Long-term Memory Research Articles

Effectiveness and Safety of mRNA Vaccines in the Therapy of Glioblastoma

Glioblastoma (GBM) is the most common and most malignant primary brain tumor, presenting significant treatment challenges due to its heterogeneity, invasiveness, and resistance to conventional therapies. Despite aggressive treatment protocols, the prognosis remains poor, with a median survival time of approximately 15 months. Recent advancements in mRNA vaccine technology, particularly the development of lipid nanoparticles (LNPs), have revitalized interest in mRNA-based therapies. These vaccines offer unique advantages, including rapid production, personalization based on tumor-specific mutations, and a strong induction of both humoral and cellular immune responses. mRNA vaccines have demonstrated potential in preclinical models, showing significant tumor regression and improved survival rates. Early-phase clinical trials have indicated that mRNA vaccines are safe and can induce robust immune responses in GBM patients. Combining mRNA vaccines with other immunotherapeutic approaches, such as checkpoint inhibitors, has shown synergistic effects, further enhancing their efficacy. However, challenges such as optimizing delivery systems and overcoming the immunosuppressive tumor microenvironment remain. Future research should focus on addressing these challenges and exploring combination therapies to maximize therapeutic benefits. Large-scale, randomized clinical trials are essential to validate the efficacy and safety of mRNA vaccines in GBM therapy. The potential to reshape the tumor microenvironment and establish long-term immunological memory underscores the transformative potential of mRNA vaccines in cancer immunotherapy.

Measuring the Effects of Cognitive Capacity on Sentence Comprehension: Evidence From Elementary School-Age Children.

Our aim was to (a) develop a sentence comprehension measure that distinguished between cognitive capacity and syntactic knowledge in school-age children and (b) examine the relationship between comprehension performance and cognitive variables (working memory capacity and retrieval from long-term memory). We developed and administered a picture selection sentence comprehension task to 122 school-age children representing varied cognitive abilities. We evaluated comprehension accuracy and response time in two syntactically identical conditions but with different cognitive demands incorporated in picture foils-one with low demand using superfluous adjectives and another with high demand using contrastive adjectives. Children also completed tasks measuring working memory capacity and long-term memory retrieval. Comprehension accuracy was significantly lower, and response times were longer in the high-cognitive demand condition compared to the low-demand condition. Errors frequently involved incorrect attribute selection in the high-demand condition that included contrastive adjectives in picture foils, while reversal errors prevailed in the low-demand condition, which included superfluous adjectives. Accuracy correlated positively with the memory variables. Hierarchical regression analysis showed that after adjusting for comprehension in the low-cognitive demand condition (38.60% variance), memory variables accounted for 4.50% additional variance in the high-demand condition with only working memory capacity as the unique predictor. The significant role of working memory capacity in comprehending sentences with high cognitive demand indicated the recruitment of active attention and verbal rehearsal. Data support the newly developed measure's potential for assessing cognitive skills integral to sentence comprehension in school-age children. https://doi.org/10.23641/asha.26767063.

Cognitive behavioral phenotyping of DSCAM heterozygosity as a model for autism spectrum disorder.

It is estimated that 1 in 36 children are affected by autism spectrum disorder (ASD) in the United States, which is nearly a twofold increase from a decade ago. Recent genetic studies have identified de novo loss-of-function (dnLoF) mutations in the Down Syndrome Cell Adhesion Molecule (DSCAM) as a strong risk factor for ASD. Previous research has shown that DSCAM ablation confers social interaction deficits and perseverative behaviors in mouse models. However, it remains unknown to what extent DSCAM underexpression captures the full range of behaviors, specifically cognitive phenotypes, presented in ASD. Here, we conducted a comprehensive cognitive behavioral phenotyping which revealed that loss of one copy of DSCAM, as in the DSCAM2J+/-, that is, DSCAM heterozygous mice, displayed hyperactivity, increased anxiety-like behavior, and motor coordination deficits. Additionally, hippocampal-dependent learning and memory was affected, including impairments in working memory, long-term memory, and contextual fear learning. Interestingly, implicit learning processes remained intact. Therefore, DSCAM LoF produces autistic-like behaviors that are similar to those observed in human cases of ASD. These findings further support a role for DSCAM dnLoF mutations in ASD and suggest DSCAM2J+/- as a suitable model for ASD research.

