scholarly journals Age-related changes in the neuromuscular control of forward and backward locomotion

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246372
Author(s):  
Arthur H. Dewolf ◽  
Francesca Sylos-Labini ◽  
Germana Cappellini ◽  
Yury Ivanenko ◽  
Francesco Lacquaniti
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Neuromuscular Control ◽  
Emg Activity ◽  
Intersegmental Coordination ◽  
Backward Walking ◽  
Lower Limb Muscles ◽  
Age Related ◽  
Spatiotemporal Parameters ◽  
Age Related Changes

Previous studies found significant modification in spatiotemporal parameters of backward walking in healthy older adults, but the age-related changes in the neuromuscular control have been considered to a lesser extent. The present study compared the intersegmental coordination, muscle activity and corresponding modifications of spinal montoneuronal output during both forward and backward walking in young and older adults. Ten older and ten young adults walked forward and backward on a treadmill at different speeds. Gait kinematics and EMG activity of 14 unilateral lower-limb muscles were recorded. As compared to young adults, the older ones used shorter steps, a more in-phase shank and foot motion, and the activity profiles of muscles innervated from the sacral segments were significantly wider in each walking condition. These findings highlight age-related changes in the neuromuscular control of both forward and backward walking. A striking feature of backward walking was the differential organization of the spinal output as compared to forward gait. In addition, the resulting spatiotemporal map patterns also characterized age-related changes of gait. Finally, modifications of the intersegmental coordination with aging were greater during backward walking. On the whole, the assessment of backward walk in addition to routine forward walk may help identifying or unmasking neuromuscular adjustments of gait to aging.

scholarly journals Age-related changes in human emotional egocentricity: evidence from multi-level neuroimaging

2019 ◽  
Author(s):  
Federica Riva ◽  
Melanie Lenger ◽  
Martin Kronbichler ◽  
Claus Lamm ◽  
Giorgia Silani
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Life Span ◽  
Emotional State ◽  
Effective Connectivity ◽  
Age Related ◽  
Somatosensory Cortices ◽  
Egocentric Bias ◽  
Multi Level ◽  
Age Related Changes

AbstractEmotional egocentric bias (EEB) occurs when, due to a partial failure in self-other distinction, empathy for another’s emotions is influenced by our own emotional state. Recent studies have demonstrated that this bias is higher in children, adolescents and older adults than in young adults. In the latter, overcoming emotional egocentrism has been associated with significant activity in the right supramarginal gyrus (rSMG), as well as increased connectivity between rSGM and somatosensory and visual cortices. Investigations on the neural correlates of EEB in adolescents and older adults are missing. We filled this gap, by asking female participants from three different age groups (adolescents, young adults and older adults, N=92) to perform a well-validated EEB task (Silani et al., 2013) in an MRI scanner. A multi-level analysis approach of MRI data including functional segregation, effective connectivity and structural analyses was adopted. Results revealed higher EEB in older compared to young adults and a comparable EEB in adolescents and young adults. Age-related differences in EEB were associated with differences in task-related rSMG connectivity with somatosensory cortices, especially with S2, which acted as a partial mediator between age and EEB. These findings provide further evidence for the crucial role of the rSMG in self-other distinction in the emotional domain, and suggest that the age-related decline in overcoming EEB is best explained by changes in rSMG connectivity rather than decreased regional activity in that area. This advocates a more systematic investigation of task-related connectivity in studies on aging and life-span development of social-cognitive phenomena.Significance StatementEmpathy comprises both the ability to identify and share another’s emotional state, and the ability to disentangle one’s own from the other’s emotional state. When self- and other-related emotions are conflicting, empathy might be negatively influenced by egocentric tendencies. This phenomenon is referred to as emotional egocentric bias (EEB), with previous research showing that its extent changes across the life-span. Here, we provide evidence that age-related differences in EEB are mainly associated with age-related changes in rSMG effective connectivity, and in particular that higher EEB in older adults is associated to lower rSMG effective connectivity with somatosensory cortices. These findings suggest the importance, particularly in aging, of intact functional connectivity for optimal socio-cognitive functioning.

scholarly journals I remember it like it was yesterday: Age-related changes in the subjective experience of remembering the past

2020 ◽  
Author(s):  
Adrien Folville ◽  
Jon Simons ◽  
Arnaud D'Argembeau ◽  
Christine Bastin
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Conceptual Knowledge ◽  
Subjective Experience ◽  
Brain Regions ◽  
Future Research ◽  
Subjective Ratings ◽  
Neural Basis ◽  
Age Related ◽  
Age Related Changes

