Altered Calcium Permeability of AMPA Receptor Drives NMDA Receptor Inhibition in the Hippocampus of Murine Obesity Models

Evidence has accumulated that higher consumption of high-fat diets (HFDs) during the juvenile/adolescent period induces altered hippocampal function and morphology; however, the mechanism behind this phenomenon remains elusive. Using high-resolution structural imaging combined with molecular and functional interrogation, a murine model of obesity treated with HFDs for 12 weeks after weaning mice was shown to change in the glutamate-mediated intracellular calcium signaling and activity, including further selective reduction of gray matter volume in the hippocampus associated with memory recall disturbance. Dysregulation of intracellular calcium concentrations was restored by a non-competitive α-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR) antagonist, followed by normalization of hippocampal volume and memory recall ability, indicating that AMPARs may serve as an attractive therapeutic target for obesity-associated cognitive decline.

Real and Imagined Smellscapes

The smellscape is the olfactory environment as perceived and understood, consisting of odours and scents from multiple smell sources. To what extent can audiovisual information evoke the smells of a real, complex, and multimodal environment? To investigate smellscape imagination, we compared results from two studies. In the first, onsite participants (N = 15) made a sensory walk through seven locations of an open-air market. In the second, online participants (N = 53) made a virtual walk through the same locations reproduced with audio and video recordings. Responses in the form of free-form verbal annotations, ratings with semantic scales, and a ‘smell wheel’, were analysed for environmental quality, smell source type and strength, and hedonic tone. The degree of association between real and imagined smellscapes was measured through canonical correlation analysis. Hedonic tone, as expressed through frequency counts of keywords in free-form annotations was significantly associated, suggesting that smell sources might generally be correctly inferred from audiovisual information, when such imagination is required. On the other hand, onsite ratings of olfactory quality were not significantly associated with online ratings of audiovisual reproductions, when participants were not specifically asked to imagine smells. We discuss findings in the light of cross-modal association, categorisation, and memory recall of smells.

“It’s not rocket science” and “It’s not brain surgery”—“It’s a walk in the park”: prospective comparative study

Objective To compare cognitive testing scores in neurosurgeons and aerospace engineers to help settle the age old argument of which phrase—“It’s not brain surgery” or “It’s not rocket science”—is most deserved. Design International prospective comparative study. Setting United Kingdom, Europe, the United States, and Canada. Participants 748 people (600 aerospace engineers and 148 neurosurgeons). After data cleaning, 401 complete datasets were included in the final analysis (329 aerospace engineers and 72 neurosurgeons). Main outcome measures Validated online test (Cognitron’s Great British Intelligence Test) measuring distinct aspects of cognition, spanning planning and reasoning, working memory, attention, and emotion processing abilities. Results The neurosurgeons showed significantly higher scores than the aerospace engineers in semantic problem solving (difference 0.33, 95% confidence interval 0.13 to 0.52). Aerospace engineers showed significantly higher scores in mental manipulation and attention (−0.29, −0.48 to −0.09). No difference was found between groups in domain scores for memory (−0.18, −0.40 to 0.03), spatial problem solving (−0.19, −0.39 to 0.01), problem solving speed (0.03, −0.20 to 0.25), and memory recall speed (0.12, −0.10 to 0.35). When each group’s scores for the six domains were compared with those in the general population, only two differences were significant: the neurosurgeons’ problem solving speed was quicker (mean z score 0.24, 95% confidence interval 0.07 to 0.41) and their memory recall speed was slower (−0.19, −0.34 to −0.04). Conclusions In situations that do not require rapid problem solving, it might be more correct to use the phrase “It’s not brain surgery.” It is possible that both neurosurgeons and aerospace engineers are unnecessarily placed on a pedestal and that “It’s a walk in the park” or another phrase unrelated to careers might be more appropriate. Other specialties might deserve to be on that pedestal, and future work should aim to determine the most deserving profession.

Reminiscence groupwork and autobiographical memory as part of meaningful activities

The current paper describes a reminiscence group activity session held as part of meaningful activities engagement for older adults. Topics of reminiscence included both autobiographical memories and memories of broader historical events from the past. Participants included those with memory impairment and those without, and participants with healthy memory were helpful in prompting memories in participants with memory impairment. Semantic and episodic autobiographical memory were assessed at baseline and following the end of both group activities, using the Episodic Autobiographical Memory Interview (EAMI) and quality of life was assessed using the Quality of Life AD-scale (QOL-AD). The reminiscence intervention did not significantly affect autobiographical memory recall or quality of life. However, oral reminiscence was reported to have increased outside of the reminiscence sessions.

