Reversal of Age-Related Changes in Cortical Sound-Azimuth Selectivity with Training

2019 ◽  
Vol 30 (3) ◽  
pp. 1768-1778
Author(s):  
Yuan Cheng ◽  
Yifan Zhang ◽  
Fang Wang ◽  
Guoqiang Jia ◽  
Jie Zhou ◽  
...  
Keyword(s):  
Auditory Perception ◽  
Task Demands ◽  
Auditory Training ◽  
Spatial Processing ◽  
Inhibitory Interneurons ◽  
Older Individuals ◽  
Behavioral Training ◽  
Age Related ◽  
Old Rats ◽  
Age Related Changes

Abstract The compromised abilities to understand speech and localize sounds are two hallmark deficits in aged individuals. Earlier studies have shown that age-related deficits in cortical neural timing, which is clearly associated with speech perception, can be partially reversed with auditory training. However, whether training can reverse aged-related cortical changes in the domain of spatial processing has never been studied. In this study, we examined cortical spatial processing in ~21-month-old rats that were trained on a sound-azimuth discrimination task. We found that animals that experienced 1 month of training displayed sharper cortical sound-azimuth tuning when compared to the age-matched untrained controls. This training-induced remodeling in spatial tuning was paralleled by increases of cortical parvalbumin-labeled inhibitory interneurons. However, no measurable changes in cortical spatial processing were recorded in age-matched animals that were passively exposed to training sounds with no task demands. These results that demonstrate the effects of training on cortical spatial domain processing in the rodent model further support the notion that age-related changes in central neural process are, due to their plastic nature, reversible. Moreover, the results offer the encouraging possibility that behavioral training might be used to attenuate declines in auditory perception, which are commonly observed in older individuals.

scholarly journals Age-related reductions in the number of serial sarcomeres contribute to shorter fascicle lengths but not elevated passive tension

2020 ◽  
Author(s):  
Geoffrey A. Power ◽  
Sean Crooks ◽  
Jared R. Fletcher ◽  
Brian R. Macintosh ◽  
Walter Herzog
Keyword(s):  
Muscle Length ◽  
Medial Gastrocnemius ◽  
Slight Reduction ◽  
Passive Tension ◽  
Passive Force ◽  
Older Individuals ◽  
Age Related ◽  
Old Rats ◽  
Length Changes ◽  
Age Related Changes

AbstractWe investigated age-related changes to fascicle length (FL), sarcomere length (SL), and serial sarcomere number (SSN), and how this affects passive force. Following mechanical testing to determine passive force, the medial gastrocnemius muscle of young (n=9) and old (n=8) Fisher 344BN hybrid rats was chemically fixed at the optimal muscle length for force production; individual fascicles were dissected for length measurement, and laser diffraction was used to assess SL. Old rats had ∼14% shorter FL than young, which was driven by a ∼10% reduction in SSN, with no difference in SL (∼4%). Passive force was greater in the old compared to young rats at long muscle lengths. Shorter FL and reduced SSN in the old rats could not entirely explain increased passive forces for absolute length changes, owing to a slight reduction in SL in old, resulting in similar SL at long muscle lengths.Summary StatementThis study sought to explain the increased passive tension observed for muscles of older individuals owing to age-related changes to muscle architecture.

Age-related changes in endothelial permeability and distribution volume of albumin in rat aorta

1993 ◽  
Vol 264 (3) ◽  
pp. H679-H685 ◽  
Author(s):  
J. Belmin ◽  
B. Corman ◽  
R. Merval ◽  
A. Tedgui
Keyword(s):  
Arterial Wall ◽  
Relative Concentration ◽  
Endothelial Permeability ◽  
Distribution Volume ◽  
Albumin Concentration ◽  
Macromolecular Transport ◽  
Age Related ◽  
The Media ◽  
Old Rats ◽  
Age Related Changes

