scholarly journals Independent Contributions of Dorsolateral Prefrontal Structure and Function to Working Memory in Healthy Older Adults

2020 ◽  
Author(s):  
Nicole D Evangelista ◽  
Andrew O’Shea ◽  
Jessica N Kraft ◽  
Hanna K Hausman ◽  
Emanuel M Boutzoukas ◽  
...  
Keyword(s):  
Older Adults ◽  
Working Memory ◽  
Surface Area ◽  
Structure And Function ◽  
Bold Signal ◽  
Healthy Older Adults ◽  
Left Dlpfc ◽  
Dorsolateral Prefrontal ◽  
Logistic Regressions ◽  
And Function

Abstract Age-related differences in dorsolateral prefrontal cortex (DLPFC) structure and function have each been linked to working memory. However, few studies have integrated multimodal imaging to simultaneously investigate relationships among structure, function, and cognition. We aimed to clarify how specifically DLPFC structure and function contribute to working memory in healthy older adults. In total, 138 participants aged 65–88 underwent 3 T neuroimaging and were divided into higher and lower groups based on a median split of in-scanner n-back task performance. Three a priori spherical DLPFC regions of interest (ROIs) were used to quantify blood-oxygen-level-dependent (BOLD) signal and FreeSurfer-derived surface area, cortical thickness, and white matter volume. Binary logistic regressions adjusting for age, sex, education, and scanner type revealed that greater left and right DLPFC BOLD signal predicted the probability of higher performing group membership (P values<.05). Binary logistic regressions also adjusting for total intracranial volume revealed left DLPFC surface area that significantly predicted the probability of being in the higher performing group (P = 0.017). The left DLPFC BOLD signal and surface area were not significantly associated and did not significantly interact to predict group membership (P values>.05). Importantly, this suggests BOLD signal and surface area may independently contribute to working memory performance in healthy older adults.

scholarly journals Free-Living Physical Activity Measured With a Wearable Device Is Associated With Larger Hippocampus Volume and Greater Functional Connectivity in Healthy Older Adults: An Observational, Cross-Sectional Study in Northern Portugal

2021 ◽  
Vol 13 ◽  
Author(s):  
Célia Domingos ◽  
Maria Picó-Pérez ◽  
Ricardo Magalhães ◽  
Mariana Moreira ◽  
Nuno Sousa ◽  
...  
Keyword(s):  
Physical Activity ◽  
Older Adults ◽  
Functional Connectivity ◽  
Brain Structure ◽  
Structure And Function ◽  
Community Dwelling ◽  
Cross Sectional ◽  
Healthy Older Adults ◽  
Brain Structure And Function ◽  
And Function

Several studies using neuroimaging techniques have established a positive relationship between physical activity (PA) and brain structure and function in older populations. However, the use of subjective measures of PA and the lack of multimodal neuroimaging approaches have limited the understanding of this association. This study aims to explore the associations between PA and brain structure and function by objectively evaluating PA. Community-dwelling cognitively healthy older adults (without diagnosed cognitive, neurological or degenerative disease) were recruited from local health centers and local gyms. In a cross-sectional design, participants were evaluated regarding cognitive, clinical, anthropometric, physical performance, and lifestyle characteristics. A 3 T magnetic resonance imaging (MRI) was performed for structural and functional brain measures. PA time and level was assessed via a Xiaomi Mi Band 2® worn for 15 consecutive days. Participants (n = 110, after inclusion/exclusion criteria and completion of all evaluations) were 58 females (56%), with an average age of 68.42 years old (SD = 3.12), most were active. Multiple regression analysis revealed that higher time spent in vigorous PA associated with larger left parahippocampal gyrus and right hippocampus volumes. Furthermore, the analysis of the functional connectome indicated a greater functional connectivity (FC) between the frontal gyrus, cingulate gyrus, occipital inferior lobe for light, moderate, and total PA time, and sedentary time associated with lower FC in the same networks. Overall, the structural and functional findings may provide evidence on the relevant association between PA and brain health in aging.

scholarly journals Sequence Variation Associated with SLC12A5 Gene Expression Is Linked to Brain Structure and Function in Healthy Adults

