scholarly journals Cerebellar and Prefrontal-Cortical Engagement During Higher-Order Rule Learning in Older Adulthood

2020 ◽  
Author(s):  
T. Bryan Jackson ◽  
Ted Maldonado ◽  
Sydney M. Eakin ◽  
Joseph M. Orr ◽  
Jessica A. Bernard

ABSTRACTTo date most aging research has focused on cortical systems and networks, ignoring the cerebellum which has been implicated in both cognitive and motor function. Critically, older adults (OA) show marked differences in cerebellar volume and functional networks, suggesting it may play a key role in the behavioral differences observed in advanced age. OA may be less able to recruit cerebellar resources due to network and structural differences. Here, 26 young adults (YA) and 25 OA performed a second-order learning task, known to activate the cerebellum in the fMRI environment. Behavioral results indicated that YA performed significantly better and learned more quickly compared to OA. Functional imaging detailed robust parietal and cerebellar activity during learning (compared to control) blocks within each group. OA showed increased activity (relative to YA) in the left inferior parietal lobe in response to instruction cues during learning (compared to control); whereas, YA showed increased activity (relative to OA) in the left anterior cingulate to feedback cues during learning, potentially explaining age-related performance differences. Visual interpretation of effect size maps showed more bilateral posterior cerebellar activation in OA compared to YA during learning blocks, but early learning showed widespread cerebellar activation in YA compared to OA. There were qualitatively large age-related differences in cerebellar recruitment in terms of effect sizes, yet no statistical difference. These findings serve to further elucidate age-related differences and similarities in cerebellar and cortical brain function and implicate the cerebellum and its networks as regions of interest in aging research.

2019 ◽  
Author(s):  
J Orpella ◽  
P Ripollés ◽  
M Ruzzoli ◽  
JL Amengual ◽  
A Callejas ◽  
...  

AbstractA crucial aspect when learning a language is discovering the rules that govern how words are combined in order to convey meanings. Since rules are characterized by sequential co-occurrences between elements (e.g. ‘These cupcakes are unbelievable’), tracking the statistical relationships between these elements is fundamental. However, statistical learning alone cannot fully account for the ability to create abstract rule representations that can be generalized, a paramount requirement of linguistic rules. Here, we provide evidence that, after the statistical relations between words have been extracted, the engagement of goal-directed attention is key to enable rule generalization. Incidental learning performance during a rule-learning task on an artificial language revealed a progressive shift from statistical learning to goal-directed attention. In addition, and consistent with the recruitment of attention, fMRI analyses of late learning stages showed left parietal activity within a broad bilateral dorsal fronto-parietal network. Critically, rTMS on participants’ peak of activation within the left parietal cortex impaired their ability to generalize learned rules to a structurally analogous new language. No stimulation or rTMS on a non-relevant brain region did not have the same interfering effect on generalization. Performance on an additional attentional task showed that rTMS on the same parietal site hindered participants’ ability to integrate what (stimulus identity) and when (stimulus timing) information about an expected target. The present findings suggest that learning rules from speech is a two-stage process: following statistical learning, goal-directed attention –involving left parietal regions– integrates what and when stimulus information to facilitate rapid rule generalization.


PLoS Biology ◽  
2020 ◽  
Vol 18 (11) ◽  
pp. e3000895
Author(s):  
Joan Orpella ◽  
Pablo Ripollés ◽  
Manuela Ruzzoli ◽  
Julià L. Amengual ◽  
Alicia Callejas ◽  
...  

A crucial aspect when learning a language is discovering the rules that govern how words are combined in order to convey meanings. Because rules are characterized by sequential co-occurrences between elements (e.g., “These cupcakes are unbelievable”), tracking the statistical relationships between these elements is fundamental. However, purely bottom-up statistical learning alone cannot fully account for the ability to create abstract rule representations that can be generalized, a paramount requirement of linguistic rules. Here, we provide evidence that, after the statistical relations between words have been extracted, the engagement of goal-directed attention is key to enable rule generalization. Incidental learning performance during a rule-learning task on an artificial language revealed a progressive shift from statistical learning to goal-directed attention. In addition, and consistent with the recruitment of attention, functional MRI (fMRI) analyses of late learning stages showed left parietal activity within a broad bilateral dorsal frontoparietal network. Critically, repetitive transcranial magnetic stimulation (rTMS) on participants’ peak of activation within the left parietal cortex impaired their ability to generalize learned rules to a structurally analogous new language. No stimulation or rTMS on a nonrelevant brain region did not have the same interfering effect on generalization. Performance on an additional attentional task showed that this rTMS on the parietal site hindered participants’ ability to integrate “what” (stimulus identity) and “when” (stimulus timing) information about an expected target. The present findings suggest that learning rules from speech is a two-stage process: following statistical learning, goal-directed attention—involving left parietal regions—integrates “what” and “when” stimulus information to facilitate rapid rule generalization.


