scholarly journals Effects of Aging on Feedforward Postural Synergies

2008 ◽  
Vol 20 (1) ◽  
pp. 63-70 ◽  
Author(s):  
Tadayoshi Asaka ◽  
Yun Wang
Keyword(s):  
Time Lag ◽  
Principal Component ◽  
Young Group ◽  
Co Activation ◽  
Extensor Muscles ◽  
Postural Muscle ◽  
Older Subjects ◽  
Effects Of Aging ◽  
Postural Synergies ◽  
Muscle Modes

Effects of Aging on Feedforward Postural SynergiesWe investigated the effects of aging on postural muscles covariate patterns prior to voluntary perturbations. Nine healthy young and nine older subjects were instructed to release a load in a self-paced manner. The results of cross-correlation analyses showed that the average time lag corresponding peak correlation coefficient between trunk flexor and extensor muscles in the older group was significantly shorter, compared to that in the young group. The results of principal component analysis showed that the co-contraction Muscle-modes in the older group were observed more frequently than those in the young group. These results indicate that the older group showed changes in the anticipatory postural muscle co-variation, suggesting the transition from reciprocal to co-activation pattern with aging.

Effects of aging on sensation of respiratory force and displacement

1983 ◽  
Vol 55 (5) ◽  
pp. 1433-1440 ◽  
Author(s):  
M. Tack ◽  
M. D. Altose ◽  
N. S. Cherniack
Keyword(s):  
Tidal Volume ◽  
Lung Volume ◽  
Young Group ◽  
Magnitude Production ◽  
Volume Changes ◽  
Older Subjects ◽  
Young Subjects ◽  
Function Relationship ◽  
Effects Of Aging ◽  
Force Scaling

The psychophysical technique of magnitude production was used to evaluate the sensation of inspiratory force and inspired volume in young and older subjects. Inspiratory force was generated during a static inspiratory maneuver against a closed airway. The exponent of the power function relationship between airway pressure and sensation intensity during force scaling was not significantly different between young and older subjects. In contrast, the exponents for the magnitude production of inspired volume were significantly greater in the older compared with the young group. We also assessed the effects of age on the relative importance of force and displacement signals on the sensation of inspired volume. Subjects attempted to reproduce a control tidal volume while breathing against a series of inspiratory resistive and elastic loads. In both groups error in tidal volume reproduction increased progressively as the severity of the load increased. During moderate and severe loading the error in the older subjects was significantly greater than in the young group. Correspondingly, the peak inspiratory airway pressures at tidal volume reproduction against these loads were significantly smaller in the older compared with the young subjects. The results suggest that in older subjects cues related to respiratory muscle force are more important than volume in the sensation of lung volume changes. In young subjects the sensation of lung volume changes is based to a greater degree on signals of volume or displacement.

scholarly journals Influence of age and gender on the profile of exhaled volatile organic compounds analyzed by an electronic nose

2016 ◽  
Vol 42 (2) ◽  
pp. 143-145 ◽  
Author(s):  
Silvano Dragonieri ◽  
Vitaliano Nicola Quaranta ◽  
Pierluigi Carratu ◽  
Teresa Ranieri ◽  
Onofrio Resta
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Electronic Nose ◽  
Principal Component ◽  
Exhaled Breath ◽  
Age And Gender ◽  
Volatile Organic ◽  
Older Subjects ◽  
Never Smokers ◽  
And Gender

We aimed to investigate the effects of age and gender on the profile of exhaled volatile organic compounds. We evaluated 68 healthy adult never-smokers, comparing them by age and by gender. Exhaled breath samples were analyzed by an electronic nose (e-nose), resulting in "breathprints". Principal component analysis and canonical discriminant analysis showed that older subjects (≥ 50 years of age) could not be distinguished from younger subjects on the basis of their breathprints, as well as that the breathprints of males could not distinguished from those of females (cross-validated accuracy, 60.3% and 57.4%, respectively).Therefore, age and gender do not seem to affect the overall profile of exhaled volatile organic compounds measured by an e-nose.