Age-related changes in macromolecular transport across the arterial wall were investigated in 10-, 20-, and 30-mo-old WAG/Rij rats. Animals were injected with 125I- and 131I-labeled albumin, 90 and 5 min before they were killed, respectively. The transmural distribution of relative concentration of tracers in the aortic wall was obtained using en face serial sectioning technique. The apparent endothelial permeability to albumin calculated from the distribution of 5-min 131I-labeled albumin concentrations was significantly enhanced in 20- and 30-mo-old rats compared with 10-mo-old rats. The apparent distribution volume of albumin within the media, estimated as the mean medial 125I-labeled albumin concentration, was not significantly changed in 20-mo-old rats but was significantly decreased in the 30-mo-old animals. These age-related changes in the macromolecular transport suggest that the entry of plasma macromolecules in the aged arterial wall might be enhanced, whereas the efflux through the media may be impeded, possibly contributing to their trapping in the subendothelium.

scholarly journals Pairing Cholinergic Enhancement with Perceptual Training Promotes Recovery of Age-Related Changes in Rat Primary Auditory Cortex

2016 ◽  
Vol 2016 ◽  
pp. 1-18 ◽  
Author(s):  
Patrice Voss ◽  
Maryse Thomas ◽  
You Chien Chou ◽  
José Miguel Cisneros-Franco ◽  
Lydia Ouellet ◽  
...  
Keyword(s):  
Auditory Cortex ◽  
Structural Changes ◽  
Primary Auditory Cortex ◽  
Auditory Training ◽  
Tone Frequency ◽  
Perceptual Training ◽  
Adult Rats ◽  
Functional Changes ◽  
Age Related ◽  
Old Rats

We used the rat primary auditory cortex (A1) as a model to probe the effects of cholinergic enhancement on perceptual learning and auditory processing mechanisms in both young and old animals. Rats learned to perform a two-tone frequency discrimination task over the course of two weeks, combined with either the administration of a cholinesterase inhibitor or saline. We found that while both age groups learned the task more quickly through cholinergic enhancement, the young did so by improving target detection, whereas the old did so by inhibiting erroneous responses to nontarget stimuli. We also found that cholinergic enhancement led to marked functional and structural changes within A1 in both young and old rats. Importantly, we found that several functional changes observed in the old rats, particularly those relating to the processing and inhibition of nontargets, produced cortical processing features that resembled those of young untrained rats more so than those of older adult rats. Overall, these findings demonstrate that combining auditory training with neuromodulation of the cholinergic system can restore many of the auditory cortical functional deficits observed as a result of normal aging and add to the growing body of evidence demonstrating that many age-related perceptual and neuroplastic changes are reversible.

Age-related changes in substance P-immunoreactive nerve structures of the rat recto-anal region

Open Medicine ◽  
2010 ◽  
Vol 5 (3) ◽  
pp. 358-364
Author(s):  
Nikolai Lazarov ◽  
Dimitar Itzev ◽  
Kamen Usunoff ◽  
Negrin Negrev ◽  
Radomir Radomirov
Keyword(s):  
Substance P ◽  
Anal Sphincter ◽  
Internal Anal Sphincter ◽  
Circular Muscle ◽  
Muscle Layer ◽  
Nerve Fibres ◽  
Anal Region ◽  
Age Related ◽  
Old Rats ◽  
Age Related Changes

AbstractThe recto-anal region is innervated by extrinsic and intrinsic nerves and a number of neuropeptides including substance P (SP) have been suggested to participate in the regulation of intestinal movements. We examined the age-related changes in the distribution of SP-immunoreactive nerve structures in the distal part of the rat large intestine. Using immunohistochemistry, the presence of SP was studied in fresh tissues from Wistar rats at different ages taken at three sampling sites, the distal rectum, anal canal and internal anal sphincter. In the 15-day old rats the myenteric plexus of the distal rectum and anal canal was well outlined by numerous SP-immunoreactive varicose nerve fibres encircling immunonegative perikarya. In the circular muscle layer, nerve fibres and small nerve bundles ran parallel to the muscle cells, while in the longitudinal muscle layer, only occasional nerve fibres were seen. At the level of the internal anal sphincter, no myenteric ganglia were present. Here, thin varicose fibers ran parallel to the smooth muscle cells. In the 3-month old rats, a larger number of intensely staining SP-immunoreactive nerve fibres were found and in the circular muscle layer, thicker nerve strands were observed. In the 26-month old rats, the density and staining intensity of SP-immunopositive nerve fibres in the myenteric plexus was lower than in the 3-month-old rats. Similar changes in the SP-immunostained fibres in the internal anal sphincter were observed. Degenerative alterations in SP-containing fibres during aging appear to play a role in ano-rectal motility and sphincter control.