EphrinB2 in excitatory neurons and astrocytes in the basolateral amygdala controls long-term fear memory formation

EphrinB2 regulates synaptic transmission and morphology however its role in memory formation is unknown. Here we show that deleting ephrinB2 from excitatory neurons in the basolateral amygdala (BLA) of male mice impairs long-term (LTM), but not short-term (STM), fear memory formation. Deleting ephrinB2 from astrocytes in the BLA impairs fear LTM but not STM. Removing ephrinB2 from astrocytes in the BLA reduces the level of the excitatory amino acid transporter 1 (EAAT1) in these cells. Inhibiting EAAT1 activity in the BLA during fear conditioning, by its specific inhibitor UCPH-101, impairs fear LTM showing that EAAT1 in the BLA is needed for fear LTM formation. The administration of ephrinB2 into the BLA during fear conditioning training enhances fear LTM. Moreover, ephrinB2 increases the ability of fear conditioning to activate cells in the BLA as detected by c-Fos labeling. EphrinB2 therefore determines the threshold for fear memory formation. In contrast to mature neurons, we show that ephrinB2 in neural stem cells (NSCs) is not needed for fear LTM. Our study shows that ephrinB2 in the BLA determines the strength of long-term memory consolidation.

Precise In Situ Delivery of a Photo-enhanceable Inflammasome-Activating Nanovaccine Activates Anti-cancer Immunity.

A variety of state-of-the-art nanovaccines (NVs) combined with immunotherapies have recently been developed to treat malignant tumors, showing promising results. However, immunosuppression in the tumor microenvironment (TME) restrains cytotoxic T cells infiltration and limits the efficacy of immunotherapies in solid tumors. Therefore, tactics for enhancing antigen cross-presentation and reshaping the TME need to be explored to enhance the activity of NV. Here, we developed a photo-enhanceable inflammasome-activating NV (PIN) to achieve precise in situ delivery of a tumor antigen and a hydrophobic small molecule activating the NLRP3-inflammasome pathway. Near-infrared light irradiation promoted PIN accumulation in tumor sites through photo-triggered charge reversal of the nanocarrier. Systematic PIN administration facilitated intratumoral NLRP3 inflammasome activation and antigen cross-presentation in antigen-presenting cells upon light irradiation at tumor sites. Furthermore, PIN treatment triggered immune responses by promoting the production of proinflammatory cytokines and activated of anti-tumor immunity without significant systematic toxicity. Importantly, the PIN enhanced the efficacy of immune checkpoint blockade and supported the establishment of long-term immune memory in mouse models of melanoma and hepatocellular carcinoma. Collectively, this study reports a safe and efficient photoresponsive system for co-delivery of antigens and immune modulators into tumor tissues with promising therapeutic potential.

Persistent resampling of external information despite 25 repetitions of the same visual search templates.

We commonly load visual working memory minimally when to-be-remembered information remains available in the external world. In visual search, this is characterised by participants frequently resampling previously encoded templates, which helps minimize cognitive effort and improves task performance. If all search templates have been rehearsed many times, they should become strongly represented in memory, possibly eliminating the benefit of reinspections. To test whether repetition indeed leads to less resampling, participants searched for sets of 1, 2, and 4 continuously available search templates. Critically, each unique set of templates was repeated 25 trials consecutively. Although the number of inspections and inspection durations initially decreased strongly when a template set was repeated, behaviour largely stabilised between the tenth and last repetition: Participants kept resampling templates frequently. In Experiment 2, participants performed the same task, but templates became unavailable after 15 repetitions. Strikingly, accuracy remained high even when templates could not be inspected, suggesting that resampling was not strictly necessary in later repetitions. We further show that seemingly 'excessive' resampling behaviour had no direct within-trial benefit to speed nor accuracy, and did not improve performance on long-term memory tests. Rather, we argue that resampling was partially used to boost metacognitive confidence regarding memory representations. As such, eliminating the benefit of minimizing working memory load does not eliminate the persistence with which we sample information from the external world - although the underlying reason for resampling behaviour may be different.

