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PloS One 2024Semantic memory representations are generally well maintained in aging, whereas semantic control is thought to be more affected. To explain this phenomenon, this study...
Semantic memory representations are generally well maintained in aging, whereas semantic control is thought to be more affected. To explain this phenomenon, this study tested the predictions of the Compensation-Related Utilization of Neural Circuits Hypothesis (CRUNCH), focusing on task demands in aging as a possible framework. The CRUNCH effect would manifest itself in semantic tasks through a compensatory increase in neural activation in semantic control network regions but only up to a certain threshold of task demands. This study compares 39 younger (20-35 years old) with 39 older participants (60-75 years old) in a triad-based semantic judgment task performed in an fMRI scanner while manipulating task demand levels (low versus high) through semantic distance. In line with the CRUNCH predictions, differences in neurofunctional activation and behavioral performance (accuracy and response times) were expected in younger versus older participants in the low- versus high-demand conditions, which should be manifested in semantic control Regions of Interest (ROIs). Our older participants had intact behavioral performance, as proposed in the literature for semantic memory tasks (maintained accuracy and slower response times (RTs)). Age-invariant behavioral performance in the older group compared to the younger one is necessary to test the CRUNCH predictions. The older adults were also characterized by high cognitive reserve, as our neuropsychological tests showed. Our behavioral results confirmed that our task successfully manipulated task demands: error rates, RTs and perceived difficulty increased with increasing task demands in both age groups. We did not find an interaction between age group and task demand, or a statistically significant difference in activation between the low- and high-demand conditions for either RTs or accuracy. As for brain activation, we did not find the expected age group by task demand interaction, or a significant main effect of task demand. Overall, our results are compatible with some neural activation in the semantic network and the semantic control network, largely in frontotemporoparietal regions. ROI analyses demonstrated significant effects (but no interactions) of task demand in the left and right inferior frontal gyrus, the left posterior middle temporal gyrus, the posterior inferior temporal gyrus and the prefrontal gyrus. Overall, our test did not confirm the CRUNCH predictions.
Topics: Humans; Magnetic Resonance Imaging; Adult; Middle Aged; Aged; Male; Female; Semantics; Aging; Memory; Young Adult; Reaction Time; Brain Mapping; Nerve Net; Brain; Pre-Registration Publication
PubMed: 38917084
DOI: 10.1371/journal.pone.0289384 -
Neuropsychologia Jun 2024Research has documented changes in autobiographical memory and episodic future thinking in mild cognitive impairment (MCI) and Alzheimer's disease (AD). However,...
Research has documented changes in autobiographical memory and episodic future thinking in mild cognitive impairment (MCI) and Alzheimer's disease (AD). However, cognitive decline occurs gradually and recent findings suggest that subtle alterations in autobiographical cognition may be evident earlier in the trajectory towards dementia, before AD-related symptoms emerge or a clinical diagnosis has been given. The current study used the Autobiographical Interview to examine the episodic and semantic content of autobiographical past and future events generated by older adults (N = 38) of varying cognitive functioning who were grouped into High (N = 20) and Low Cognition (N = 18) groups based on their Montreal Cognitive Assessment (MoCA) scores. Participants described 12 past and 12 future autobiographical events, and transcripts were scored to quantify the numbers of internal (episodic) or external (non-episodic, including semantic) details. Although the Low Cognition group exhibited a differential reduction for internal details comprising both past and future events, they did not show the expected overproduction of external details relative to the High Cognition group. Multilevel modelling demonstrated that on trials lower in episodic content, semantic content was significantly increased in both groups. Although suggestive of a compensatory mechanism, the magnitude of this inverse relationship did not differ across groups or interact with MoCA scores. This finding indicates that external detail production may be underpinned by mechanisms not affected by cognitive decline, such as narrative style and the ability to contextualize one's past and future events in relation to broader autobiographical knowledge.
PubMed: 38908476
DOI: 10.1016/j.neuropsychologia.2024.108943 -
Computers in Biology and Medicine Jun 2024Differential expression (DE) analysis between cell types for scRNA-seq data by capturing its complicated features is crucial. Recently, different methods have been...
