Correlation Between Amygdala Nuclei Volumes and Memory in Cognitively Normal Adults Carrying the ApoE ε3/ε3 Allele

The amygdala is known to be related to cognitive function. In this study, we used an automated approach to segment the amygdala into nine nuclei and evaluated amygdala and nuclei volumetric changes across the adult lifespan in subjects carrying the apolipoprotein E (ApoE) ε3/ε3 allele, and we related those changes to memory function alteration. We found that except the left medial nucleus (Me), whose volume decreased in the old group compared with the middle-early group, all other nuclei volumes presented a significant decline in the old group compared with the young group. Left accessory basal nucleus (AB) and left cortico-amygdaloid transition area (CAT) volumes were also diminished in the middle-late group. In addition, immediate memory recall is impaired by the process of aging, whereas delayed recall and delayed recognition memory functions were not significantly changed. We found significant positive correlations between immediate recall scores and volumes of the bilateral basal nucleus (Ba), AB, anterior amygdaloid area (AAA), CAT, whole amygdala, left lateral nucleus (La), left paralaminar nucleus (PL), and right cortical nucleus (Co). The results suggest that immediate recall memory decline might be associated with volumetric reduction of the amygdala and its nuclei, and the left AB and left CAT might be considered as potential imaging biomarkers of memory decline in aging.

Xerophthalmia with secondary malabsorption syndrome in a young lady

Delayed recognition and treatment of vitamin A deficiency (VAD) in adults leads to devastating complications. A 24-year-old woman presented with diarrhea, malaise, and shortness of breath. Her medical history included blunt abdominal trauma for which, she had bowel resection surgery and revision surgery within a year of the last surgery at the age of 8 years. She had difficulty in night vision and dry eyes. The best-corrected visual acuity was 6/18 in the BE. On slit-lamp examination in the both eyes (BE), the conjunctiva was thick, dry-looking with wrinkling, and the cornea had diffused superficial punctate keratitis and in the left eye, there was corneal xerosis of 1.5 × 1.5 mm. Tear film breakup time was 0-s in the BE. Schirmer's were 30 mm BE. The rest of the ocular examination was within normal limits. A clinical diagnosis of xerophthalmia secondary to malabsorption was made and treated with systemic vitamin A and intense lubrication. With time, ophthalmic conditions improved, but she died due to poor general wellbeing and repeated hospital-acquired infections. The infrequent presentation of VAD in adults and the unusual etiology in this patient make this case interesting, whereas its potentially devastating consequences highlight the importance of its early recognition, treatment, and regular follow up needed by both patient and physician in the community (general practitioner and ophthalmologists) for the prevention of VAD complications and poor prognosis.

Hungarian Structural Focus: Accessibility to Focused Elements and Their Alternatives in Working Memory and Delayed Recognition Memory

The present work investigates the memory accessibility of linguistically focused elements and the representation of the alternatives for these elements (i.e., their possible replacements) in Working Memory (WM) and in delayed recognition memory in the case of the Hungarian pre-verbal focus construction (preVf). In two probe recognition experiments we presented preVf and corresponding focusless neutral sentences embedded in five-sentence stories. Stories were followed by the presentation of sentence probes in one of three conditions: (i) the probe was identical to the original sentence in the story, (ii) the focused word (i.e., target) was replaced by a semantically related word and (iii) the target word was replaced by a semantically unrelated but contextually suitable word. In Experiment 1, probes were presented immediately after the stories measuring WM performance, while in Experiment 2, blocks of six stories were presented and sentences were probed with a 2-minute delay measuring delayed recognition memory performance. Results revealed an advantage of the focused element in immediate but not in delayed retrieval. We found no effect of sentence type on the recognition of the two different probe types in WM performance. However, results pertaining to the memory accessibility of focus alternatives in delayed retrieval showed an interference effect resulting in a lower memory performance. We conclude that this effect is indirect evidence for the enhanced activation of focus alternatives. The present work is novel in two respects. First, no study has been conducted on the memory representation of focused elements and their alternatives in the case of the structurally marked Hungarian pre-verbal focus construction. Second, to our knowledge, this is the first study that investigates the focus representation accounts for WM and delayed recognition memory using the same stimuli and same measured variables. Since both experiments used exactly the same stimulus set, and they only differed in terms of the timing of recognition probes, the principle of ceteris paribus fully applied with respect to how we addressed our research question regarding the two different memory systems.