2020 ◽  
Vol 48 (7) ◽  
pp. 1-19
Author(s):  
Ryan T. Daley ◽  
Holly J. Bowen ◽  
Eric C. Fields ◽  
Angela Gutchess ◽  
Elizabeth A. Kensinger

Self-relevance effects are often confounded by the presence of emotional content, rendering it difficult to determine how brain networks functionally connected to the ventromedial prefrontal cortex (vmPFC) are affected by the independent contributions of self-relevance and emotion. This difficulty is complicated by age-related changes in functional connectivity between the vmPFC and other default mode network regions, and regions typically associated with externally oriented networks. We asked groups of younger and older adults to imagine placing emotional and neutral objects in their home or a stranger's home. An age-invariant vmPFC cluster showed increased activation for self-relevant and emotional content processing. Functional connectivity analyses revealed age × self-relevance interactions in vmPFC connectivity with the anterior cingulate cortex. There were also age × emotion interactions in vmPFC functional connectivity with the anterior insula, orbitofrontal gyrus, inferior frontal gyrus, and supramarginal gyrus. Interactions occurred in regions with the greatest differences between the age groups, as revealed by conjunction analyses. Implications of the findings are discussed.


2019 ◽  
Vol 30 (1) ◽  
pp. 85-99 ◽  
Author(s):  
Farshad A Mansouri ◽  
Mark J Buckley ◽  
Daniel J Fehring ◽  
Keiji Tanaka

Abstract Imaging and neural activity recording studies have shown activation in the primate prefrontal cortex when shifting attention between visual dimensions is necessary to achieve goals. A fundamental unanswered question is whether representations of these dimensions emerge from top-down attentional processes mediated by prefrontal regions or from bottom-up processes within visual cortical regions. We hypothesized a causative link between prefrontal cortical regions and dimension-based behavior. In large cohorts of humans and macaque monkeys, performing the same attention shifting task, we found that both species successfully shifted between visual dimensions, but both species also showed a significant behavioral advantage/bias to a particular dimension; however, these biases were in opposite directions in humans (bias to color) versus monkeys (bias to shape). Monkeys’ bias remained after selective bilateral lesions within the anterior cingulate cortex (ACC), frontopolar cortex, dorsolateral prefrontal cortex (DLPFC), orbitofrontal cortex (OFC), or superior, lateral prefrontal cortex. However, lesions within certain regions (ACC, DLPFC, or OFC) impaired monkeys’ ability to shift between these dimensions. We conclude that goal-directed processing of a particular dimension for the executive control of behavior depends on the integrity of prefrontal cortex; however, representation of competing dimensions and bias toward them does not depend on top-down prefrontal-mediated processes.


Gerontology ◽  
2016 ◽  
Vol 63 (2) ◽  
pp. 103-117 ◽  
Author(s):  
Cia-Hin Lau ◽  
Yousin Suh

The recent advent of genome and epigenome editing technologies has provided a new paradigm in which the landscape of the human genome and epigenome can be precisely manipulated in their native context. Genome and epigenome editing technologies can be applied to many aspects of aging research and offer the potential to develop novel therapeutics against age-related diseases. Here, we discuss the latest technological advances in the CRISPR-based genome and epigenome editing toolbox, and provide insight into how these synthetic biology tools could facilitate aging research by establishing in vitro cell and in vivo animal models to dissect genetic and epigenetic mechanisms underlying aging and age-related diseases. We discuss recent developments in the field with the aims to precisely modulate gene expression and dynamic epigenetic landscapes in a spatial and temporal manner in cellular and animal models, by complementing the CRISPR-based editing capability with conditional genetic manipulation tools including chemically inducible expression systems, optogenetics, logic gate genetic circuits, tissue-specific promoters, and the serotype-specific adeno-associated virus. We also discuss how the combined use of genome and epigenome editing tools permits investigators to uncover novel molecular pathways involved in the pathophysiology and etiology conferred by risk variants associated with aging and aging-related disease. A better understanding of the genetic and epigenetic regulatory mechanisms underlying human aging and age-related disease will significantly contribute to the developments of new therapeutic interventions for extending health span and life span, ultimately improving the quality of life in the elderly populations.


2021 ◽  
pp. 1-11
Author(s):  
Qiang Wei ◽  
Shanshan Cao ◽  
Yang Ji ◽  
Jun Zhang ◽  
Chen Chen ◽  
...  

