scholarly journals Identifying a task-invariant cognitive reserve network using task potency

2019 ◽  
Author(s):  
A.C. van Loenhoud ◽  
C. Habeck ◽  
W.M. van der Flier ◽  
R. Ossenkoppele ◽  
Y. Stern
Keyword(s):  
Functional Connectivity ◽  
Episodic Memory ◽  
Cortical Thickness ◽  
Cognitive Abilities ◽  
Latent Variable ◽  
Cognitive Reserve ◽  
Normal Sample ◽  
Neural Basis ◽  
Or Education ◽  
Fluid Reasoning

AbstractCognitive reserve (CR) is thought to protect against the consequence of age- or disease-related structural brain changes across multiple cognitive domains. The neural basis of CR may therefore comprise a functional network that is actively involved in many different cognitive processes. To investigate the existence of such a “task-invariant” CR network, we measured functional connectivity in a cognitively normal sample between 20-80 years old (N=265), both at rest and during the performance of 11 separate tasks that aim to capture four latent cognitive abilities (i.e. vocabulary, episodic memory, processing speed, and fluid reasoning). For each individual, we determined the change in functional connectivity from the resting state to each task state, which is referred to as “task potency” (Chauvin et al., 2017; Chauvin et al., 2018). Task potency was calculated for each pair among 264 nodes (Power et al., 2011) and then summarized across tasks reflecting the same cognitive ability. Subsequently, we established the correlation between task potency and premorbid IQ or education (i.e. CR factors). We identified a set of 57 pairs in which task potency showed significant correlations with IQ, but not education, across all four cognitive abilities. These pairs were included in a principal component analysis, from which we extracted the first component to obtain a latent variable reflecting task potency in this task-invariant CR network. This task potency variable moderated the relationship between cortical thickness and episodic memory performance (β=−.64, p=.01), and showed a direct effect on fluid reasoning (β=.08, p<.01) after adjusting for the effects of cortical thickness. Our identification of this task-invariant network contributes to a better understanding of the mechanism underlying CR, which may facilitate the development of CR-enhancing treatments. Our work also offers a useful alternative operational measure of CR future studies.

Comparison of Education and Episodic Memory as Modifiers of Brain Atrophy Effects on Cognitive Decline: Implications for Measuring Cognitive Reserve

2021 ◽  
pp. 1-11
Author(s):  
Dan Mungas ◽  
Evan Fletcher ◽  
Brandon E. Gavett ◽  
Keith Widaman ◽  
Laura B. Zahodne ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Cognitive Decline ◽  
Gray Matter ◽  
Cognitive Abilities ◽  
Cognitive Reserve ◽  
Cognitive Change ◽  
Interactive Effects ◽  
Neural Basis ◽  
Atrophy Rate ◽  
The Impact

Abstract Objective: This study compared the level of education and tests from multiple cognitive domains as proxies for cognitive reserve. Method: The participants were educationally, ethnically, and cognitively diverse older adults enrolled in a longitudinal aging study. We examined independent and interactive effects of education, baseline cognitive scores, and MRI measures of cortical gray matter change on longitudinal cognitive change. Results: Baseline episodic memory was related to cognitive decline independent of brain and demographic variables and moderated (weakened) the impact of gray matter change. Education moderated (strengthened) the gray matter change effect. Non-memory cognitive measures did not incrementally explain cognitive decline or moderate gray matter change effects. Conclusions: Episodic memory showed strong construct validity as a measure of cognitive reserve. Education effects on cognitive decline were dependent upon the rate of atrophy, indicating education effectively measures cognitive reserve only when atrophy rate is low. Results indicate that episodic memory has clinical utility as a predictor of future cognitive decline and better represents the neural basis of cognitive reserve than other cognitive abilities or static proxies like education.

scholarly journals Making Cognitive Latent Variables Manifest: Distinct Neural Networks for Fluid Reasoning and Processing Speed