No evidence that LSD microdosing affects recall or the balance between distracter resistance and updating

The effect of low doses (<=20 μg) of LSD on working memory, in the absence of altered states of consciousness, remain largely unexplored. Given its possible effects on serotonin 5-HT2A receptors and dopaminergic signalling, it could be hypothesised that LSD microdoses modulate working memory recall. Moreover, in line with computational models, LSD microdoses could exert antagonistic effects on distracter resistance and updating. Here, we tested this hypothesis in a randomised double-blind, placebo-controlled study comparing three different LSD microdoses (5 μg, 10μg and 20μg) with placebo. After capsule administration, participants performed a modified delay-match-to-sample (DMTS) dopamine-sensitive task. The standard DMTS task was modified to include novel items in the delay period between encoding and probe. These novel items either had to be ignored or updated into working memory. There was no evidence that LSD microdoses affected the accuracy or efficiency of working memory recall and there was no evidence for differential effects on ignoring or updating. Due to the small sample of participants, these results are preliminary and larger studies are required to establish whether LSD microdoses affect short-term recall.

Investigating Sequential and Simultaneous Changes in Trajectories of Cognitive Decline and Depressive Symptoms

Background. The role of depression as risk factor or early symptom of cognitive decline and dementia is still debated. Exploiting longitudinal trajectories of memory recall in a large European sample, we sought to better understand the nature of simultaneous versus sequential changes in depressive symptoms alongside memory recall at older ages. Method. A total of 4,865 respondents to the SHARE survey, mean age at t1 61.5 years (SD = 7.53), completed the EURO-D depression scale and a delayed recall task across six waves spanning ~13 years. We applied k-means clustering to distinguish trajectories of depressive symptoms and delayed recall. Clusters indicating depressive and recall trajectories were included in logistic regressions to assess likelihood of parallel versus sequential change, controlling for age, gender, employment status and education. Results. Analyses revealed six distinct trajectories each for depressive symptoms and delayed recall. Visual inspections indicated that only declining recall trajectories showed increases in depressive symptoms, occurring simultaneously rather than sequentially. Using grouped declining recall trajectories as outcome, the low-increasing depressive symptoms trajectory was associated with cognitive decline (OR = 1.52 [1.11, 2.06]), whereas the stable-high depressive symptoms trajectory was associated with cognitive decline in respondents aged 60-69 years (OR = 1.78 [1.01, 3.16]). Discussion. Distinguishing trajectories in depression and recall incorporates longitudinal information able to further elucidate relationships between depression and cognition. While the findings suggest depression as a co-morbidity, attention needs to be given to a comparatively small high-stable depressive symptoms trajectory group with elevated risk of cognitive decline in their 60s.

Content Development for a Virtual Social Engagement Intervention

Video technology has the potential to provide older adults with socially and cognitively engaging activities for in-home participation. We are exploring use of OneClick.chat, a video technology platform, to present older adults with and without mild cognitive impairment opportunities for engagement. In collaboration with iN2L we have developed events that will facilitate conversations that do not rely on episodic memory, cover a range of topics, and represent different cultures and interests. We selected event topics that were positive, socially and cognitively engaging, and included a range of pictures based on our previous research. Events were carefully controlled for length of presentation, picture type, and readability. Discussion questions related to the events were designed to stimulate engaging conversations through open-ended questions and to not burden memory recall or enforce stereotypes. Our work highlights potential future avenues for researchers and home and community-based organizations to use technology to promote social engagement.

Negative Emotion Reduces Visual Working Memory Recall Variability: A Meta-analytical Review

Negative emotion is often hypothesized to trigger a more deliberate processing mode.This effect can manifest as increased precision of information maintained in working memory (WM) captured by reduced WM recall variability. However, some recent evidence shows that WM representations are immune to any emotional influences. Here, we meta-analyze existing evidence based on data from 13 experiments across 491 participants who performed a delay estimation WM task under negative and neutral emotions. We find that negative emotion modestly reduces WM recall variability and increases recall failures relative to the neutral condition. These effects are moderated by participants’ self-report negative experiences during emotion induction. Collectively, these data suggest that negative emotion influences how muchand how well one can remember in WM.