It has been frequently described that older adults subjectively report the vividness of their memories as being as high, or even higher, than young adults, despite poorer objective memory performance and/or lower activity in the associated brain regions. Here, we review studies that examined age-related changes in the cognitive and neural basis of the subjective experience of remembering. Together, these studies reveal that older adults assign subjective memory ratings that are as high or higher than young adults but rely on retrieved memory details to a lesser extent. We discuss potential mechanisms underlying this observation. Overestimation of subjective ratings may stem from metamemory changes, psycho-social factors or methodological issues. As for poorer calibration of the ratings, this may be explained by the fact that older adults rely on/weight other types of information (conceptual knowledge, personal memories, and socioemotional or gist aspects of the memory trace) to a greater extent than young adults when judging the subjective vividness of their memories. We further highlight that a desirable avenue for future research would be to investigate how subjective ratings follow the richness of the corresponding mental representations in other cognitive operations than episodic memory and in other populations than healthy older adults. Finally, we recommend that future studies explore the bases of the subjective sense of remembering across the lifespan while considering recent accounts focusing both on individual and collective/shared aspects of recollection.

scholarly journals Spatial and semantic interference on an auditory Stroop test: comparison of young and older adults

2021 ◽  
Author(s):  
Shubhaganga Dhrruvakumar ◽  
Asha Yathiraj
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Reaction Time ◽  
Spatial Localization ◽  
Stroop Test ◽  
Response Accuracy ◽  
Age Related ◽  
Semantic Localization ◽  
Left Front ◽  
Age Related Changes

Background and Aim: Age related changes in cognitive functioning have been shown to vary depending on the task used. Thus, the study aimed to compare the responses of young and older adults to an auditory Stroop test that asse­ssed spatial (responses to location of the stimuli) and semantic (responses to meaning of the sti­muli) localization. Methods: The “Auditory spatial and semantic localization Stroop test”, developed as a part of the study was administered on 30 young adults aged 18 to 30 years and 30 older adults aged 58 to 70 years having normal hearing. The res­ponse accuracy and reaction time of the parti­cipants were determined for the words “right”, “left”, “front”, and “back.” Results: The older adults had significantly poo­rer response accuracy and reaction time than the young adults for both spatial and semantic loca­lization tasks. Within each participant group, semantic localization had better response accu­racy than spatial localization, while such diffe­rences in reaction time were found only in the older adults. In both groups, a congruency effect was seen for spatial but not for semantic loca­lization when response accuracy was calculated, whereas it was observed only for semantic and not for spatial localization when reaction time was measured. Conclusion: The auditory Stroop test, which measures stimulus interference and cognitive skills, could be used as a simple tool to assess the same for stimuli presented through the audi­tory modality. This would be especially helpful in older adults who may demonstrate cognitive decline with ageing to auditory stimuli. Keywords: Spatial localization; semantic localization; auditory Stroop test; age related changes

Age-Related Changes in Presynaptic Inhibition During Gait Initiation

2021 ◽  
Author(s):  
Solival Santos Filho ◽  
Daniel Boari Coelho ◽  
Carlos Ugrinowitsch ◽  
Caroline Ribeiro de Souza ◽  
Fernando Henrique Magalhães ◽  
...  
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Presynaptic Inhibition ◽  
Gait Initiation ◽  
Quiet Stance ◽  
Age Related ◽  
Contraction Ratio ◽  
Age Range ◽  
Age Related Changes ◽  
Presynaptic Control

Abstract Age-related changes in presynaptic inhibition (PSI) have not been observed during gait initiation, which requires anticipatory postural adjustment (APA). As APA is centrally modulated and is impaired in older compared to young adults, here we aimed to study the presynaptic control and co-contraction levels in the ankle muscles during gait initiation in older compared to young adults. Fifteen older (age range 65–80 years) and 15 young adults (age range 19–30 years) performed a gait initiation task on a force platform under 3 conditions: (i) without electrical stimulation; (ii) test Hoffman reflex (H-reflex); and (iii) conditioned H-reflex. H-reflexes were evoked on the soleus muscle when the APA amplitude exceeded 10%–20% of the average baseline mediolateral force. Participants also performed quiet stance as a control task. Results showed that both age groups presented similar PSI levels during quiet stance (p = .941), while in the gait initiation older adults presented higher PSI levels, longer duration, and lower amplitude of APA than young adults (p < .05). Older adults presented higher co-contraction ratio in both tasks than young adults (p < .05). Correlations between the PSI levels and the APA amplitude (r = −0.61, p = .008), and between the PSI levels and the co-contraction ratio during gait initiation (r = −0.64, p = .005) were found for older adults only. APA amplitude explained 49% of the variance of the PSI levels (p = .003). Our findings suggest that older compared to young adults have increased presynaptic control to compensate for the decreased supraspinal modulation on impaired APAs during gait initiation.