scholarly journals Exploring the Predictability of 30-Day Extreme Precipitation Occurrence Using a Global SST–SLP Correlation Network

2016 ◽  
Vol 29 (3) ◽  
pp. 1013-1029 ◽  
Author(s):  
Mengqian Lu ◽  
Upmanu Lall ◽  
Jaya Kawale ◽  
Stefan Liess ◽  
Vipin Kumar
Keyword(s):  
Extreme Precipitation ◽  
Time Lag ◽  
Principal Component Regression ◽  
Principal Component ◽  
Correlation Network ◽  
Climatic Data ◽  
Wet Season ◽  
Predictive Skill ◽  
Correlation Networks ◽  
Time Lagged

Abstract Correlation networks identified from financial, genomic, ecological, epidemiological, social, and climatic data are being used to provide useful topological insights into the structure of high-dimensional data. Strong convection over the oceans and the atmospheric moisture transport and flow convergence indicated by atmospheric pressure fields may determine where and when extreme precipitation occurs. Here, the spatiotemporal relationship among sea surface temperature (SST), sea level pressure (SLP), and extreme global precipitation is explored using a graph-based approach that uses the concept of reciprocity to generate cluster pairs of locations with similar spatiotemporal patterns at any time lag. A global time-lagged relationship between pentad SST anomalies and pentad SLP anomalies is investigated to understand the linkages and influence of the slowly changing oceanic boundary conditions on the development of the global atmospheric circulation. This study explores the use of this correlation network to predict extreme precipitation globally over the next 30 days, using a logistic principal component regression on the strong global dipoles found between SST and SLP. Predictive skill under cross validation and blind prediction for the occurrence of 30-day precipitation that is higher than the 90th percentile of days in the wet season is indicated for the selected global regions considered.

Intersegmental reflex actions from a joint sensory organ (CB) to a muscle receptor (MCO) in decapod crustacean limbs

1978 ◽  
Vol 73 (1) ◽  
pp. 47-63 ◽  
Author(s):  
B. M. Bush ◽  
J. P. Vedel ◽  
F. Clarac
Keyword(s):  
Decapod Crustacean ◽  
Extensor Muscle ◽  
Chordotonal Organ ◽  
Flexor Muscle ◽  
Proprioceptive Reflexes ◽  
Co Activation ◽  
Extensor Muscles ◽  
Motor Activities ◽  
Central Excitability ◽  
Reflex Discharge

In the walking legs of decapod crustaceans, intersegmental reflex actions originate from various joint proprioceptors. The activity of the ‘accessory flexor’ (AF) muscle, which with the myochordotonal organ (MCO) constitutes a muscle proprioceptor for the mero-carpopodite (M-C) joint, is modulated by the sensory discharge of a joint receptor (CB chordotonal organ) for the more proximal, coxo-basal (C-B) joint. Selective mechanical stimulation of the CB organ also reflexly modifies the motor activities of the main M-C flexor and extensor muscles (recorded as EMGs). 1. Dynamic CB stretch (as would occur during a dorso-ventral C-B movement - i.e. ‘depression’ of the limb) stimulates motor discharge to the M-C extensor muscle, while dynamic release of CB (as during a ventrodorsal C-B movement - or leg ‘elevation’) excites the accessory flexor as well as the main flexor muscle. 2. Successive M-C muscle responses to repetitive sinusoidal changes of CB length differ quantitatively according to the direction (stretch or release) of the first CB movement, in some cases increasing but more commonly ‘adapting’ with repetition. 3. Reflex discharge frequencies of the extensor, flexor and accessory flexor motoneurones increase with velocity of CB movement. 4. Eye illumination, and spontaneous or other sources of increased central excitability, generally increase the CB reflex drive to the flexor and accessory flexor muscles and, in parallel, decrease the reflex action on the extensor muscle. The results are discussed in terms of the role of proprioceptive reflexes in intersegmental co-ordination of the leg joints. In particular the significance of the reflex regulation of the myochordotonal receptors, and thereby the gain of the M-C resistance reflexes, is considered in the light of the observed ‘co-activation’ of main flexor and receptor muscle motoneurones.

