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Introduction: Recent views posit that precise control of the interceptive timing can be achieved by combining on-line processing of visual information with predictions based on prior experience. Indeed, for interception of free-falling objects under gravity's effects, experimental evidence shows that time-to-contact predictions can be derived from an internal gravity representation in the vestibular cortex. However, whether the internal gravity model is fully engaged at the target motion outset or reinforced by visual motion processing at later stages of motion is not yet clear. Moreover, there is no conclusive evidence about the relative contribution of internalized gravity and optical information in determining the time-to-contact estimates. Methods: We sought to gain insight on this issue by asking 32 participants to intercept free falling objects approaching directly from above in virtual reality. Object motion had durations comprised between 800 and 1100 ms and it could be either congruent with gravity (1 g accelerated motion) or not (constant velocity or -1 g decelerated motion). We analyzed accuracy and precision of the interceptive responses, and fitted them to Bayesian regression models, which included predictors related to the recruitment of a priori gravity information at different times during the target motion, as well as based on available optical information. Results: Consistent with the use of internalized gravity information, interception accuracy and precision were significantly higher with 1 g motion. Moreover, Bayesian regression indicated that interceptive responses were predicted very closely by assuming engagement of the gravity prior 450 ms after the motion onset, and that adding a predictor related to on-line processing of optical information improved only slightly the model predictive power. Discussion: Thus, engagement of a priori gravity information depended critically on the processing of the first 450 ms of visual motion information, exerting a predominant influence on the interceptive timing, compared to continuously available optical information. Finally, these results may support a parallel processing scheme for the control of interceptive timing. [ABSTRACT FROM AUTHOR]

Word clustering (i.e., the ability to reproduce the same word pairs in consecutive recall trials of an unrelated word list) has been extensively investigated as a proxy of subjective organization (SO) of memorandum. In healthy subjects and in groups of brain‐damaged patients, the rate of SO generally predicts accuracy of word list recall. This study aimed at evaluating SO in the performance of patients with Parkinson's disease (PD) on a word list recall task in order to investigate the basic mechanisms of episodic memory impairment that are frequently observed in these patients. For this purpose, 56 PD patients, who were stratified according to the presence and quality of mild cognitive impairment (MCI), and a group of healthy controls (HCs) were administered a word list task and an extensive battery of neuropsychological tests. Results showed that recall accuracy on the word list task progressively decreased passing from HC to PD patients without cognitive impairment, to patients with single‐domain dysexecutive MCI and to patients with multiple‐domain dysexecutive and amnesic MCI. Conversely, only the latter PD group showed a lower SO score than that achieved by the other groups. In the overall PD group, correlational and regression analyses demonstrated that SO scores and a composite score of executive functions were not reciprocally related, but both provided an independent and significant contribution to the prediction of word list recall accuracy. These data are discussed in terms of the contribution of executive functions and hippocampal storage processes to the onset of memory impairment in PD. [ABSTRACT FROM AUTHOR]

How prospective memory (PM) weakens with increasing age has been largely debated. We hypothesized that automatic and strategic PM processes, respectively mediated by focal and non-focal cues, are differently affected by aging, even starting from 50–60 years of age. We investigated this issue using a 2 × 2 design in which focal and non-focal experimental conditions were created by varying the conjoint nature of the ongoing task (lexical decision vs. syllable matching tasks) and the PM cue (words vs. syllables). In the whole-brain analysis we found that the left inferior frontal gyrus and the middle cingulate cortex were more activated when young compared to older individuals performed a PM task; moreover, the anterior cingulate cortex was selectively activated during non-focal PM when the cues were words. In a region-of-interest analysis we observed that the medial and the lateral portions of the rostral prefrontal cortex were associated with the focal and non-focal conditions respectively, more in young than in older adults. Our findings provide evidence in support of early age-related differences in automatic/strategic PM functioning. [ABSTRACT FROM AUTHOR]

Objective: The aim of this paper was to assess the efficacy of process-based cognitive training (pb-CT) combined with reminiscence therapy (RT) in patients with mild Alzheimer's disease (mAD) and mild cognitive impairment (MCI) and in healthy elderly (HE) subjects. Methods: This multicenter, randomized, controlled trial involved 348 participants with mAD, MCI, and HE from four European countries. Participants were randomly assigned to two arms of a crossover design: those in arm A underwent 3 months of computerized pb-CT for memory and executive functions combined with RT and 3 months of rest; those in arm B underwent the reverse. The primary outcome was the effect of the training on memory and executive functions performance. The secondary outcome was the effect of the training on functional abilities in mAD assessed with the instrumental activities of daily living. Results: We found a significant effect of the training for memory in all three groups on delayed recall of the Rey Auditory Verbal Learning Test and for executive functions in HE on the phonological fluency test. MCI and HE participants maintained these effects at follow-up. MCI and mAD participants also showed a significant effect of the training on the Mini-mental state examination scale. Participants with mAD showed more stable instrumental activities of daily living during the training versus the rest period. Conclusions: Our results corroborate the positive effect of pb-CT and its maintenance primarily on memory in HE and MCI participants that did not seem to be potentiated by RT. Moreover, our results are very promising for the mAD participants. [ABSTRACT FROM AUTHOR]