2019 ◽  
Vol 29 (11) ◽  
pp. 4654-4661 ◽  
Author(s):  
Michael D Gregory ◽  
J Shane Kippenhan ◽  
Joseph H Callicott ◽  
Daniel Y Rubinstein ◽  
Venkata S Mattay ◽  
...  
Keyword(s):  
Working Memory ◽  
Brain Structure ◽  
Gray Matter Volume ◽  
Memory Task ◽  
Structural Mri ◽  
Structure And Function ◽  
Mmp9 Expression ◽  
Dorsolateral Prefrontal ◽  
Brain Structure And Function ◽  
And Function

Abstract A single-nucleotide polymorphism in the promoter region of the Matrix Metalloproteinase-9 (MMP9) gene, rs3918242, has been shown to affect MMP9 expression in macrophages and was associated with schizophrenia by two independent groups. However, rs3918242's effects on MMP9 expression were not replicable in cell lines or brain tissue. Additionally, publically available data indicate that rs3918242 genotype is related not to MMP9 expression, but rather to expression of SLC12A5, a nearby gene coding for a K+/Cl- cotransporter, whose expression has also been related to schizophrenia. Here, we studied brain structure and function in healthy participants stratified by rs3918242 genotype using structural MRI (N = 298), functional MRI during an N-back working memory task (N = 554), and magnetoencephalography (MEG) during the same task (N = 190). We found rs3918242 was associated with gray matter volume (GMV) in the insula and dorsolateral prefrontal cortex bilaterally, closely replicated in discovery and replication samples; and with inferior parietal lobule (IPL) GMV when the samples were meta-analytically combined. Additionally, using both fMRI and MEG, rs3918242 was associated with right IPL working memory-related activation, replicated in two cohorts and across imaging modalities. These convergent results provide further impetus for examinations of the relationship of SLC12A5 with brain structure and function in neuropsychiatric disease.

scholarly journals No evidence for any effect of multiple sessions of frontal transcranial direct stimulation on mood in healthy older adults

2019 ◽  
Author(s):  
Malin Freidle ◽  
Jonna Nilsson ◽  
Alexander V. Lebedev ◽  
Martin Lövdén
Keyword(s):  
Older Adults ◽  
Working Memory ◽  
Emotional Regulation ◽  
Memory Task ◽  
Working Memory Training ◽  
Memory Training ◽  
Direct Stimulation ◽  
Healthy Older Adults ◽  
Dorsolateral Prefrontal ◽  
Clinical Populations

The dorsolateral prefrontal cortex (DLPFC) is part of a network important for emotional regulation and the possibility of modulating activity in this region with transcranial direct current stimulation (TDCS) to change mood has gained great interest, particularly for application in clinical populations. Whilst results in major depressive disorder have been promising, less is known about the effects of TDCS on mood in non-clinical populations. We hypothesized that multiple sessions of anodal TDCS applied over the left DLPFC would enhance mood, primarily as measured by the Profile of Mode States questionnaire, in healthy older adults. In addition, in an exploratory analysis, we examined the potentially moderating role of working memory training. Working memory, just like emotional regulation, taxes the DLPFC, which suggests that engaging in a working memory task whilst receiving TDCS may have a different effect on activity in this region and consequently mood. A total of 123 participants between 65 and 75 years of age were randomly assigned to receive either 20 sessions of TDCS, with or without working memory training, or 20 sessions sham stimulation, with or without working memory training. We found no support for enhancement of mood due to TDCS in healthy older adults, with or without cognitive training.

scholarly journals A Rubisco-binding protein is required for normal pyrenoid number and starch sheath morphology inChlamydomonas reinhardtii

2019 ◽  
Vol 116 (37) ◽  
pp. 18445-18454 ◽  
Author(s):  
Alan K. Itakura ◽  
Kher Xing Chan ◽  
Nicky Atkinson ◽  
Leif Pallesen ◽  
Lianyong Wang ◽  
...  
Keyword(s):  
Surface Area ◽  
Structure And Function ◽  
Binding Motif ◽  
Starch Granules ◽  
Wild Type ◽  
Bisphosphate Carboxylase ◽  
Biophysical Mechanism ◽  
Mechanism Function ◽  
And Function