scholarly journals Revisiting the Age-Prospective Memory Paradox Using Laboratory and Ecological Tasks

2021 ◽  
Vol 12 ◽  
Author(s):  
Yu Wen Koo ◽  
David L. Neumann ◽  
Tamara Ownsworth ◽  
David H. K. Shum
Keyword(s):  
Older Adults ◽  
Working Memory ◽  
Young Adults ◽  
Prospective Memory ◽  
Community Dwelling ◽  
Cognitive Factors ◽  
Future Time ◽  
Age Related ◽  
Community Dwelling Older Adults ◽  
Age Related Changes

Prospective memory (PM) is the ability to perform a planned action at a future time. Older adults have shown moderate declines in PM, which are thought to be driven by age-related changes in the prefrontal cortex. However, an age-PM paradox is often reported, whereby deficits are evident in laboratory-based PM tasks, but not naturalistic PM tasks. The key aims of this study were to: (1) examine the age-PM paradox using the same sample across laboratory and ecological settings; and (2) determine whether self-reported PM and cognitive factors such as working memory and IQ are associated PM performance. Two PM tasks were administered (ecological vs. laboratory) to a sample of 23 community-dwelling older adults (Mage = 72.30, SDage = 5.62) and 28 young adults (Mage = 20.18, SDage = 3.30). Participants also completed measures of general cognitive function, working memory, IQ, and self-reported memory. Our results did not support the existence of the age-PM paradox. Strong age effects across both laboratory and ecological PM tasks were observed in which older adults consistently performed worse on the PM tasks than young adults. In addition, PM performance was significantly associated with self-reported PM measures in young adults. For older adults, IQ was associated with time-based PM. These findings suggest that the age-PM paradox is more complex than first thought and there are differential predictors of PM performance for younger and older adults.

scholarly journals Gravity effects are better optimized by older than young adults when reaching with the non-dominant arm

2021 ◽  
Author(s):  
Gabriel Poirier ◽  
Charalambos Papaxanthis ◽  
Adrien Juranville ◽  
Mélanie Lebigre ◽  
France Mourey ◽  
...  
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Motor Control ◽  
Control Process ◽  
Open Loop ◽  
Emg Activity ◽  
Aging Effects ◽  
Arm Kinematics ◽  
Age Related ◽  
Gravity Effects

Motor lateralization refers to differences in the neural organization of cerebral hemispheres, resulting in different control specializations between the dominant and the non-dominant motor systems. Multiple studies proposed that the dominant hemisphere is specialized for open-loop optimization-like processes. Recently, comparing arm kinematics between upward and downward movements, we found that the dominant arm outperformed the non-dominant one regarding gravity-related motor optimization in healthy young subjects. The literature about aging effects on motor control presents several neurophysiological and behavioral evidences for an age-related reduction of motor lateralization. Here, we compare the lateralization of a well-known gravity-related optimal motor control process between young and older adults. Thirty healthy young (mean age = 24.1 ± 3 years) and nineteen healthy older adults (mean age = 73.0 ± 8) performed single degree-of-freedom vertical arm movements between two targets (upward and downward). Participants alternatively reached with their dominant and non-dominant arms. We recorded arm kinematics and electromyographic activities of the prime movers (Anterior and Posterior Deltoids) and we analyzed parameters thought to represent the hallmark of the gravity-related optimization process (i.e directional asymmetries and negative epochs on the phasic EMG activity). We found no arm difference in older participants, such that parameters with both arms were similar to those of young participants with their dominant arm. With the non-dominant arm, these results suggest that older adults better optimize gravity effects than young adults.

scholarly journals Age-related Changes in the Sleep-dependent Reorganization of Declarative Memories

2016 ◽  
Vol 28 (6) ◽  
pp. 792-802 ◽  
Author(s):  
Bengi Baran ◽  
Janna Mantua ◽  
Rebecca M. C. Spencer
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Functional Connectivity ◽  
Memory Retrieval ◽  
Slow Wave Sleep ◽  
Memory Performance ◽  
Memory Recall ◽  
Functional Brain ◽  
Age Related ◽  
Age Related Changes