Differential expression (DE) analysis between cell types for scRNA-seq data by capturing its complicated features is crucial. Recently, different methods have been developed for targeting the scRNA-seq data analysis based on different modeling frameworks, assumptions, strategies and test statistic in considering various data features. The scDEA is an ensemble learning-based DE analysis method developed recently, yielding p-values using Lancaster's combination, generated by 12 individual DE analysis methods, and producing more accurate and stable results than individual methods. The objective of our study is to propose a new ensemble learning-based DE analysis method, scHD4E, using top performers in only 4 separate methods. The top performer 4 methods have been selected through an evaluation process using six real scRNA-seq data sets. We conducted comprehensive experiments for five experimental data sets to evaluate our proposed method based on the sample size effects, batch effects, type I error control, gene ontology enrichment analysis, runtime, identified matched DE genes, and semantic similarity measurement between methods. We also perform similar analyses (except the last 3 terms) and compute performance measures like accuracy, F1 score, Mathew's correlation coefficient etc. for a simulated data set. The results show that scHD4E is performs better than all the individual and scDEA methods in all the above perspectives. We expect that scHD4E will serve the modern data scientists for detecting the DEGs in scRNA-seq data analysis. To implement our proposed method, a Github R package scHD4E and its shiny application has been developed, and available in the following links: https://github.com/bbiswas1989/scHD4E and https://github.com/bbiswas1989/scHD4E-Shiny.
PubMed: 38897145
DOI: 10.1016/j.compbiomed.2024.108769 -
Frontiers in Plant Science 2024Canopy temperature (CT) is often interpreted as representing leaf activity traits such as photosynthetic rates, gas exchange rates, or stomatal conductance. This...
Canopy temperature (CT) is often interpreted as representing leaf activity traits such as photosynthetic rates, gas exchange rates, or stomatal conductance. This interpretation is based on the observation that leaf activity traits correlate with transpiration which affects leaf temperature. Accordingly, CT measurements may provide a basis for high throughput assessments of the productivity of wheat canopies during early grain filling, which would allow distinguishing functional from dysfunctional stay-green. However, whereas the usefulness of CT as a fast surrogate measure of sustained vigor under soil drying is well established, its potential to quantify leaf activity traits under high-yielding conditions is less clear. To better understand sensitivity limits of CT measurements under high yielding conditions, we generated within-genotype variability in stay-green functionality by means of differential short-term pre-anthesis canopy shading that modified the sink:source balance. We quantified the effects of these modifications on stay-green properties through a combination of gold standard physiological measurements of leaf activity and newly developed methods for organ-level senescence monitoring based on timeseries of high-resolution imagery and deep-learning-based semantic image segmentation. In parallel, we monitored CT by means of a pole-mounted thermal camera that delivered continuous, ultra-high temporal resolution CT data. Our results show that differences in stay-green functionality translate into measurable differences in CT in the absence of major confounding factors. Differences amounted to approximately 0.8°C and 1.5°C for a very high-yielding source-limited genotype, and a medium-yielding sink-limited genotype, respectively. The gradual nature of the effects of shading on CT during the stay-green phase underscore the importance of a high measurement frequency and a time-integrated analysis of CT, whilst modest effect sizes confirm the importance of restricting screenings to a limited range of morphological and phenological diversity.
PubMed: 38895615
DOI: 10.3389/fpls.2024.1335037 -
Sensors (Basel, Switzerland) Jun 2024Environmental mapping and robot navigation are the basis for realizing robot automation in modern agricultural production. This study proposes a new autonomous mapping...
Environmental mapping and robot navigation are the basis for realizing robot automation in modern agricultural production. This study proposes a new autonomous mapping and navigation method for gardening scene robots. First, a new LiDAR slam-based semantic mapping algorithm is proposed to enable the robots to analyze structural information from point cloud images and generate roadmaps from them. Secondly, a general robot navigation framework is proposed to enable the robot to generate the shortest global path according to the road map, and consider the local terrain information to find the optimal local path to achieve safe and efficient trajectory tracking; this method is equipped in apple orchards. The LiDAR was evaluated on a differential drive robotic platform. Experimental results show that this method can effectively process orchard environmental information. Compared with vnf and pointnet++, the semantic information extraction efficiency and time are greatly improved. The map feature extraction time can be reduced to 0.1681 s, and its MIoU is 0.812. The resulting global path planning achieved a 100% success rate, with an average run time of 4ms. At the same time, the local path planning algorithm can effectively generate safe and smooth trajectories to execute the global path, with an average running time of 36 ms.