Within-day and between-day chlorophyll a dynamics during summer in Guanting Reservoir, Beijing, China

2020 ◽  
Author(s):  
Jiang Weiwei ◽  
Yu Jingshan
Keyword(s):  
Water Temperature ◽  
Chlorophyll A ◽  
Meteorological Factors ◽  
Time Lag ◽  
Principal Component ◽  
Chl A ◽  
Guanting Reservoir ◽  
Vertical Scale ◽  
Concentration Layer ◽  
Beijing China

<p>Recognizing intra- and inter-daily dynamics of Chlorophyll a (Chl-a) and its related environmental variables in consecutive days play an important role in assessing and managing water quality and eutrophication. In this study, the water temperature, nutrients, Chl-a concentration  and meteorological factors were collected at six sampling times in Guanting reservoir during summer. Chl-a concentration generally decreased from last May to primary September. At both test times, thermal stratification and mixing in the water column controlled the variation of maximum Chl-a concentration layer at both temporal and vertical scale. The position of the maximum Chl-a concentration layer between days generally followed the same dynamics as thermocline. Daily stratifications were temporary and maximum Chl-a concentration layer varies downwelling by wind driven; hence, the vertical distribution of Chl-a concentration was homogenized at night. Surface Chl-a concentration decreased during the day and increased at night, except on rainy days. The results of Person correlations and principal component analysis indicated that raw surface and daily average Chl-a concentration generally changed as a negative function of solar radiation, wind speed, water temperature and air temperature. However, when a five hour time lag is considered, the relationship between surface Chl-a concentration, water temperature and all meteorological factors became significantly positive.</p>

Differential Effects of Aging on Two Verbal Fluency Tasks

1993 ◽  
Vol 76 (2) ◽  
pp. 465-466 ◽  
Author(s):  
Rachel Tomer ◽  
Bonnie E. Levin
Keyword(s):  
Healthy Volunteers ◽  
Verbal Fluency ◽  
Semantic Category ◽  
Semantic Fluency ◽  
Alzheimer Type ◽  
Differential Effects ◽  
Alzheimer Type Dementia ◽  
Older Subjects ◽  
Effects Of Aging ◽  
Effect Of Age

The effect of age on verbal fluency was studied in 84 healthy volunteers, ages 45 to 91 years, who performed letter-fluency and semantic-fluency tasks. Older subjects (75 to 91 yr.) performed as well as younger (50 to 64 yr.) on letter fluency but did significantly worse on semantic category fluency. This pattern is similar to that observed in Alzheimer-type dementia.

scholarly journals Aging does not affect the intralimb coordination elicited by slip-like perturbation of different intensities

2017 ◽  
Vol 118 (3) ◽  
pp. 1739-1748 ◽  
Author(s):  
Federica Aprigliano ◽  
Dario Martelli ◽  
Peppino Tropea ◽  
Guido Pasquini ◽  
Silvestro Micera ◽  
...  
Keyword(s):  
Lower Limb ◽  
Balance Control ◽  
Principal Component ◽  
Elderly Subjects ◽  
Coordination Strategy ◽  
Age Related ◽  
Control Schemes ◽  
Intralimb Coordination ◽  
Older Subjects ◽  
Spatio Temporal