A phase-separated, liquid-like organelle called the pyrenoid mediates CO2fixation in the chloroplasts of nearly all eukaryotic algae. While most algae have 1 pyrenoid per chloroplast, here we describe a mutant in the model algaChlamydomonasthat has on average 10 pyrenoids per chloroplast. Characterization of the mutant leads us to propose a model where multiple pyrenoids are favored by an increase in the surface area of the starch sheath that surrounds and binds to the liquid-like pyrenoid matrix. We find that the mutant’s phenotypes are due to disruption of a gene, which we call StArch Granules Abnormal 1 (SAGA1) because starch sheath granules, or plates, in mutants lacking SAGA1 are more elongated and thinner than those of wild type. SAGA1 contains a starch binding motif, suggesting that it may directly regulate starch sheath morphology. SAGA1 localizes to multiple puncta and streaks in the pyrenoid and physically interacts with the small and large subunits of the carbon-fixing enzyme Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase), a major component of the liquid-like pyrenoid matrix. Our findings suggest a biophysical mechanism by which starch sheath morphology affects pyrenoid number and CO2-concentrating mechanism function, advancing our understanding of the structure and function of this biogeochemically important organelle. More broadly, we propose that the number of phase-separated organelles can be regulated by imposing constraints on their surface area.

scholarly journals Cognitive Aftereffects of Acute tDCS Coupled with Cognitive Training: An fMRI Study in Healthy Seniors

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
P. Šimko ◽  
M. Pupíková ◽  
M. Gajdoš ◽  
I. Rektorová
Keyword(s):  
Older Adults ◽  
Working Memory ◽  
Cognitive Training ◽  
Brain Network ◽  
Resting State Functional Connectivity ◽  
Double Blind ◽  
Sham Stimulation ◽  
Highly Educated ◽  
Fmri Study ◽  
Dorsolateral Prefrontal

Enhancing cognitive functions through noninvasive brain stimulation is of enormous public interest, particularly for the aging population in whom processes such as working memory are known to decline. In a randomized double-blind crossover study, we investigated the acute behavioral and neural aftereffects of bifrontal and frontoparietal transcranial direct current stimulation (tDCS) combined with visual working memory (VWM) training on 25 highly educated older adults. Resting-state functional connectivity (rs-FC) analysis was performed prior to and after each stimulation session with a focus on the frontoparietal control network (FPCN). The bifrontal montage with anode over the left dorsolateral prefrontal cortex enhanced VWM accuracy as compared to the sham stimulation. With the rs-FC within the FPCN, we observed significant stimulation × time interaction using bifrontal tDCS. We found no cognitive aftereffects of the frontoparietal tDCS compared to sham stimulation. Our study shows that a single bifrontal tDCS combined with cognitive training may enhance VWM performance and rs-FC within the relevant brain network even in highly educated older adults.

Replacing surface-area to volume with diffusion length

2021 ◽  
Author(s):  
Tzachi Bar
Keyword(s):  
Surface Area ◽  
Diffusion Length ◽  
Structure And Function ◽  
Fast Diffusion ◽  
Mathematical Framework ◽  
Simple Explanation ◽  
Academic Degree ◽  
Visual Spatial ◽  
And Function ◽  
Graphical Illustration

Surface-area to volume (S/V) has central place in STEM syllabuses, explaining the relation between structure and function governed by the heat equation, such as in diffusion and heat transfer by conduction. However, teaching the abstract S/V quotient faces many difficulties, due to the need for high reasoning abilities and visual-spatial skills. Surprisingly, an exploratory survey among 64 high school biology teachers revealed that 12.5% of them teach the relation between structure and function in diffusion by one dimensional, tangible, quotient free, explanation: small and non-spherical structure results in short diffusion length, which results in fast diffusion. Those teachers tend to hold higher academic degree (p= 0.002) and be more experienced (p=0.045). A plausible explanation for the limited usage in the 'diffusion length' model may be the lack of mathematical framework and graphical illustration to support it. Here I link the diffusion length, volume (V) and surface-area (S) and show that the average diffusion length = 3V/S and present an illustration of V/S. Therefore, the small, non-spherical shapes of structures adopted for fast diffusion can be equivalently explained by the short diffusion length in these structures. Having the necessary mathematical framework and graphical illustration should help other teachers adopt this simple explanation.