Abstract B044: Durable T-cell-mediated anti-tumor immune response to pancreatic cancer cells overexpressing interleukin 6

Abstract Tumor immune resistance contributes to low survivorship in patients with pancreatic ductal adenocarcinoma (PDAC). To understand how tumor-secreted factors might impact anti-tumor immunity, we developed a model of PDAC tumor overexpressing interleukin-6 (IL-6), a known driver of pancreatic tumorigenesis and cancer cachexia, in orthotopically implanted PDAC cancer cells (OT-PDACIL6). This model utilized codon-optimized IL6 to accurately detect tumor cells in the pancreas and distal organs via qPCR. OT-PDACIL6 tumors developed poorly- differentiated, infiltrative carcinomas, which were histologically similar to the PDAC cell line they were derived from (OT-PDACparental). Surprisingly, OT-PDACIL6 tumors were present at 5 days post implantation, but undetectable by histology or qPCR by 10 days post implantation. OT- PDACIL6 and sham mouse survival were equivalent (87.5%) at 76 days post-implantation. OT- PDACparental mortality was 100% at day 13. We concluded that OT-PDACIL6 tumors resolve spontaneously. IL-6 is well-established as a driver of cachexia, and we saw that OT-PDACIL6 tumors induced a rapid cachexia phenotype that began to resolve as the tumor was cleared. Plasma IL-6 levels tracked with tumor burden. At 5 days, plasma IL-6 was 100-fold higher in OT-PDACIL6 mice than in OT-PDACparental mice, but undetectable in OT-PDACIL6 mice after 12 days. We hypothesized that high levels of IL-6 were driving an anti-tumor immune response. To assess changes in tumor immune infiltrate that could lead to tumor clearance, we measured a broad range of immune cells using flow cytometry and immunofluorescent histology. At peak tumor burden, we observed exacerbated splenomegaly, and increased tumor-infiltrating T cells and NK cells in OT-PDACIL6 mice. T regulatory cells were decreased in OT-PDACIL6 tumors. CD4/CD8 antibody-based depletion prevented tumor clearance and significantly decreased survival of OT-PDACIL6 mice, indicating that T cells are necessary for IL-6-driven PDAC tumor clearance. We then tested whether the anti-tumor T cell response was durable using a secondary tumor challenge with PDACparental cells. This revealed that the anti-tumor T cell response elicited by mice bearing OT-PDACIL6 tumors was sufficient to prevent development of OT-PDACparental tumors, likely due to induction of long-term memory T cells during the initial tumor challenge. We assessed the effect of the anti-tumor immune response on metastases and found that PDACIL6 cells were detected by qPCR in lungs of 58% of mice at day 5, and not detected at day 12. We conclude that extremely high levels of tumor-derived IL-6 are sufficient to drive an anti-tumor T cell response that rapidly and durably clears the tumor. The combination of increased tumor-infiltrating T cells and decreased T regulatory cells are likely both important aspects of the immune response observed in OT-PDACIL6 mice. This surprising finding highlights the pleiotropic effects of IL-6, which is known to promote tumorigenesis and cachexia, and yet, in this work, is the driving force underlying tumor clearance. Citation Format: Paige C Arneson-Wissink, Alexandra Q Bartlett, Heike Mendez, Xinxia Zhu, Jessica Dickie, Matthew McWhorter, Peter R Levasseur, Parham Diba, Katelyn T Byrne, Gregory D Scott, Robert Eil, Aaron J Grossberg. Durable T-cell-mediated anti-tumor immune response to pancreatic cancer cells overexpressing interleukin 6 [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr B044.