This study was aimed at verifying whether aging modifies intralimb coordination strategy during corrective responses elicited by unexpected slip-like perturbations delivered during steady walking on a treadmill. To this end, 10 young and 10 elderly subjects were asked to manage unexpected slippages of different intensities. We analyzed the planar covariation law of the lower limb segments, using the principal component analysis, to verify whether elevation angles of older subjects covaried along a plan before and after the perturbation. Results showed that segments related to the perturbed limbs of both younger and older people do not covary after all perturbations. Conversely, the planar covariation law of the unperturbed limb was systematically held for younger and older subjects. These results occurred despite differences in spatio-temporal and kinematic parameters being observed among groups and perturbation intensities. Overall, our analysis revealed that aging does not affect intralimb coordination during corrective responses induced by slip-like perturbation, suggesting that both younger and older subjects adopt this control strategy while managing sudden and unexpected postural transitions of increasing intensities. Accordingly, results corroborate the hypothesis that balance control emerges from a governing set of biomechanical invariants, that is, suitable control schemes (e.g., planar covariation law) shared across voluntary and corrective motor behaviors, and across different sensory contexts due to different perturbation intensities, in both younger and older subjects. In this respect, our findings provide further support to investigate the effects of specific task training programs to counteract the risk of fall. NEW & NOTEWORTHY This study was aimed at investigating how aging affects the intralimb coordination of lower limb segments, described by the planar covariation law, during unexpected slip-like perturbations of increasing intensity. Results revealed that neither the aging nor the perturbation intensity affects this coordination strategy. Accordingly, we proposed that the balance control emerges from an invariant set of control schemes shared across different sensory motor contexts and despite age-related neuromuscular adaptations.

Instigation and control of treadmill locomotion in high decerebrate cats by stimulation of the hook bundle of Russell in the cerebellum

2000 ◽  
Vol 78 (11) ◽  
pp. 945-957 ◽  
Author(s):  
Shigemi Mori ◽  
Toshihiro Matsui ◽  
Futoshi Mori ◽  
Katsumi Nakajima ◽  
Kiyoji Matsuyama
Keyword(s):  
Muscle Tone ◽  
Fastigial Nucleus ◽  
Extensor Muscles ◽  
Upper Cervical ◽  
Postural Muscle ◽  
Restricted Region ◽  
Vestibular Complex ◽  
Parallel Activation ◽  
And Control ◽  
Decerebrate Cats

In high decerebrate cats, pulse train microstimulation of a restricted region of the midline cerebellar white matter produced a generalized increase in postural muscle tone in the neck, trunk, and limb extensor muscles, and air-stepping of all four legs on a stationary surface. On the moving belt of a treadmill, such stimulation produced well coordinated, fore- and hindlimb locomotion as evoked by stimulating the mesencephalic locomotor region (MLR). Microinjection of a neural tracer into the cerebellar locomotion-inducing site resulted in a bilateral retrograde labeling of cells limited to the fastigial nuclei simultaneously with anterograde labeling of fibers projecting bilaterally to the medial pontomedullary reticular formation (mPMRF) the vestibular complex and upper cervical segments. These results have led to our proposition that the effective cerebellar locomotor region (CLR) corresponds to the midline region of the hook bundle of Russell. Passing through this structure are crossed fastigioreticular and fastigiovestibular fibers, together with fastigiospinal fibers. Subsequently, we showed that CLR stimulation resulted in simultaneous short-latency synaptic activation of long-descending reticulospinal and vestibulospinal cells with high synaptic security. Clearly, the fastigial nucleus possesses potential capability to recruit and regulate posture- and locomotor-related subprograms which are distributed within the brainstem and spinal cord by the in-parallel activation of fastigiospinal, fastigioreticular, and fastigiovestibular pathways.Key words: cerebellar locomotor region (CLR), fastigial nucleus, hook bundle of Russell, reticulospinal cell, vestibulospinal cell.

Rho kinase-mediated local cold-induced cutaneous vasoconstriction is augmented in aged human skin

2007 ◽  
Vol 293 (1) ◽  
pp. H30-H36 ◽  
Author(s):  
Caitlin S. Thompson-Torgerson ◽  
Lacy A. Holowatz ◽  
Nicholas A. Flavahan ◽  
W. Larry Kenney
Keyword(s):  
Rho Kinase ◽  
Age Difference ◽  
Local Cooling ◽  
Kinase Inhibition ◽  
Doppler Flowmetry ◽  
Forearm Skin ◽  
Older Subjects ◽  
Young Subjects ◽  
Effects Of Aging ◽  
Cutaneous Vasoconstriction

