Psychophysical experiments on human and animal subjects have proven that aged individuals show significantly reduced visual contrast sensitivity compared with young adults.To uncover the possible neural mechanisms,we ...Psychophysical experiments on human and animal subjects have proven that aged individuals show significantly reduced visual contrast sensitivity compared with young adults.To uncover the possible neural mechanisms,we used extracellular single-unit recording techniques to examine the response of V1（primary visual cortex） neurons as a function of visual stimulus contrast in both old and young adult cats（Felis catus）.The mean contrast sensitivity of V1 neurons to visual stimuli in old cats decreased significantly relative to young adult cats,consistent with findings reported in old primates.These results indicate that aging can affect contrast sensitivity of visual cortical cells in both primate and non-primate mammalian animals,and might contribute to the reduction of perceptual visual contrast sensitivity in aged individuals.Further,V1 cells of old cats exhibited increased responsiveness,decreased signal-to-noise ratio,and enlarged receptive field（RF） size compared with that of young adult cats,which indicated that decreased contrast sensitivity of V1 neurons accompanied a reduction of intracortical inhibition during senescence.展开更多
Previous studies have shown that visual cortical neurons in old mammals exhibit higher spontaneous activity,higher responsiveness to visual stimuli,and lower selectivity for stimulus orientations and motion directions...Previous studies have shown that visual cortical neurons in old mammals exhibit higher spontaneous activity,higher responsiveness to visual stimuli,and lower selectivity for stimulus orientations and motion directions than did neurons in young adult counterparts.However,whether the responsive difference in cortical neurons between young and old animals resulted from different effects induced by anesthetics has remained unclear.To clarify this issue,we recorded the response properties of individual neurons in the primary visual cortex of old and young adult cats while systematically varying the anesthesia level of urethane,a widely used anesthetic in physiology experiments.Our results showed that cumulatively administrating 50 mg and 100 mg of urethane upon the minimal level of urethane required to anesthetize an old or young adult cat did not significantly alter the degree of neuronal response selectivity for stimulus orientations and motion directions nor significantly change the visually-driven response and spontaneous activity of neurons in old and young adult cats.Cumulatively administrating 150 mg of urethane decreased neuronal responsiveness similarly in both age groups.Therefore,urethane appears to exert similar effects on neuronal response properties of old and young adult animals.展开更多
Perceptual learning of orientation discrimination was investigated using cats. Two adult cats （Cat 1 and 2） were trained to monocularly discriminate between two static striped sinusoidal grates with 30° orienta...Perceptual learning of orientation discrimination was investigated using cats. Two adult cats （Cat 1 and 2） were trained to monocularly discriminate between two static striped sinusoidal grates with 30° orientation difference. After greater than 80% correct performance was reached, cats were then required to monocularly perform a discrimination between two grates with consecutively shifting orientation difference（2°, 4°, 6°, 8°, 10°, 12°, 16°, 20°, 24°, 30°） . The staircase method （two correct-down and one error-up） was applied throughout the training to track the threshold of orientation difference that cats could detect. The performance of detecting grates with varied orientation difference was measured respectively for beth trained and untrained eyes before and after training. Our results showed that the learning effect of discrimination for grates with a fixed orientation difference transferred completely from the trained eye to the untrained eye, whereas the inter-eye transfer for detecting °ates with gradually reducing orientation difference was almost nonegrates. The two opposite learning effects in the same subject strongly suggest that different information processing mechanisms might mediate the learning processes.展开更多
Background: Periodontal infections are the most common disease of cats and dogs. About 70% - 80% of them suffer from these infections during their lifetime. These infections occur in two forms, gingivitis and periodon...Background: Periodontal infections are the most common disease of cats and dogs. About 70% - 80% of them suffer from these infections during their lifetime. These infections occur in two forms, gingivitis and periodontitis. Gingivitis is a reversible inflammation of the gingiva which can be cured. As with humans, the harmful bacteria can cause infections also in organs such as the heart, liver and kidneys. Besides veterinary treatment, also the owner’s everyday care is essential. Objective: The aim of the study was to develop and clinically test easy home care probiotic product for cats’ and dogs’ oral health. Methods: Nine cats and thirteen dogs were given a combination of selected bacteria Streptococcus thermophilus SP4, Lactobacillus plantarum 14D and Lactobacillus rhamnosus SP1 (Petguide powder) in powder form daily for four weeks on top of the dry feed. Microbiological samples were taken before and after the intervention from each dog and cat. The samples were analyzed with flow cytometric analysis using Porphyromonas gingivalis and Fusobacterium sp. as indicators for oral health. Results: The home care treatment with these specific, live probiotic bacteria was shown to prevent the growth of infectious bacteria within four weeks. Petguide probiotic powder reduced the relative abundance of infectious microbes significantly (p = 0.005) in cats and dogs. Conclusion: The results suggest that the probiotic product with three live strains of probiotic bacteria prevents the growth of infectious bacterial species that are known to cause infections in pets’ mouths. Therefore, this probiotic combination could be used to improve the oral health of pets and increase their quality of life.展开更多
基金Supported by National Natural Science Foundation of China(31171082)Natural Science Foundation of Anhui Province(070413138)the Key Research Foundation of Anhui Province Education Department(KJ2009A167)
文摘Psychophysical experiments on human and animal subjects have proven that aged individuals show significantly reduced visual contrast sensitivity compared with young adults.To uncover the possible neural mechanisms,we used extracellular single-unit recording techniques to examine the response of V1（primary visual cortex） neurons as a function of visual stimulus contrast in both old and young adult cats（Felis catus）.The mean contrast sensitivity of V1 neurons to visual stimuli in old cats decreased significantly relative to young adult cats,consistent with findings reported in old primates.These results indicate that aging can affect contrast sensitivity of visual cortical cells in both primate and non-primate mammalian animals,and might contribute to the reduction of perceptual visual contrast sensitivity in aged individuals.Further,V1 cells of old cats exhibited increased responsiveness,decreased signal-to-noise ratio,and enlarged receptive field（RF） size compared with that of young adult cats,which indicated that decreased contrast sensitivity of V1 neurons accompanied a reduction of intracortical inhibition during senescence.