PubMed: 38894456
DOI: 10.3390/s24113663 -
Journal of Clinical Medicine May 2024: The subject of this article is the reflection on hope-one of the most important predictors and motivators of human actions. Hope is our response to a threat, and it is...
: The subject of this article is the reflection on hope-one of the most important predictors and motivators of human actions. Hope is our response to a threat, and it is also the emotion that allows us to overcome hopelessness and to reduce suffering. Hoping is a human capacity with varying cognitive, emotional, and functional dimensions. Psychological, pedagogical (particularly in the framework of special-needs pedagogy and thanatological pedagogy), and theological reflection on hope can be helpful for dying people. The objective of this study was to characterize hope in the semantic space of individuals in the terminal stage of cancer and to verify whether age is a variable that determines this hope. : To complete the study, the Osgood semantic differential method was applied, as modified by Polish psychologist Dr. Boguslaw Block (the DSN-3 test). The research technique consisted of a therapeutic conversation. : Research results show that, in general, those in the terminal stage have positive associations with hope. In all three aspects of the used test, namely the cognitive, emotional, and functional aspects, the highest scores assigned to the perception of hope were obtained from men up to 35 years of age. Depending on the ages of patients, one could observe certain semantic shifts, but they did not prove to be statistically significant. : Polish males surveyed at the end of life due to cancer generally perceived hope as a supportive force. Therefore, hope can provide emotional support to patients in the terminal stage of cancer and improve their quality of life.
PubMed: 38892872
DOI: 10.3390/jcm13113162 -
Ecology and Evolution Jun 2024During past glacial periods, the land cover of Northern Eurasia and North America repeatedly shifted between open steppe tundra and boreal/temperate forest. Tracking...
During past glacial periods, the land cover of Northern Eurasia and North America repeatedly shifted between open steppe tundra and boreal/temperate forest. Tracking these changes and estimating the coverage of open versus forested vegetation in past glacial and interglacial landscapes is notoriously difficult because the characteristic dwarf birches of the tundra and the tree birches of the boreal and temperate forests produce similar pollen grains that are difficult to distinguish in the pollen record. One objective approach to separating dwarf birch pollen from tree birch pollen is to use grain size statistics. However, the required grain size measurements are time-consuming and, therefore, rarely produced. Here, we present an approach to automatic size measurement based on image recognition with convolutional neural networks and machine learning. It includes three main steps. First, the TOFSI algorithm is applied to detect and classify pollen, including birch pollen, in lake sediment samples. Second, a Resnet-18 neural network is applied to select the birch pollen suitable for measurement. Third, semantic segmentation is applied to detect the outline and the area and mean width of each detected birch pollen grain. Test applications with two pollen records from Northern Germany, one covering the Lateglacial-Early Holocene transition and the other covering the Mid to Late Pleistocene transition, show that the new technical approach is well suited to measure the area and mean width of birch pollen rapidly (>1000 per hour) and with high accuracy. Our new network-based tool facilitates more regular size measurements of birch pollen. Expanded analysis of modern birch pollen will help to better understand size variations in birch pollen between birch species and in response to environmental factors as well as differential sample preparation. Analysis of fossil samples will allow better quantification of dwarf birch versus tree birch in past environments.