The effect of sports expertise on the performance of orienteering athletes’ real scene image recognition and their visual search characteristics

As a sport conducted in dynamically changing natural environments, orienteering places high demands on athletes' cognitive processing abilities and visual search efficiency. However, previous studies on orienteering have been primarily limited by the use of fixed stimulus materials on computer screens, which are unable to fully simulate authentic sports scenarios. To better understand the sports expertise of orienteering athletes in terms of their real scene image recognition performance and visual search characteristics, this study recruited 40 orienteering athletes, both experts and novices, as participants. By utilizing eye-tracking technology and setting observation points in real-world scenarios to conduct image recognition task tests, the ecological validity of the experiment was further enhanced. The results showed that the experts demonstrated a high level of accuracy and a short response time, with visual search characteristics including few saccade counts, low fixation frequency, concentrated fixation points, simple and clear fixation paths, and higher visual search efficiency. This study further reveals that long-term specialized training will lead to the formation of a unique cognitive structure related to the specific knowledge and long-term memory required by expert orienteering athletes, thereby promoting the development of expert advantage.

HMGCR Inhibitor Restores Mitochondrial Dynamics by Regulating Signaling Cascades in a Rodent Alzheimer's Disease Model.

Atorvastatin an HMGCR inhibitor may play a role in enhancing spatial and long-term memory and combating anxious behavior deficits induced by Aβ1-42. Behavioral deficit studies, immunoblotting for the antioxidant/apoptotic protein expression, flow cytometry (FACS) for mitochondrial ROS, membrane potential (▲ψm), and histopathological alterations were performed against Aβ1-42 toxicity. Aβ1-42 was infused directly into the brain through i.c.v for the establishment of the AD model. Atorvastatin (ATOR) was administered orally and was used to treat AD in adult male Wistar rats aged between 200 and 250g. We confirmed that ATOR administration significantly attenuates the Aβ1-42-induced cognitive decline targeted mitochondrial-mediated age-dependent disease progression. Nrf2 stabilizes to interact SOD2 antioxidant enzyme, allowing transcriptional activity by the steep increase in ▲ψm and a reduction in ROS by activating mitochondrial superoxide scavenger and Nrf2-dependent pathway. These findings confirmed that ATOR has the potential efficacy to modulate the interference in cognitive decline induced by Aβ1-42.

317 Microbial interventions to improve gut health in neonatal ruminants

Abstract Colonization and establishment of a balanced and healthy gut microbiome during the neonatal period can directly and indirectly influence animals by affecting the development and metabolism, nutrition absorption, barrier and immune functions, and endocrine and neuron transmitter secretions. Therefore, neonatal period represents a crucial window of time in animal’s life that induces long-term developmental and immune memory. Therefore, alterations in the early gut microbial composition and colonization trajectories lead to long-term negative effects on animals’ production and health. While the rapidly developing gut microbial community is affected by various external factors due to its instability, it provides a great opportunity for microbial intervention to alter microbial colonization trajectories and their subsequent impact on gut health. Recent advance research has been successful in restoring altered gut microbial communities by using microbial interventions such as vaginal seeding, fecal microbial transplantation, probiotics, and prebiotics. However, there is a lack of understanding on the long-term effects of these interventions on gut health in neonatal ruminants. Direct fed microbes (live naturally existing microbes that can improve health and production performance) with psychobiotic function (a type of probiotic that affect cognitive and behavioral functions of the host via the gut-brain axis) can be one of the novel microbiome solutions to target and alter the microbiome dysbiosis. The use of direct fed microbes, postbiotics and psychobiotics and their potential implications in improving calf health and productivity leads to a novel solution to the manipulation of the gut microbiome in calves.

Scheduling of Collaborative Vegetable Harvesters and Harvest-Aid Vehicles on Farms

Transporting harvested vegetables in the field or greenhouse is labor-intensive. The utilization of small harvest-aid vehicles can reduce non-productive time for farmers and improve harvest efficiency. This paper models the process of harvesting vegetables in response to non-productive waiting delays caused by the scheduling of harvest-aid vehicles. Taking into consideration harvesting speed, harvest-aid vehicle capacity, and scheduling conflicts, a harvest-aid vehicle scheduling model is constructed to minimize non-production waiting time and coordination costs. Subsequently, to meet the collaborative needs of harvesters, this paper develops a discrete multi-objective Jaya optimization algorithm (DMO-Jaya), which combines an opposition-based learning mechanism and a long-term memory library to obtain scheduling schemes suitable for agricultural environments. Experiments show that the studied model can schedule harvest-aid vehicles without conflicts. Compared to the NSGA-II algorithm and the MMOPSO, the DMO-Jaya algorithm demonstrates a better diversity of solutions, resulting in a shorter non-productive waiting time for harvesters. This research provides a reference model for improving the efficiency of vegetable harvesting and transportation.

