Mindwandering propensity modulates episodic memory consolidation

Research into strategies that can combat episodic memory decline in healthy older adults has gained widespread attention over the years. Evidence suggests that a short period of rest immediately after learning can enhance memory consolidation, as compared to engaging in cognitive tasks. However, a recent study in younger adults has shown that post-encoding engagement in a working memory task leads to the same degree of memory consolidation as from post-encoding rest. Here, we tested whether this finding can be extended to older adults. Using a delayed recognition test, we compared the memory consolidation of word–picture pairs learned prior to 9 min of rest or a 2-Back working memory task, and examined its relationship with executive functioning and mindwandering propensity. Our results show that (1) similar to younger adults, memory for the word–picture associations did not differ when encoding was followed by post-encoding rest or 2-Back task and (2) older adults with higher mindwandering propensity retained more word–picture associations encoded prior to rest relative to those encoded prior to the 2-Back task, whereas participants with lower mindwandering propensity had better memory performance for the pairs encoded prior to the 2-Back task. Overall, our results indicate that the degree of episodic memory consolidation during both active and passive post-encoding periods depends on individual mindwandering tendency

3D negative electrode stacks for integrated all-solid-state lithium-ion microbatteries

The deposition feasibility and electrochemical evaluation of highly structured negative electrode stacks for 3D-integrated batteries is demonstrated. The stacks comprise a TiN thin film, serving as both current collector and Li-barrier layer, covered by a polycrystalline Si (poly-Si) thin film as electrode material. In comparison with planar films, these poly-Si films present a storage capacity increase of about 5x for the highest pore aspect ratio electrodes. The step coverage of poly-Si can be considerably improved by growing TiN and poly-Si into wide trenches. This results in much smoother poly-Si films and significantly improved step coverage. Further optimization of the trench dimensions should result in poly-Si films with a Li-storage capacity increase of more than one order of magnitude with respect to planar films

Are visual working memory and episodic memory distinct processes? Insight from stroke patients by lesion-symptom mapping

Working memory and episodic memory are two different processes, although the nature of their interrelationship is debated. As these processes are predominantly studied in isolation, it is unclear whether they crucially rely on different neural substrates. To obtain more insight in this, 81 adults with sub-acute ischemic stroke and 29 elderly controls were assessed on a visual working memory task, followed by a surprise subsequent memory test for the same stimuli. Multivariate, atlas- and track-based lesion-symptom mapping (LSM) analyses were performed to identify anatomical correlates of visual memory. Behavioral results gave moderate evidence for independence between discriminability in working memory and subsequent memory, and strong evidence for a correlation in response bias on the two tasks in stroke patients. LSM analyses suggested there might be independent regions associated with working memory and episodic memory. Lesions in the right arcuate fasciculus were more strongly associated with discriminability in working memory than in subsequent memory, while lesions in the frontal operculum in the right hemisphere were more strongly associated with criterion setting in subsequent memory. These findings support the view that some processes involved in working memory and episodic memory rely on separate mechanisms, while acknowledging that there might also be shared processes. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00429-021-02281-0

Nucleation and growth of Pt atomic layer deposition on Al2O3 substrates using (methylcyclopentadienyl)-trimethyl platinum and O2 plasma

The nucleation and growth of Pt atomic layer deposition (ALD) on Al2O3 substrates was studied using (methylcyclopentadienyl)-trimethyl platinum (MeCpPtMe3) and O2 plasma as the reactants. The nucleation of Pt ALD was examined on Al2O3 ALD substrates at 300¿°C using a variety of techniques including spectroscopic ellipsometry, x-ray reflectivity, x-ray photoelectron spectroscopy, and scanning electron microscopy. These techniques revealed that Pt ALD does not nucleate and grow immediately on the Al2O3 ALD substrates. There was negligible Pt ALD during the first 38 ALD cycles. The Pt ALD growth rate then increased substantially during the next 12 ALD cycles. Subsequently, the Pt ALD growth rate reached a steady state linear growth regime for >50 ALD cycles. These measurements suggest that the Pt ALD first forms a number of nanoclusters that grow slowly during the first 38 ALD cycles. These islands then merge during the next 12 cycles and yield a steady state Pt ALD growth rate of ~0.05 nm/cycle for >50 ALD cycles. The Pt ALD film at the onset of the steady state linear growth regime was approximately 2–3 nm in thickness. However, the SEM images of these Pt ALD films appeared corrugated and wormlike. These films also had a density that was only 50–70% of bulk Pt. Film densities that were consistent with bulk Pt were not observed until after >100 ALD cycles when the Pt ALD films appeared much smoother and were 4–5 nm in thickness. The Pt ALD nucleation rate could be enhanced somewhat using different O2 plasma parameters