PubMed: 38882530
DOI: 10.1002/ece3.11510 -
Ageing Research Reviews Jun 2024Semantic dementia is a kind of neurodegenerative disorder, characterized by prominent semantic impairments and anterior temporal lobe atrophy. Since 2010, more studies... (Review)
Review
Semantic dementia is a kind of neurodegenerative disorder, characterized by prominent semantic impairments and anterior temporal lobe atrophy. Since 2010, more studies have devoted to this rare disorder, revealing that it is more complex than we think. Clinical advances include more specific findings of semantic impairments and other higher order cognitive deficits. Neuroimaging techniques can help revealing the different brain networks affected (both structurally and functionally) in this condition. Pathological and genetic studies have also found more complex situations of semantic dementia, which might explain the huge variance existing in semantic dementia. Moreover, the current diagnosis criteria mainly focus on semantic dementia's classical prototype. We further delineated the features of three subtypes of semantic dementia based on atrophy lateralization with three severity stages. In a broader background, as a part of the continuum of neurodegenerative disorders, semantic dementia is commonly compared with other resembling conditions. Therefore, we summarized the differential diagnosis between semantic dementia and them. Finally, we introduced the challenges and achievements of its diagnosis, treatment, care and cross cultural comparison. By providing a comprehensive picture of semantic dementia on different aspects of advances, we hope to deepen the understanding of semantic dementia and promote more inspirations on both clinical and theoretical studies about it.
PubMed: 38866186
DOI: 10.1016/j.arr.2024.102375 -
Alzheimer's & Dementia : the Journal of... Jun 2024Frontotemporal lobar degeneration (FTLD) encompasses behavioral variant frontotemporal dementia (bvFTD), progressive supranuclear palsy, corticobasal...
INTRODUCTION
Frontotemporal lobar degeneration (FTLD) encompasses behavioral variant frontotemporal dementia (bvFTD), progressive supranuclear palsy, corticobasal syndrome/degeneration, and primary progressive aphasias (PPAs). We cross-validated fluid biomarkers and neuroimaging.
METHODS
Seven fluid biomarkers from cerebrospinal fluid and serum were related to atrophy in 428 participants including these FTLD subtypes, logopenic variant PPA (lvPPA), Alzheimer's disease (AD), and healthy subjects. Atrophy was assessed by structural magnetic resonance imaging and atlas-based volumetry.
RESULTS
FTLD subtypes, lvPPA, and AD showed specific profiles for neurofilament light chain, phosphorylated heavy chain, tau, phospho-tau, amyloid beta from serum/cerebrospinal fluid, and brain atrophy. Neurofilaments related to regional atrophy in bvFTD, whereas progranulin was associated with atrophy in semantic variant PPA. Ubiquitin showed no effects.
DISCUSSION
Results specify biomarker and atrophy patterns in FTLD and AD supporting differential diagnosis. They identify neurofilaments and progranulin in interaction with structural imaging as promising candidates for monitoring disease progression and therapy.
HIGHLIGHTS
Study cross-validated neuroimaging and fluid biomarkers in dementia. Five kinds of frontotemporal lobar degeneration and two variants of Alzheimer's disease. Study identifies disease-specific fluid biomarker and atrophy profiles. Fluid biomarkers and atrophy interact in a disease-specific way. Neurofilaments and progranulin are proposed as biomarkers for diagnosis and therapy.
PubMed: 38865340
DOI: 10.1002/alz.13863 -
PsyCh Journal Jun 2024In today's fast-paced society, escalating work and academic pressures have led to rising stress levels. While numerous studies have explored adolescent mental health,...
In today's fast-paced society, escalating work and academic pressures have led to rising stress levels. While numerous studies have explored adolescent mental health, there has been a lack of focus on "educational stress" among Chinese students. This study sought to understand the psychological and physiological effects of educational stress in Chinese university students. We studied the impact of a 5-min nature photography session on campus compared with a control activity of photographing urban settings near campus. Data were collected using blood pressure measurements, electroencephalography (EEG), the Semantic Differential Method (SDM), and the State-Trait Anxiety Inventory (STAI) in order to understand psychophysiological reactions. The findings from the SDM and STAI assessments indicated that students felt slightly more at ease and considerably more relaxed, had a heightened sense of naturalness, and experienced reduced anxiety after engaging in nature photography compared with urban photography. Notably, we observed that both systolic and diastolic blood pressure dropped by many values and there were noticeable EEG changes among participants. The results suggest that a brief 5-min nature photography activity can effectively reduce mental stress in Chinese university students.
PubMed: 38860783
DOI: 10.1002/pchj.773