Pharmacology and Drug Therapy in Critically Ill Elderly Patients

1992 ◽  
Vol 3 (1) ◽  
pp. 137-148 ◽  
Author(s):  
Mary K. Walker
Keyword(s):  
Older Adults ◽  
Critical Care ◽  
Drug Therapy ◽  
Drug Metabolism ◽  
Elderly Patients ◽  
Treatment Modality ◽  
Drug Disposition ◽  
Structure And Function ◽  
Living Things ◽  
And Function

Aging is a complex, normal, and inevitable process affecting all living things. The physiologic changes of aging, by definition, are postmaturational, occurring after adult maturity is achieved. Changes with aging are primary, irreversible, and progressive. While the processes of aging are neither pathology nor disease, they present important changes in structure and function that alter drug disposition, metabolic rate, and excretion. These changes present special challenges to clinicians in critical care settings for whom pharmacotherapy is a common treatment modality. This article explores the physiologic changes associated with aging and the implications of these changes for management of critically compromised elders. Drug metabolism, distribution, utilization, and excretion in older adults are examined

scholarly journals Reviewing working memory training gains in healthy older adults: A meta-analytic review of transfer for cognitive outcomes

2019 ◽  
Vol 103 ◽  
pp. 163-177 ◽  
Author(s):  
Ana C. Teixeira-Santos ◽  
Célia S. Moreira ◽  
Rosana Magalhães ◽  
Carina Magalhães ◽  
Diana R. Pereira ◽  
...  
Keyword(s):  
Older Adults ◽  
Working Memory ◽  
Cognitive Outcomes ◽  
Working Memory Training ◽  
Memory Training ◽  
Healthy Older Adults ◽  
Analytic Review

scholarly journals The Long-Term Efficacy of Working Memory Training in Healthy Older Adults: A Systematic Review and Meta-Analysis of 22 Randomized Controlled Trials

2020 ◽  
Vol 75 (8) ◽  
pp. e174-e188
Author(s):  
Jianhua Hou ◽  
Taiyi Jiang ◽  
Jiangning Fu ◽  
Bin Su ◽  
Hao Wu ◽  
...  
Keyword(s):  
Older Adults ◽  
Working Memory ◽  
Meta Analysis ◽  
Cochrane Library ◽  
Memory Training ◽  
Long Term Effects ◽  
Healthy Older Adults ◽  
Randomized Controlled ◽  
Randomized Controlled Studies

Abstract Objectives The long-lasting efficacy of working memory (WM) training has been a controversial and still ardently debated issue. In this meta-analysis, the authors explored the long-term effects of WM training in healthy older adults on WM subdomains and abilities outside the WM domain assessed in randomized controlled studies. Method A systematic literature search of PubMed, Web of Science, PsycINFO, Cochrane Library, ProQuest, clinicaltrials.gov, and Google Scholar was conducted. Random-effects models were used to quantitatively synthesize the existing data. Results Twenty-two eligible studies were included in the meta-analysis. The mean participant age ranged from 63.77 to 80.1 years. The meta-synthesized long-term effects on updating were 0.45 (95% confidence interval = 0.253–0.648, <6 months: 0.395, 0.171–0.619, ≥6 months: 0.641, 0.223–1.058), on shifting, 0.447 (0.246–0.648, <6 months: 0.448, 0.146–0.75, ≥6 months: 0.446, 0.176–0.716); on inhibition, 0.387 (0.228–0.547, <6 months: 0.248, 0.013–0.484, ≥6 months: 0.504, 0.288–0.712); on maintenance, 0.486 (0.352–0.62, <6 months: 0.52, 0.279–0.761, ≥6 months: 0.471, 0.31–0.63). Discussion The results showed that WM training exerted robust long-term effects on enhancing the WM system and improving processing speed and reasoning in late adulthood. Future studies are needed to use different tasks of the same WM construct to evaluate the WM training benefits, to adopt more ecological tasks or tasks related to daily life, to improve the external validity of WM training, and to identify the optimal implementation strategy for WM training.

Sign in / Sign up

Export Citation Format

Share Document