Delayed Recognition: A Co-Citation Perspective

A Sleeping Beauty is a publication that is apparently unrecognized by citation for some period of time before experiencing a burst of recognition. Various reasons, including resistance to new ideas, have been attributed to such delayed recognition. We study this phenomenon in the special case of co-citations, which represent new ideas generated through the combination of existing ones. Using relatively stringent selection criteria derived from the work of others, we analyze a very large dataset of over 940 million unique co-cited article pairs, and identify 1,196 cases of delayed co-citations. We further classify these 1,196 cases with respect to amplitude, rate of citation, and disciplinary origin.

Transcutaneous Vagus Nerve Stimulation Does Not Affect Verbal Memory Performance in Healthy Volunteers

Introduction

Invasive vagus nerve stimulation (VNS) improves word recognition memory in patients with epilepsy. Recent studies with transcutaneous VNS (tVNS) have also shown positive effects on various subdomains of cognitive functioning in healthy volunteers. In this randomized, controlled, crossover study, we investigated the effect of tVNS on a word recognition memory paradigm in healthy volunteers to further investigate the potential of tVNS in the treatment of cognitive disorders.

Methods

We included 41 healthy participants aged between 18 and 30 years (young age group) and 24 healthy participants aged between 45 and 80 years (older age group). Each participant completed a word recognition memory paradigm during three different conditions: true tVNS, sham, and control. During true tVNS, stimulation was delivered at the cymba conchae. Sham stimulation was delivered by stimulating the earlobe. In the control condition, no stimulation was given. In each condition, participants were asked to remember highlighted words from three test paragraphs. Accuracy scores were calculated for immediate recall after each test paragraph and for delayed recognition at the end of the paradigm. We hypothesized that highlighted words from paragraphs in the true tVNS condition would be more accurately recalled and/or recognized compared to highlighted words from paragraphs in the sham or control condition.

Results

In this randomized study, tVNS did not affect the accuracy scores for immediate recall or delayed recognition in both age groups. The younger group showed significantly higher accuracy scores than the older group. The accuracy scores improved over time, and the most recently learned words were better recognized. Participants rated true tVNS as significantly more painful; however, pain was not found to affect accuracy scores.

Conclusion

In this study, tVNS did not affect verbal memory performance in healthy volunteers. Our results could not replicate the positive effects of invasive VNS on word recognition memory in epilepsy patients. Future research with the aim of improving cognitive function should focus on the rational identification of optimized and individualized stimulation settings primarily in patients with cognitive deficits.

Spatio-Temporal Neural Changes After Task-Switching Training in Old Age

In the present study, we aimed at examining selective neural changes after task-switching training in old age by not only considering the spatial location but also the timescale of brain activation changes (i.e., sustained/block-related or transient/trial-related timescales). We assigned a sample of 50 older adults to a task-switching training or an active single-task control group. We administered two task paradigms, either sensitive to transient (i.e., a context-updating task) or sustained (i.e., a delayed-recognition working-memory task) dynamics of cognitive control. These dynamics were captured by utilizing an appropriate event-related or block-related functional magnetic resonance imaging design. We captured selective changes in task activation during the untrained tasks after task-switching training compared to an active control group. Results revealed changes at the neural level that were not evident from only behavioral data. Importantly, neural changes in the transient-sensitive context updating task were found on the same timescale but in a different region (i.e., in the left inferior parietal lobule) than in the task-switching training task (i.e., ventrolateral PFC, inferior frontal junction, superior parietal lobule), only pointing to temporal overlap, while neural changes in the sustained-sensitive delayed-recognition task overlapped in both timescale and region with the task-switching training task (i.e., in the basal ganglia), pointing to spatio-temporal overlap. These results suggest that neural changes after task-switching training seem to be critically supported by the temporal organization of neural processing.