2015 ◽  
Vol 27 (6) ◽  
pp. 1249-1258 ◽  
Author(s):  
Christian Habeck ◽  
Jason Steffener ◽  
Daniel Barulli ◽  
Yunglin Gazes ◽  
Qolamreza Razlighi ◽  
...  
Keyword(s):  
Individual Differences ◽  
Cognitive Ability ◽  
Cognitive Abilities ◽  
Latent Variables ◽  
Latent Variable ◽  
Cognitive Tasks ◽  
Neural Activation ◽  
Strongly Correlated ◽  
Activation Patterns ◽  
Fluid Reasoning

Cognitive psychologists posit several specific cognitive abilities that are measured with sets of cognitive tasks. Tasks that purportedly tap a specific underlying cognitive ability are strongly correlated with one another, whereas performances on tasks that tap different cognitive abilities are less strongly correlated. For these reasons, latent variables are often considered optimal for describing individual differences in cognitive abilities. Although latent variables cannot be directly observed, all cognitive tasks representing a specific latent ability should have a common neural underpinning. Here, we show that cognitive tasks representing one ability (i.e., either perceptual speed or fluid reasoning) had a neural activation pattern distinct from that of tasks in the other ability. One hundred six participants between the ages of 20 and 77 years were imaged in an fMRI scanner while performing six cognitive tasks, three representing each cognitive ability. Consistent with prior research, behavioral performance on these six tasks clustered into the two abilities based on their patterns of individual differences and tasks postulated to represent one ability showed higher similarity across individuals than tasks postulated to represent a different ability. This finding was extended in the current report to the spatial resemblance of the task-related activation patterns: The topographic similarity of the mean activation maps for tasks postulated to reflect the same reference ability was higher than for tasks postulated to reflect a different reference ability. Furthermore, for any task pairing, behavioral and topographic similarities of underlying activation patterns are strongly linked. These findings suggest that differences in the strengths of correlations between various cognitive tasks may be because of the degree of overlap in the neural structures that are active when the tasks are being performed. Thus, the latent variable postulated to account for correlations at a behavioral level may reflect topographic similarities in the neural activation across different brain regions.

scholarly journals IQ moderation of cognitive decline supports cognitive reserve and not brain maintenance

2021 ◽  
Author(s):  
Yunglin Gazes ◽  
Seonjoo Lee ◽  
Zhiqian Fang ◽  
Ashley Mensing ◽  
Diala Noofoory ◽  
...  
Keyword(s):  
Protective Effect ◽  
Cognitive Decline ◽  
Processing Speed ◽  
Cognitive Abilities ◽  
Cognitive Reserve ◽  
List Type ◽  
Cognitive Changes ◽  
Moderating Factors ◽  
Fluid Reasoning ◽  
Brain Maintenance

AbstractBackgroundWhile cognitive decline has been frequently reported in aging research, moderating factors for cognitive changes in healthy aging have been inconclusive. This study evaluated 5-year changes in four cognitive abilities and the potential moderation of age and cognitive reserve (CR) factors on cognitive changes.MethodsParticipants included 254 healthy adults initially aged 20 – 80 years. Six tasks estimated each of the four abilities: fluid reasoning, processing speed, memory and vocabulary. The proxies for CR included years of education and IQ. Cognitive changes and moderating factors were examine using multiple indicator latent change score model. Change point analysis pinpointed inflection points after which cognitive changes accelerated.ResultsThere was significant decline over five years in fluid reasoning, processing speed and memory, with age moderation such that older age was associated with steeper decline. Accelerated decline was observed earlier for reasoning and speed, at ages 58 and 59 years respectively, than for memory, at age 70 years. Vocabulary continued to improve until reaching peak performance at 67 years. For moderation of cognitive changes by CR proxies, while education did not show significant moderation, higher IQ was associated with reduced 5-year decline in reasoning and memory but not processing speed. CR moderation effect was found to be independent of mean cortical thickness.ConclusionsUsing a robust statistical model to estimate the latent change in four cognitive abilities over 5 years, the results showed that cognitive reserve rather than brain maintenance is the potential mechanism underlying IQ’s protective effect on cognitive decline.HighlightsReasoning and processing speed show accelerated decline after ages 59 and 58 years, respectively.Memory shows accelerated decline after age 70 years.Vocabulary performance peaks at age 67 years.Higher IQ is protective of cognitive decline in reasoning and memory but not for processing speed.IQ’s protective effect on cognition is independent of brain maintenance.