Circulating hyaluronan levels in the rodent: effects of age and diet

1995 ◽  
Vol 268 (4) ◽  
pp. C952-C957 ◽  
Author(s):  
J. Yannariello-Brown ◽  
S. H. Chapman ◽  
W. F. Ward ◽  
T. C. Pappas ◽  
P. H. Weigel
Keyword(s):  
Fish Meal ◽  
Caloric Intake ◽  
Protein Source ◽  
Male Rats ◽  
Semisynthetic Diet ◽  
Fischer 344 ◽  
Age Related ◽  
Old Rats ◽  
Ad Libitum ◽  
Age Related Changes

Circulating hyaluronan (HA) levels were investigated as a function of age and diet in Fischer 344 male rats. A biphasic pattern of age-related changes was observed in rats fed ad libitum a diet in which the protein source was soya/fish meal. HA levels in 3- to 6- and 22- to 29-mo-old rats were not statistically different. However, HA levels in 12- to 20-mo-old rats were 10-29% of the levels in younger or aged adults. HA levels were also measured in rats fed ad libitum a semisynthetic diet in which the protein source was hydrolyzed casein. Whereas the two colonies exhibited similar biphasic age-related changes, HA levels differed 4- to 20-fold at every age examined. Caloric restriction affected HA levels in 19-mo-old casein-fed rats; HA levels were 2.3 times higher than age-matched controls and were not statistically different from young or aged animals. Serum and plasma HA levels were identical in the same individuals at all ages tested. These data suggest that HA turnover and metabolism in the rat are affected by age, dietary composition, and caloric intake.

scholarly journals Age-related changes of neutrophil characteristics, potential of activation, DNA release and NET formation

2020 ◽  
Author(s):  
Moritz Krall ◽  
Lisa-Marie Mauracher ◽  
Johanna Roiss ◽  
Lena Hell ◽  
Anna S Ondracek ◽  
...  
Keyword(s):  
Age Groups ◽  
Membrane Receptors ◽  
Lower Amount ◽  
Older Individuals ◽  
Activation Markers ◽  
Disease States ◽  
Age Related ◽  
Release Assay ◽  
Dna Release ◽  
Age Related Changes

Abstract Background: Neutrophils are a heterogeneous population of leukocytes, which can be subdivided into high and low density neutrophils (HDNs/LDNs). They are known to fight intruders with different mechanisms, including the release of neutrophil extracellular traps (NETs), which have also been associated with thrombosis. Risks of infection and thrombosis increase with age. Differences in neutrophil subpopulations and functionality have been shown in various disease states, but investigations in healthy subjects and their dependence on age are lacking. The aim of this study was to investigate age-related changes in neutrophils regarding neutrophil subpopulations, their potential of activation, DNA release and NET formation.Methods: Neutrophil subpopulations (HDNs and LDNs) were isolated from 25 healthy individuals subdivided into 3 groups (<45 years, n=8; 45-54, n=9; >54, n=8). Neutrophil characteristics, potential of activation and the ability of NET formation was investigated using flow cytometry. Externalisation of DNA was detected by a DNA release assay.Results: HDN and LDN counts did not differ between age-groups. However, with increasing age we observed a shift in neutrophil subpopulations towards a lower amount of mature LDNs, characterized by their expression of membrane receptors CD62L and CD16. Upon stimulation, neutrophils of older individuals showed significantly higher release of DNA. HDNs of younger participants increased activation markers (CD66b and CD11b) to a higher extent compared to those of older individualsConclusion: Neutrophils and their ability of activation, DNA release and NET formation change with age and this might contribute to the higher risk of infection and thrombosis at advanced age. Furthermore, these results highlight the importance and necessity of age-matching in studies that focus on neutrophil characteristics.