Defining and identifying Sleeping Beauties in science

A Sleeping Beauty (SB) in science refers to a paper whose importance is not recognized for several years after publication. Its citation history exhibits a long hibernation period followed by a sudden spike of popularity. Previous studies suggest a relative scarcity of SBs. The reliability of this conclusion is, however, heavily dependent on identification methods based on arbitrary threshold parameters for sleeping time and number of citations, applied to small or monodisciplinary bibliographic datasets. Here we present a systematic, large-scale, and multidisciplinary analysis of the SB phenomenon in science. We introduce a parameter-free measure that quantifies the extent to which a specific paper can be considered an SB. We apply our method to 22 million scientific papers published in all disciplines of natural and social sciences over a time span longer than a century. Our results reveal that the SB phenomenon is not exceptional. There is a continuous spectrum of delayed recognition where both the hibernation period and the awakening intensity are taken into account. Although many cases of SBs can be identified by looking at monodisciplinary bibliographic data, the SB phenomenon becomes much more apparent with the analysis of multidisciplinary datasets, where we can observe many examples of papers achieving delayed yet exceptional importance in disciplines different from those where they were originally published. Our analysis emphasizes a complex feature of citation dynamics that so far has received little attention, and also provides empirical evidence against the use of short-term citation metrics in the quantification of scientific impact.

Expectations of Task Demands Dissociate Working Memory and Long-Term Memory Systems

Many aspects of the complex relationship between working memory (WM) and long-term memory (LTM) remain unclear. Here, we manipulated task demands on a brief delayed-recognition paradigm to reveal behavioral and neural dissociations between these systems. Variations from a Baseline task included 3 challenges: increased delay duration, distraction during maintenance, and more closely matched memory probes, which were presented in behavioral experiments and during functional magnetic resonance imaging. Each of the challenges resulted in a significant decline in WM accuracy, and interestingly, a concurrent improvement in incidental LTM. Neural data revealed that, in task blocks, when participants anticipated, and then experienced, increased demands, they engaged medial temporal lobe (MTL) regions more during both the encoding and delay periods. Overall, these results indicate that distinct memory systems are recruited based on anticipated demands of a memory task, and MTL involvement underlies the observed dissociation between WM and LTM performance.

Short-term retention of relational memory in amnesia revisited: accurate performance depends on hippocampal integrity

Traditionally, it has been proposed that the hippocampus and adjacent medial temporal lobe cortical structures are selectively critical for long-term declarative memory, which entails memory for inter-item and item-context relationships. Whether the hippocampus might also contribute to short-term retention of relational memory representations has remained controversial. In two experiments, we revisit this question by testing memory for relationships among items embedded in scenes using a standard working memory trial structure in which a sample stimulus is followed by a brief delay and the corresponding test stimulus. In each experimental block, eight trials using different exemplars of the same scene were presented. The exemplars contained the same items but with different spatial relationships among them. By repeating the pictures across trials, any potential contributions of item or scene memory to performance were minimized, and relational memory could be assessed more directly than has been done previously. When test displays were presented, participants indicated whether any of the item-location relationships had changed. Then, regardless of their responses (and whether any item did change its location), participants indicated on a forced-choice test, which item might have moved, guessing if necessary. Amnesic patients were impaired on the change detection test, and were frequently unable to specify the change after having reported correctly that a change had taken place. Comparison participants, by contrast, frequently identified the change even when they failed to report the mismatch, an outcome that speaks to the sensitivity of the change specification measure. These results confirm past reports of hippocampal contributions to short-term retention of relational memory representations, and suggest that the role of the hippocampus in memory has more to do with relational memory requirements than the length of a retention interval.