scholarly journals Assessment of cognitive reserve using near infrared spectroscopy

2018 ◽  
Author(s):  
Andrei V. Medvedev
Keyword(s):  
Prefrontal Cortex ◽  
Infrared Spectroscopy ◽  
Functional Connectivity ◽  
Near Infrared Spectroscopy ◽  
Cognitive Abilities ◽  
Cognitive Reserve ◽  
Near Infrared ◽  
Correlation Coefficients ◽  
Cost Effective ◽  
Optical Data

AbstractCognitive reserve (CR) is the ability to preserve cognitive functions in the presence of brain pathology. One commonly used proxy measure of CR is IQ. In the context of Alzheimer’s disease (AD), patients with higher CR show better cognitive performance relative to brain damage therefore higher CR reduces the risk of dementia. There is a strong need to develop a reliable biomarker of CR given the growing interest in understanding protective brain mechanisms in AD. Recent fMRI studies indicate that frontoparietal network may play an important role in the maintenance of cognitive reserve. The goal of this study was to measure functional connectivity (FC) of the prefrontal cortex using near infrared spectroscopy (NIRS) and to study the relationship of prefrontal FC with cognitive abilities and motoric skills.We analyzed resting state optical data recorded from prefrontal cortex in 13 healthy individuals who were also assessed by Wechsler Abbreviated Scale of Intelligence (WASI) test and the Purdue Pegboard test (PPT). For each participant, activity of each prefrontal channel was correlated with all other channels and positive correlation coefficients were Fisher-transformed and averaged over all PFC channels giving the Global Functional Connectivity (GFC) of PFC. The resulting GFC number for each individual was then correlated with the corresponding IQ (WASI full score) and the PPT scores.Prefrontal connectivity was found to positively correlate with IQ while showing the lack of or negative correlation with the Purdue Pegboard subtests. These results demonstrate that the cost-effective and noninvasive NIRS technology can be used to evaluate prefrontal functional connectivity thus providing a neurophysiological measure of cognitive reserve.E-mail address for correspondence:[email protected]

scholarly journals High resolution structural and functional MRI of the hippocampus in young adults with Down syndrome

2021 ◽  
Author(s):  
Katherine A Koenig ◽  
Se-Hong Oh ◽  
Melissa R Stasko ◽  
Elizabeth C Roth ◽  
H Gerry Taylor ◽  
...  
Keyword(s):  
Down Syndrome ◽  
Functional Connectivity ◽  
Cortical Thickness ◽  
Right Hemisphere ◽  
Gray Matter Volume ◽  
Drug Efficacy ◽  
Structure And Function ◽  
7 Tesla ◽  
Whole Brain ◽  
And Function

Abstract Down syndrome is the phenotypic consequence of trisomy 21, with clinical presentation including both neurodevelopmental and neurodegenerative components. Although the intellectual disability typically displayed by individuals with Down syndrome is generally global, it also involves disproportionate deficits in hippocampally-mediated cognitive processes. Hippocampal dysfunction may also relate to Alzheimer’s disease-type pathology, which can appear in as early as the first decade of life and becomes universal by age 40. Using 7-tesla MRI of the brain, we present an assessment of the structure and function of the hippocampus in 34 individuals with Down syndrome (mean age 24.5 years ± 6.5) and 27 age- and sex-matched typically developing healthy controls. In addition to increased whole-brain mean cortical thickness and lateral ventricle volumes (p &lt; 1.0 × 10−4), individuals with Down syndrome showed selective volume reductions in bilateral hippocampal subfields CA1, dentate gyrus, and tail (p &lt; 0.005). In the group with Down syndrome, bilateral hippocampi showed widespread reductions in the strength of functional connectivity, predominately to frontal regions (p &lt; 0.02). Age was not related to hippocampal volumes or functional connectivity measures in either group, but both groups showed similar relationships of age to whole-brain volume measures (p &lt; 0.05). Finally, we performed an exploratory analysis of a subgroup of individuals with Down syndrome with both imaging and neuropsychological assessments. This analysis indicated that measures of spatial memory were related to mean cortical thickness, total gray matter volume, and right hemisphere hippocampal subfield volumes (p &lt; 0.02). This work provides a first demonstration of the usefulness of high-field MRI to detect subtle differences in structure and function of the hippocampus in individuals with Down syndrome, and suggests the potential for development of MRI-derived measures as surrogate markers of drug efficacy in pharmacological studies designed to investigate enhancement of cognitive function.

