtime in patients with amnestic mild cognitive impairment (aMCI). Thirty-four aMCI patients followed-up for 36 months and 48 healthy elderly individuals (HE) were recruited. All participants underwent 3T MRI, collecting T1-weighted images for voxel-based morphometry (VBM). They underwent an extensive neuropsychological battery, including six episodic memory tests. In patients and controls, factor analyses were used on the episodic memory scores to obtain a composite memory score (C-MS). Partial Least Square analyses were used to decompose the variance of C-MS in latent variables (LT scores), accounting for demographic variables and for the general cognitive efficiency level; linear regressions were applied on LT scores, striping off any contribution of general cognitive abilities, to obtain the residual value of memory variance, considered as an index of d-CR. LT scores and d-CR were used in discriminant analysis, in patients only. Finally, LT scores and d-CR were used as variable of interest in VBM analysis. The d-CR score was not able to correctly classify patients. In both aMCI patients and HE, LT1st and d-CR scores showed correlations with grey matter volumes in common and in specific brain areas. Using CR measures limited to assess memory function is likely less sensitive to detect the cognitive decline and predict the evolution of Alzheimer's disease. In conclusion, d-CR needs a measure of general cognition to identify conversion to Alzheimer's disease efficiently.

In the Attentional Boost Effect (ABE), images or words presented with to-be-responded target squares are later recognized more accurately than images or words presented with to-be-ignored distractor squares. Surprisingly, previous studies investigating the ABE have always examined young participants: thus, the question of whether this memory facilitation can be also observed in older adults has never been tested. The present study sought to fill this gap by examining whether healthy aging modulated the size of the ABE in 4 experiments in which the nature of the background stimuli (images vs. words), the length of the encoding trials (500 vs. 1,000 ms), and the type of instructions given to participants (incidental vs. intentional) were varied. In all cases, the results showed that the ABE was robust and significant in younger adults, whereas it was completely abolished in older adults. It is suggested that the detection of target squares required more attention resources in older than in younger adults, and that these resources were subtracted from the encoding of target-associated stimuli; thus, reducing or eliminating the ABE in the older group. Alternative explanations are also discussed. (PsycINFO Database Record

The Frontal Aslant Tract (FAT) has been described as a bundle connecting the Broca's area to the Supplementary Motor Area (SMA) and the pre-SMA in both hemispheres.The functional properties of this tract, and its role in degenerative dementia, such as Alzheimer's disease (AD) still need to be fully clarified. The aim of this study was to explore the microstructural integrity of the FAT in patients with AD and its potential relationship with cognitive functioning. Twenty-three patients with AD and 25 healthy subjects (HS) were enrolled. All subjects underwent cognitive and MRI examination.MRI including diffusion sequences was used for probabilistic tractography analysis. We