scholarly journals Age-Related Changes in Sirtuin 7 Expression in Calorie-Restricted and Refed Rats

Gerontology ◽  
2015 ◽  
Vol 62 (3) ◽  
pp. 304-310 ◽  
Author(s):  
Agata Wronska ◽  
Aleksandra Lawniczak ◽  
Piotr M. Wierzbicki ◽  
Zbigniew Kmiec
Keyword(s):  
Gene Expression ◽  
Protein Expression ◽  
Calorie Restriction ◽  
Ribosome Biogenesis ◽  
Healthy Aging ◽  
Mrna Levels ◽  
Age Related ◽  
Mrna And Protein Expression ◽  
Old Rats ◽  
Age Related Changes

Background: Sirtuins (SIRT1-7) have been implicated to mediate the beneficial effects of calorie restriction for healthy aging. While the physiological functions of SIRT7 are still poorly understood, SIRT7 has recently been shown to affect ribosome biogenesis, mitochondrial gene expression, and hepatic lipid metabolism. Objective: To analyze the effects of age and short-term calorie restriction (SCR) and subsequent refeeding on SIRT7 expression in key metabolic tissues. Methods: Four- and 24-month-old male Wistar rats were subjected to 40% SCR for 30 days, followed by ad libitum feeding for 2 or 4 days. Liver, white adipose tissue (WAT), heart and skeletal muscle samples were analyzed by real-time PCR and Western blotting for SIRT7 mRNA and protein expression, respectively. Results: Aging had diverse effects on SIRT7 levels in lipogenic tissues: both the mRNA and protein levels increased in the retroperitoneal depot (rWAT), did not change in the epididymal depot (eWAT), and decreased in the subcutaneous depot (sWAT) and the liver of old as compared to young animals. In the heart, extensor digitorum longus muscle (EDL) and soleus muscle (SOL), Sirt7 gene but not protein expression was lower in old than in young control rats. SCR did not affect SIRT7 expression in WAT and the liver in both age groups. In the heart of young animals, SCR did not affect SIRT7 mRNA or protein level. In EDL, SIRT7 protein but not mRNA levels decreased after SCR and remained reduced upon refeeding. In SOL, both SIRT7 mRNA and protein expression were inhibited by refeeding. In old rats, cardiac Sirt7 expression increased after SCR and refeeding. In old rats' EDL and SOL muscles, SIRT7 protein expression was inhibited by refeeding. Conclusion: Age-related changes of SIRT7 gene expression in key organs of energy homeostasis are tissue dependent.

Longitudinal studies on human schistosomiasis

1988 ◽  
Vol 321 (1207) ◽  
pp. 495-511 ◽  
Keyword(s):  
Immune Responses ◽  
Acquired Resistance ◽  
Acquired Immunity ◽  
Contaminated Water ◽  
Older Individuals ◽  
Human Schistosomiasis ◽  
Slow Development ◽  
Age Related ◽  
Slow Decline ◽  
Age Related Changes

A major difficulty in understanding the epidemiology of human schistosomiasis has been to distinguish between acquired immunity and reduced exposure as possible reasons for an observed decline, in older individuals, of levels of superinlection or of reinfection after chemotherapy. A series of studies of Schistosoma mansoni infections in Kenya has been undertaken to approach this problem, by investigation of intensities of reinfection after treatment of individuals whose levels of contact with contaminated water is subsequently observed. Intensities of reinfection are highest among younger children, thereafter declining sharply. This decline can be attributed only in part to age-related changes in the duration and nature of exposure; there is also evidence for the development of an acquired resistance to reinfection that is dependent both on age and on previous experience of infection, and that may be immunologically mediated. Evidence has been obtained that the slow development of this acquired immunity with age may be associated with the early development and subsequent slow decline of inappropriate immune responses that ‘block' the effect of potentially protective responses. Implications of these findings for immunological intervention through vaccination are discussed.

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