Performance of the EQ-5D and the EQ-5D+C in elderly patients with cognitive impairments

<p>Abstract</p> <p>Background</p> <p>The EQ-5D is a reliable tool for measuring Health-Related Quality of Life (HRQoL). However, concern has been expressed that it may ignore elements of HRQoL, particularly cognition. In response to this concern, the EQ-5D has been extended with a cognitive dimension (EQ-5D+C). The aim of this study was to compare the performance of the EQ-5D and the EQ-5D+C in elderly patients with cognitive impairments by assessing their construct validity and responsiveness.</p> <p>Methods</p> <p>Data from the MEDICIE study (n = 196) were used, in which all questionnaires were rated by proxies.</p> <p>Results</p> <p>Regarding construct validity, we found similar correlations between the EQ-5D and the Mini Mental State Examination (MMSE) and between the EQ-5D+C and the MMSE. Furthermore, both the EQ-5D and the EQ-5D+C were responsive to changes in the MMSE, with the EQ-5D performing slightly better.</p> <p>Conclusion</p> <p>We conclude that the EQ-5D performs well for evaluating HRQoL in a population with cognitive impairments. Based on the results of this explorative study, it does not seem necessary to adjust the current classification system by adding a cognitive dimension. However, in order to compare both instruments regarding utility values, it is necessary to develop a new scoring algorithm for the EQ-5D+C by conducting a general population study. Considering the explorative nature of this study, it is recommended that more aspects of the validity of both the EQ-5D and the EQ-5D+C are explored in patients with cognitive impairments using a more tailored study design.</p

Non-interfering effects of active post-encoding tasks on episodic memory consolidation in humans

So far, studies that investigated interference effects of post-learning processes on episodic memory consolidation in humans have used tasks involving only complex and meaningful information. Such tasks require reallocation of general or encoding-specific resources away from consolidation-relevant activities. The possibility that interference can be elicited using a task that heavily taxes our limited brain resources, but has low semantic and hippocampal related long-term memory processing demands, has never been tested. We address this question by investigating whether consolidation could persist in parallel with an active, encoding-irrelevant, minimally semantic task, regardless of its high resource demands for cognitive processing. We distinguish the impact of such a task on consolidation based on whether it engages resources that are: (1) general/executive, or (2) specific/overlapping with the encoding modality. Our experiments compared subsequent memory performance across two post-encoding consolidation periods: quiet wakeful rest and a cognitively demanding n-Back task. Across six different experiments (total N = 176), we carefully manipulated the design of the n-Back task to target general or specific resources engaged in the ongoing consolidation process. In contrast to previous studies that employed interference tasks involving conceptual stimuli and complex processing demands, we did not find any differences between n-Back and rest conditions on memory performance at delayed test, using both recall and recognition tests. Our results indicate that: (1) quiet, wakeful rest is not a necessary prerequisite for episodic memory consolidation; and (2) post-encoding cognitive engagement does not interfere with memory consolidation when task-performance has minimal semantic and hippocampally-based episodic memory processing demands. We discuss our findings with reference to resource and reactivation-led interference theorie

Atomic layer deposition of Ru from CpRu(CO2)Et using O2 gas and O2 plasma

The metalorganic precursor cyclopentadienylethyl(dicarbonyl)ruthenium (CpRu(CO)2Et) was used to develop an atomic layer deposition (ALD) process for ruthenium. O2 gas and O2 plasma were employed as reactants. For both processes, thermal and plasma-assisted ALD, a relatively high growth-per-cycle of - 1 Å was obtained. The Ru films were dense and polycrystalline, regardless of the reactant, yielding a resistivity of - 16 µO¿cm. The O2 plasma not only enhanced the Ru nucleation on the TiN substrates but also led to an increased roughness compared to thermal ALD