B - 80 The Long-Term Memory Sign in Adults Referred for Neuropsychological Evaluation

Abstract Objective We investigated the clinical utility of the newly described long-term memory (LTM) sign in adults referred for neuropsychological evaluation. Individuals with dementia often report short-term episodic memory decline or no memory decline, but rarely report long-term episodic memory decline. The LTM sign refers to patient self-report of long-term episodic memory decline, that is equivalent to/or greater than, subjective short-term episodic memory decline. Method The LTM sign was endorsed on a pre-visit intake form and established during clinical interview in 568 patients (M age = 63, SD = 14.3) referred for neuropsychological evaluation at a large medical center in the Northwest United States. Results In our sample of 568 patients, 79 (14%) reported the LTM sign. In 79 patients with the LTM sign, 45 were diagnosed with a primary psychiatric disorder (57%), 23 were diagnosed with mild neurocognitive disorder (29%), seven had no cognitive or psychiatric diagnosis (9%), and four had dementia (5%). The LTM sign was most common in those with a history of trauma in childhood or adolescence (52/79, 66%) and substance use disorders (50/79, 63%). Conclusions The LTM sign was rare in dementia, but common in those with a current psychiatric diagnosis. These findings support the literature on episodic memory decline in dementia populations and suggests that encoding of early memories and/or retrieval of old memories is negatively impacted by a current psychiatric disorder, traumatic events in childhood and adolescence, and lifetime history of substance use disorder. The LTM sign is a valuable addition to the clinical interview of neuropsychological patients.

B - 108 Sleep Disordered Breathing, Cognition, and Anxiety in Young Adults

Abstract Objective Sleep disordered breathing (SDB) describes abnormal breathing during sleep due to upper airway dysfunction. SDB and anxiety are associated and independently affect cognition. The purpose of this study was to examine these associations among young adults in the domains of executive function, attention, working memory (WM), and long-term memory (LTM). Method Bronx students (N = 49, Mage = 19.8 years (SD = 1.30), female = 65%) were recruited via flyers. SDB risk assessment utilized the Berlin Questionnaire. Cognitive assessment included the Modified Rey Auditory Verbal Learning Test, Trail Making Test A and B, Controlled Oral Word Association Test, and the Cogstate computerized battery (Groton Maze Learning Test, Identification Test, One Back Test, Two Back Test, and Groton Maze Learning Test Recall). Anxiety was assessed with the Depression, Anxiety, and Stress Scales. Individuals in the normal/mild ranges were categorized in the low anxiety group, and individuals in the moderate/severe/extremely severe ranges were categorized in the high anxiety group. Results Anxiety symptoms moderated the relationship between SDB risk and WM. For high anxiety individuals, as SDB risk increased, performance on WM measures decreased (F(1,45) = 6.06, p = 0.02, η2 = 0.12). There was a trend for anxiety symptoms to moderate the relationship between SDB risk and LTM – among high anxiety individuals, as SDB risk increased, performance on LTM decreased (F(1,44) = 4.04, p = 0.05, η2 = 0.084). Conclusion For young adults, anxiety symptoms moderated the relationships between SDB and WM and between SDB and LTM, suggesting that mild levels of anxiety may have a beneficial effect on the relationship between SDB and cognition, while more severe anxiety may worsen that relationship.

Categorically distinct subsets allow flexible memory selection in hybrid search.