基金Supported by Natural Science Foundation of Anhui Province (070413138)the Key Research Foundation of Anhui Province Education Department (KJ2009A167)
文摘Previous studies have shown that visual cortical neurons in old mammals exhibit higher spontaneous activity,higher responsiveness to visual stimuli,and lower selectivity for stimulus orientations and motion directions than did neurons in young adult counterparts.However,whether the responsive difference in cortical neurons between young and old animals resulted from different effects induced by anesthetics has remained unclear.To clarify this issue,we recorded the response properties of individual neurons in the primary visual cortex of old and young adult cats while systematically varying the anesthesia level of urethane,a widely used anesthetic in physiology experiments.Our results showed that cumulatively administrating 50 mg and 100 mg of urethane upon the minimal level of urethane required to anesthetize an old or young adult cat did not significantly alter the degree of neuronal response selectivity for stimulus orientations and motion directions nor significantly change the visually-driven response and spontaneous activity of neurons in old and young adult cats.Cumulatively administrating 150 mg of urethane decreased neuronal responsiveness similarly in both age groups.Therefore,urethane appears to exert similar effects on neuronal response properties of old and young adult animals.
基金This work was supported by the Foundationfor Key Laboratories of Anhui Province andthe Initiating Fundfor Ph.D.in AnhuiNormal University
文摘Perceptual learning of orientation discrimination was investigated using cats. Two adult cats （Cat 1 and 2） were trained to monocularly discriminate between two static striped sinusoidal grates with 30° orientation difference. After greater than 80% correct performance was reached, cats were then required to monocularly perform a discrimination between two grates with consecutively shifting orientation difference（2°, 4°, 6°, 8°, 10°, 12°, 16°, 20°, 24°, 30°） . The staircase method （two correct-down and one error-up） was applied throughout the training to track the threshold of orientation difference that cats could detect. The performance of detecting grates with varied orientation difference was measured respectively for beth trained and untrained eyes before and after training. Our results showed that the learning effect of discrimination for grates with a fixed orientation difference transferred completely from the trained eye to the untrained eye, whereas the inter-eye transfer for detecting °ates with gradually reducing orientation difference was almost nonegrates. The two opposite learning effects in the same subject strongly suggest that different information processing mechanisms might mediate the learning processes.
文摘Background: Periodontal infections are the most common disease of cats and dogs. About 70% - 80% of them suffer from these infections during their lifetime. These infections occur in two forms, gingivitis and periodontitis. Gingivitis is a reversible inflammation of the gingiva which can be cured. As with humans, the harmful bacteria can cause infections also in organs such as the heart, liver and kidneys. Besides veterinary treatment, also the owner’s everyday care is essential. Objective: The aim of the study was to develop and clinically test easy home care probiotic product for cats’ and dogs’ oral health. Methods: Nine cats and thirteen dogs were given a combination of selected bacteria Streptococcus thermophilus SP4, Lactobacillus plantarum 14D and Lactobacillus rhamnosus SP1 (Petguide powder) in powder form daily for four weeks on top of the dry feed. Microbiological samples were taken before and after the intervention from each dog and cat. The samples were analyzed with flow cytometric analysis using Porphyromonas gingivalis and Fusobacterium sp. as indicators for oral health. Results: The home care treatment with these specific, live probiotic bacteria was shown to prevent the growth of infectious bacteria within four weeks. Petguide probiotic powder reduced the relative abundance of infectious microbes significantly (p = 0.005) in cats and dogs. Conclusion: The results suggest that the probiotic product with three live strains of probiotic bacteria prevents the growth of infectious bacterial species that are known to cause infections in pets’ mouths. Therefore, this probiotic combination could be used to improve the oral health of pets and increase their quality of life.