Consolidation of declarative memories has been associated with slow wave sleep in young adults. Previous work suggests that, in spite of changes in sleep, sleep-dependent consolidation of declarative memories may be preserved with aging, although reduced relative to young adults. Previous work on young adults shows that, with consolidation, retrieval of declarative memories gradually becomes independent of the hippocampus. To investigate whether memories are similarly reorganized over sleep at the neural level, we compared functional brain activation associated with word pair recall following a nap and equivalent wake in young and older adults. SWS during the nap predicted better subsequent memory recall and was negatively associated with retrieval-related hippocampal activation in young adults. In contrast, in older adults there was no relationship between sleep and memory performance or with retrieval-related hippocampal activation. Furthermore, compared with young adults, postnap memory retrieval in older adults required strong functional connectivity of the hippocampus with the PFC, whereas there were no differences between young and older adults in the functional connectivity of the hippocampus following wakefulness. These results suggest that, although neural reorganization takes place over sleep in older adults, the shift is unique from that seen in young adults, perhaps reflecting memories at an earlier stage of stabilization.

scholarly journals Neuromuscular Age-Related Adjustment of Gait When Moving Upwards and Downwards

2021 ◽  
Vol 15 ◽  
Author(s):  
Arthur H. Dewolf ◽  
Francesca Sylos-Labini ◽  
Germana Cappellini ◽  
Dmitry Zhvansky ◽  
Patrick A. Willems ◽  
...  
Keyword(s):  
Older Adults ◽  
Neuromuscular Control ◽  
Negative Slope ◽  
Centre Of Mass ◽  
Lower Limb Muscles ◽  
Transition Strategy ◽  
Age Related ◽  
Support Surfaces ◽  
Step Transition ◽  
Full Body

Locomotor movements are accommodated to various surface conditions by means of specific locomotor adjustments. This study examined underlying age-related differences in neuromuscular control during level walking and on a positive or negative slope, and during stepping upstairs and downstairs. Ten elderly and eight young adults walked on a treadmill at two different speeds and at three different inclinations (0°, +6°, and −6°). They were also asked to ascend and descend stairs at self-selected speeds. Full body kinematics and surface electromyography of 12 lower-limb muscles were recorded. We compared the intersegmental coordination, muscle activity, and corresponding modifications of spinal motoneuronal output in young and older adults. Despite great similarity between the neuromuscular control of young and older adults, our findings highlight subtle age-related differences in all conditions, potentially reflecting systematic age-related adjustments of the neuromuscular control of locomotion across various support surfaces. The main distinctive feature of walking in older adults is a significantly wider and earlier activation of muscles innervated by the sacral segments. These changes in neuromuscular control are reflected in a reduction or lack of propulsion observed at the end of stance in older adults at different slopes, with the result of a delay in the timing of redirection of the centre-of-mass velocity and of an unanticipated step-to-step transition strategy.

Inefficient Encoding as an Explanation for Age-Related Deficits in Recollection-Based Processing

2014 ◽  
Vol 28 (3) ◽  
pp. 148-161 ◽  
Author(s):  
David Friedman ◽  
Ray Johnson
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Cognitive Processes ◽  
Brain Activity ◽  
Memory Performance ◽  
Brain Regions ◽  
Semantic Retrieval ◽  
Age Related ◽  
The Face ◽  
Episodic Memories

A cardinal feature of aging is a decline in episodic memory (EM). Nevertheless, there is evidence that some older adults may be able to “compensate” for failures in recollection-based processing by recruiting brain regions and cognitive processes not normally recruited by the young. We review the evidence suggesting that age-related declines in EM performance and recollection-related brain activity (left-parietal EM effect; LPEM) are due to altered processing at encoding. We describe results from our laboratory on differences in encoding- and retrieval-related activity between young and older adults. We then show that, relative to the young, in older adults brain activity at encoding is reduced over a brain region believed to be crucial for successful semantic elaboration in a 400–1,400-ms interval (left inferior prefrontal cortex, LIPFC; Johnson, Nessler, & Friedman, 2013 ; Nessler, Friedman, Johnson, & Bersick, 2007 ; Nessler, Johnson, Bersick, & Friedman, 2006 ). This reduced brain activity is associated with diminished subsequent recognition-memory performance and the LPEM at retrieval. We provide evidence for this premise by demonstrating that disrupting encoding-related processes during this 400–1,400-ms interval in young adults affords causal support for the hypothesis that the reduction over LIPFC during encoding produces the hallmarks of an age-related EM deficit: normal semantic retrieval at encoding, reduced subsequent episodic recognition accuracy, free recall, and the LPEM. Finally, we show that the reduced LPEM in young adults is associated with “additional” brain activity over similar brain areas as those activated when older adults show deficient retrieval. Hence, rather than supporting the compensation hypothesis, these data are more consistent with the scaffolding hypothesis, in which the recruitment of additional cognitive processes is an adaptive response across the life span in the face of momentary increases in task demand due to poorly-encoded episodic memories.

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