In many everyday situations, we search our visual surroundings for any one of many memorized items held in memory, a process termed hybrid search. In some cases, only a portion of the memorized mental list is relevant within a specific visual context, thus, restricting memory search to the relevant subset would be desirable. Previous research had shown that participants largely fail to "partition" memory into several distinct subsets, on a trial-by-trial basis. However, given the known role of semantic content in long-term memory organization, we hypothesized that semantically defined subset categories might serve as a more powerful means for flexible memory selection in dynamic hybrid search situations. Experiment 1 revealed that, indeed, semantic characteristics (i.e., object category), but not perceptual features (e.g., arbitrary color), can provide a firm basis for flexible memory partitioning. Experiments 2 and 3 further showed that such memory partitioning is costless and is independent of the nature of the surrounding visual distractors (i.e., a categorically homogeneous or heterogeneous display). These findings demonstrate that confining one's memory search to a currently relevant subset of items is highly effective when the different memory subsets are defined by clear semantic categories. The results underscore the importance of conceptual information in the organization of activated long-term memory and in forming the basis for a flexible trial-by-trial memory selection. Our findings further highlight the relationship between visual search and memory search, and they may shed light on the processes contributing to a successful construction of bounded episodes in long-term memory. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

B - 103 Chronic Stress and Smoking Moderate the Relation between Hippocampal Volume and Long-Term Memory in Older Hispanic Adults

Abstract Objective We evaluated how self-reported chronic stress and lifetime smoking behavior moderates the relation between hippocampal volume and memory. Method 841 Hispanic adults (mean age = 63.12 years, SD = 8.03; mean years of education = 10.01, SD = 4.65; 67% female) underwent MRI of the brain and completed the HCHS Chronic Stress measure, a lifetime nicotine use question, and the WMS-III Logical Memory Delayed Recall subtest (LM-II). Two models evaluating HCHS Chronic Stress score and lifetime smoking behavior as moderators of the relation between hippocampal volume and LM-II were run. Results Moderation analyses revealed the endorsement of ever smoking cigarettes was a significant moderator for the relation between hippocampal volume and LM-II performance (Smoking: Estimate = −0.012, p = 0.005). Additionally, increased chronic stress was also a significant moderator for the relation between hippocampal volume and LM-II performance (Chronic Stress: Estimate = −0.001, p = 0.021). Conclusions The current findings suggest that smoking and chronic stress each acted as a moderator of the relation between hippocampal volume and memory, though the effects were small. Future research should examine whether there is a dose–response relationship for cigarette smoking and how this moderates brain health and memory. Additionally, whether there is an interactive effect between stress and smoking warrants further study.

Open-Source Throttling of CD8+ T Cells in Brain with Low-Intensity Focused Ultrasound-Guided Sequential Delivery of CXCL10, IL-2, and aPD-L1 for Glioblastoma Immunotherapy.

Improving clinical immunotherapy for glioblastoma (GBM) relies on addressing the immunosuppressive tumor microenvironment (TME). Enhancing CD8+ T cell infiltration and preventing its exhaustion holds promise for effective GBM immunotherapy. Here, a low-intensity focused ultrasound (LIFU)-guided sequential delivery strategy is developed to enhance CD8+ T cells infiltration and activity in the GBM region. The sequential delivery of CXC chemokine ligand 10 (CXCL10) to recruit CD8+ T cells and interleukin-2 (IL-2) to reduce their exhaustion is termed an "open-source throttling" strategy. Consequently, up to 3.39-fold of CD8+ T cells are observed with LIFU-guided sequential delivery of CXCL10, IL-2, and anti-programmed cell death 1 ligand 1 (aPD-L1), compared to the free aPD-L1 group. The immune checkpoint inhibitors (ICIs) therapeutic efficacy is substantially enhanced by the reversed immunosuppressive TME due to the expansion of CD8+ T cells, resulting in the elimination of tumor, prolonged survival time, and long-term immune memory establishment in orthotopic GBM mice. Overall, LIFU-guided sequential cytokine and ICIs delivery offers an "open-source throttling" strategy of CD8+ T cells, which may present a promising strategy for brain-tumor immunotherapy.

EXPRESS: Towards theoretically understanding how long-term memory semantics can support working memory performance.