Background: The white matter hyperintensities (WMHs) are considered as one of the core neuroimaging findings of cerebral small vessel disease and independently associated with cognitive deficit. The parietal lobe is a heterogeneous area containing many subregions and play an important role in the processes of neurocognition. Objective: To explore the relationship between parietal subregions alterations and cognitive impairments in WHMs. Methods: Resting-state functional connectivity (rs-FC) analyses of parietal subregions were performed in 104 right-handed WMHs patients divided into mild (n = 39), moderate (n = 37), and severe WMHs (n = 28) groups according to the Fazekas scale and 36 healthy controls. Parietal subregions were defined using tractographic Human Brainnetome Atlas and included five subregions for superior parietal lobe, six subregions for inferior parietal lobe (IPL), and three subregions for precuneus. All participants underwent a neuropsychological test battery to evaluate emotional and general cognitive functions. Results: Differences existed between the rs-FC strength of IPL_R_6_2 with the left anterior cingulate gyrus, IPL_R_6_3 with the right dorsolateral superior frontal gyrus, and the IPL_R_6_5 with the left anterior cingulate gyrus. The connectivity strength between IPL_R_6_3 and the left anterior cingulate gyrus were correlated with AVLT-immediate and AVLT-recognition test in WMHs. Conclusion: We explored the roles of parietal subregions in WMHs using rs-FC. The functional connectivity of parietal subregions with the cortex regions showed significant differences between the patients with WMHs and healthy controls which may be associated with cognitive deficits in WMHs.


2021 ◽  
Vol 12 ◽  
Author(s):  
Serena Dato ◽  
Paolina Crocco ◽  
Nicola Rambaldi Migliore ◽  
Francesco Lescai

BackgroundAging is a complex phenotype influenced by a combination of genetic and environmental factors. Although many studies addressed its cellular and physiological age-related changes, the molecular causes of aging remain undetermined. Considering the biological complexity and heterogeneity of the aging process, it is now clear that full understanding of mechanisms underlying aging can only be achieved through the integration of different data types and sources, and with new computational methods capable to achieve such integration.Recent AdvancesIn this review, we show that an omics vision of the age-dependent changes occurring as the individual ages can provide researchers with new opportunities to understand the mechanisms of aging. Combining results from single-cell analysis with systems biology tools would allow building interaction networks and investigate how these networks are perturbed during aging and disease. The development of high-throughput technologies such as next-generation sequencing, proteomics, metabolomics, able to investigate different biological markers and to monitor them simultaneously during the aging process with high accuracy and specificity, represents a unique opportunity offered to biogerontologists today.Critical IssuesAlthough the capacity to produce big data drastically increased over the years, integration, interpretation and sharing of high-throughput data remain major challenges. In this paper we present a survey of the emerging omics approaches in aging research and provide a large collection of datasets and databases as a useful resource for the scientific community to identify causes of aging. We discuss their peculiarities, emphasizing the need for the development of methods focused on the integration of different data types.Future DirectionsWe critically review the contribution of bioinformatics into the omics of aging research, and we propose a few recommendations to boost collaborations and produce new insights. We believe that significant advancements can be achieved by following major developments in bioinformatics, investing in diversity, data sharing and community-driven portable bioinformatics methods. We also argue in favor of more engagement and participation, and we highlight the benefits of new collaborations along these lines. This review aims at being a useful resource for many researchers in the field, and a call for new partnerships in aging research.


2021 ◽  
Author(s):  
Christina Meier ◽  
Parisa Sepehri ◽  
Debbie M. Kelly

Abstract Aging affects individuals of every species, with sometimes detrimental effects on memory and cognition. The simultaneous-chaining task, a sequential-learning task, requires subjects to select items in a predetermined sequence, putting demands on memory and cognitive processing capacity. It is thus a useful tool to investigate age-related differences in these domains. Pigeons of three age groups (young, adult and aged) completed a locomotor adaptation of the task, learning a list of four items. Training began presenting only the first item; additional items were added, one at a time, once previous items were reliably selected in their correct order. Although memory capacity declined noticeably with age, not all aged pigeons showed impairments compared to younger pigeons, suggesting that inter-individual variability emerged with age. During a subsequent free-recall memory test, when all trained items were presented alongside novel distractor items, most pigeons did not reproduce the trained sequence in the absence of reinforcement. During a further forced-choice test, when pigeons were given a choice between only two of the trained items, all three age groups showed evidence of an understanding of the ordinal relationship between items by choosing the earlier item, indicating that complex cognitive processing, unlike memory capacity, remained unaffected by age.


2017 ◽  
Vol 217 (1) ◽  
pp. 65-77 ◽  
Author(s):  
Domhnall McHugh ◽  
Jesús Gil

Aging is the major risk factor for cancer, cardiovascular disease, diabetes, and neurodegenerative disorders. Although we are far from understanding the biological basis of aging, research suggests that targeting the aging process itself could ameliorate many age-related pathologies. Senescence is a cellular response characterized by a stable growth arrest and other phenotypic alterations that include a proinflammatory secretome. Senescence plays roles in normal development, maintains tissue homeostasis, and limits tumor progression. However, senescence has also been implicated as a major cause of age-related disease. In this regard, recent experimental evidence has shown that the genetic or pharmacological ablation of senescent cells extends life span and improves health span. Here, we review the cellular and molecular links between cellular senescence and aging and discuss the novel therapeutic avenues that this connection opens.


Sign in / Sign up

Export Citation Format

Share Document