Cutaneous vasoconstriction (VC), a critical thermoregulatory response to cold, is generally impaired with aging. However, the effects of aging on local cooling-induced VC and its underlying mechanisms are poorly understood. We tested whether aged skin exhibits attenuated localized cold-induced VC and whether Rho kinase-mediated cold-induced VC is augmented with age. Skin blood flow was monitored with laser Doppler flowmetry (LDF) on seven young and seven older subjects. Cutaneous vascular conductance (CVC; LDF/mean arterial pressure) was expressed as percentage change from baseline (%ΔCVCbase). In protocol 1, two forearm skin sites were cooled to six temperatures (31.5–19°C) for 10 min each or two temperatures (29°C, 24°C) for 30 min each, with no age differences in the magnitude of VC. In protocol 2, three forearm skin sites were instrumented for intradermal microdialysis and cooled to 24°C for 40 min. During minutes 1–5, there was no age difference in CVC responses at control sites (young: −45 ± 6% vs. older: −46 ± 3%, P > 0.9). Adrenoceptor antagonism (yohimbine + propranolol) abolished VC in young (to +15 ± 13%, P < 0.05) but only partially inhibited VC in older subjects (to −23 ± 6%, P < 0.05). Rho kinase inhibition plus adrenoceptor antagonism (yohimbine + propranolol + fasudil) abolished VC in both groups. During minutes 35–40, there was no age difference in control (young: −77 ± 4% vs. older: −70 ± 2%, P > 0.3) or adrenoceptor-antagonized responses (young: −61 ± 3% vs. older: −55 ± 2%, P > 0.3); however, Rho kinase inhibition plus adrenoceptor antagonism blocked more VC in older compared with young subjects (−19 ± 11% vs. −35 ± 3%, P < 0.05). Although its magnitude remains unaffected, cold-induced VC becomes less dependent on adrenergic and more dependent on Rho kinase signaling with advancing age.

scholarly journals A Noninvasive Accurate Measurement of Blood Glucose Levels with Raman Spectroscopy of Blood in Microvessels

Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1500 ◽  
Author(s):  
Nan Li ◽  
Hang Zang ◽  
Huimin Sun ◽  
Xianzhi Jiao ◽  
Kangkang Wang ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Blood Glucose ◽  
Raman Spectra ◽  
Interstitial Fluid ◽  
Time Lag ◽  
Back Propagation ◽  
Principal Component ◽  
Oral Glucose ◽  
Multiple Characteristic ◽  
Non Invasive

Raman spectra of human skin obtained by laser excitation have been used to non-invasively detect blood glucose. In previous reports, however, Raman spectra thus obtained were mainly derived from the epidermis and interstitial fluid as a result of the shallow penetration depth of lasers in skin. The physiological process by which glucose in microvessels penetrates into the interstitial fluid introduces a time delay, which inevitably introduces errors in transcutaneous measurements of blood glucose. We focused the laser directly on the microvessels in the superficial layer of the human nailfold, and acquired Raman spectra with multiple characteristic peaks of blood, which indicated that the spectra obtained predominantly originated from blood. Incorporating a multivariate approach combining principal component analysis (PCA) and back propagation artificial neural network (BP-ANN), we performed noninvasive blood glucose measurements on 12 randomly selected volunteers, respectively. The mean prediction performance of the 12 volunteers was obtained as an RMSEP of 0.45 mmol/L and R2 of 0.95. It was no time lag between the predicted blood glucose and the actual blood glucose in the oral glucose tolerance test (OGTT). We also applied the procedure to data from all 12 volunteers regarded as one set, and the total predicted performance was obtained with an RMSEP of 0.27 mmol/L and an R2 of 0.98, which is better than that of the individual model for each volunteer. This suggested that anatomical differences between volunteer fingernails do not reduce the prediction accuracy and 100% of the predicted glucose concentrations fall within Region A and B of the Clarke error grid, allowing acceptable predictions in a clinically relevant range. The Raman spectroscopy detection of blood glucose from microvessels is of great significance of non-invasive blood glucose detection of Raman spectroscopy. This innovative method may also facilitate non-invasive detection of other blood components.

Sign in / Sign up

Export Citation Format

Share Document