Working memory is the system that supports the temporary storage and processing of information. It is generally agreed that working memory is a mental workspace, with a combination of resources operating together to maintain information in mind for potential use in thought and action. Theories typically acknowledge contributions of long-term memory to this system. One particular aspect of long-term memory, namely semantic long-term memory, can effectively supplement or 'boost' working memory performance. This may be a relatively automatic process via the semantic properties of the stimuli or more active via strategy development and implementation. However, the precise mechanisms require greater theoretical understanding. In this review of the literature, we critically discuss theoretical models of working memory and their proposed links with long-term memory. We also explore empirical research that contributes to our understanding of the ways in which semantics can support performance on both verbal and visuospatial working memory tasks, with a view to potential intervention development. This includes the possibility of training people with lower performance (e.g., older adults) to use semantics during working memory tasks. We conclude that semantics may offer an opportunity to maximise working memory performance. However, to realise this potential, more research is needed, particularly in the visuospatial domain.

The role of transposable elements in long-term memory formation

The role of transposable elements in long-term memory formation

I see artifacts: ICA-based EEG artifact removal does not improve deep network decoding across three BCI tasks

Abstract \textit{Objective.}
In this paper, we conduct a detailed investigation on the effect of IC-based noise rejection methods in neural network classifier-based decoding of electroencephalography (EEG) data in different task datasets.
\textit{Approach.}
We apply a pipeline matrix of two popular different Independent Component (IC) decomposition methods (Infomax, AMICA) with three different component rejection strategies (none, ICLabel, and MARA) on three different EEG datasets (Motor imagery, long-term memory formation, and visual memory). We cross-validate processed data from each pipeline with three architectures commonly used for EEG classification (two convolutional neural networks (CNN) and one long short term memory (LSTM) based model. We compare decoding performances on within-participant and within-dataset levels. 
\textit{Main Results.}
Our results show that the benefit from using IC-based noise rejection for decoding analyses is at best minor, as component-rejected data did not show consistently better performance than data without rejections---especially given the significant computational resources required for ICA computations.
\textit{Significance.}
With ever growing emphasis on transparency and reproducibility, as well as the obvious benefits arising from streamlined processing of large-scale datasets, there has been an increased interest in automated methods for pre-processing EEG data. One prominent part of such pre-processing pipelines consists of identifying and potentially removing artifacts arising from extraneous sources. This is typically done via Independent Component (IC) based correction for which numerous methods have been proposed, differing not only in the decomposition of the raw data into ICs, but also in how they reject the computed ICs. While the benefits of these methods are well established in univariate statistical analyses, it is unclear whether they help in multivariate scenarios, and specifically in neural network based decoding studies. As computational costs for pre-processing large-scale datasets are considerable, it is important to consider whether the tradeoff between model performance and available resources is worth the effort.

Structural brain preservation: a potential bridge to future medical technologies

When faced with the prospect of death, some people would prefer a form of long-term preservation that may allow them to be restored to healthy life in the future, if technology ever develops to the point that this is feasible and humane. Some believe that we may have the capacity to perform this type of experimental preservation today—although it has never been proven—using contemporary methods to preserve the structure of the brain. The idea is that the morphomolecular organization of the brain encodes the information required for psychological properties such as personality and long-term memories. If these structures in the brain can be maintained intact over time, this could theoretically provide a bridge to access restorative technologies in the future. To consider this hypothesis, we first describe possible metrics that can be used to assess structural brain preservation quality. We next explore several possible methods to preserve structural information in the brain, including the traditional cryonics method of cryopreservation, as well as aldehyde-stabilized cryopreservation and fluid preservation. We focus in-depth on fluid preservation, which relies on aldehyde fixation to induce chemical gel formation in a wide set of biomolecules and appears to be a cost-effective method. We describe two theoretical recovery technologies, alongside several of the ethical and legal complexities of brain preservation, all of which will require a prudent approach. We believe contemporary structural brain preservation methods have a non-negligible chance of allowing successful restoration in the future and that this deserves serious research efforts by the scientific community.