scholarly journals Moderating Effect of Cognitive Reserve on Brain Integrity and Cognitive Performance

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 285-285
Author(s):  
Monica Nelson ◽  
Ross Andel ◽  
Julie Martinkova ◽  
Kateřina Čechová ◽  
Hana Marková ◽  
...  
Keyword(s):  
Cognitive Performance ◽  
Executive Control ◽  
Cognitive Reserve ◽  
Brain Aging ◽  
Treatment Options ◽  
Hippocampal Volume ◽  
Subjective Cognitive Decline ◽  
Or Education ◽  
Occupational Position ◽  
Using Data

Abstract Dementia is arguably the most devastating condition of older adulthood with treatment options still elusive. Alzheimer’s is the most prevalent form of dementia where cognitive deficits relate strongly to underlying brain pathology. However, there exist cases in which cognitive performance does not match the corresponding level of neuropathology. Attempts to explain this phenomenon often include the concept of cognitive reserve (CR), whereby greater CR (e.g., more education or higher occupational position) presumably results in less impairment relative to the extent of pathology early in disease progression but also greater impairment once cognitive symptoms manifest. We examined the influence of CR proxy variables (education and occupation) on the relationship between hippocampal volume and cognitive performance on tests of executive control and memory using data from the Czech Brain Aging Study (CBAS). Participants were cognitively normal/with subjective cognitive decline but without actual impairment (CN; n=115; M(age)=66.43; M(education)=15.90; 37 men) or had amnestic mild cognitive impairment (aMCI; n=165; M(age)=71.37; M(education)=14.92; 85 men). We found that hippocampal volume was significantly related to executive control (b=-.0001, p=.03) and memory (b=.0002, p&lt;.001) for participants with aMCI, but only memory (b=.0002, p=.03) for CN participants. Occupational position moderated the association between memory and hippocampal volume in aMCI, with the result approaching significance (p=.07), whereby a greater link between memory problems and hippocampal atrophy was present in those previously in high occupational positions. No other moderations for occupational position or education emerged (ps&gt;.25). We found evidence for the concept of CR using occupational position as proxy.

scholarly journals Working Memory, Fluid Reasoning, and Complex Problem Solving: Different Results Explained by the Brunswik Symmetry

2021 ◽  
Vol 9 (1) ◽  
pp. 5
Author(s):  
André Kretzschmar ◽  
Stephan Nebe
Keyword(s):  
Working Memory ◽  
Problem Solving ◽  
Cognitive Abilities ◽  
Latent Variables ◽  
Complex Problem ◽  
Equation Modeling ◽  
Complex Problem Solving ◽  
Symmetry Principle ◽  
Fluid Reasoning ◽  
The Impact

In order to investigate the nature of complex problem solving (CPS) within the nomological network of cognitive abilities, few studies have simultantiously considered working memory and intelligence, and results are inconsistent. The Brunswik symmetry principle was recently discussed as a possible explanation for the inconsistent findings because the operationalizations differed greatly between the studies. Following this assumption, 16 different combinations of operationalizations of working memory and fluid reasoning were examined in the present study (N = 152). Based on structural equation modeling with single-indicator latent variables (i.e., corrected for measurement error), it was found that working memory incrementally explained CPS variance above and beyond fluid reasoning in only 2 of 16 conditions. However, according to the Brunswik symmetry principle, both conditions can be interpreted as an asymmetrical (unfair) comparison, in which working memory was artificially favored over fluid reasoning. We conclude that there is little evidence that working memory plays a unique role in solving complex problems independent of fluid reasoning. Furthermore, the impact of the Brunswik symmetry principle was clearly demonstrated as the explained variance in CPS varied between 4 and 31%, depending on which operationalizations of working memory and fluid reasoning were considered. We argue that future studies investigating the interplay of cognitive abilities will benefit if the Brunswik principle is taken into account.

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