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Decreased contrast sensitivity of visual cortical cells to visual stimuli accompanies a reduction of intracortical inhibition in old cats 被引量:2
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作者 周俊 施夏明 +2 位作者 彭青松 化国鹏 华田苗 《Zoological Research》 CAS CSCD 北大核心 2011年第5期533-539,共7页
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
关键词 Contrast sensitivity V1 neurons old cats Young adult cats
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Effects of urethane on the response properties of visual cortical neurons in young adult and old cats 被引量:3
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作者 彭青松 周俊 +2 位作者 施夏明 化国鹏 华田苗 《Zoological Research》 CAS CSCD 北大核心 2011年第3期337-342,共6页
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
关键词 URETHANE Anesthesia effects Neuronal response properties Primary visual cortex Young adult cats old cats
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Decline of selectivity of V1 neurons to visual stimulus spatial frequencies in old cats
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作者 化国鹏 施夏明 +2 位作者 周俊 彭青松 华田苗 《Neuroscience Bulletin》 SCIE CAS CSCD 2011年第1期9-14,共6页
Objective To examine whether the selectivity of visual cortical neurons to stimulus spatial frequencies would be affected by aging in cats.Methods In vivo extracellular single-unit recording techniques were employed t... Objective To examine whether the selectivity of visual cortical neurons to stimulus spatial frequencies would be affected by aging in cats.Methods In vivo extracellular single-unit recording techniques were employed to record the tuning responses of V1 neurons to different stimulus spatial frequencies in old and young adult cats.Results Statistical analysis showed that the mean optimal spatial frequency of grating stimuli that evoked the maximal response of V1 neurons in old cats was significantly lower than that in young adult cats.Furthermore,the mean high cut-off spatial frequency of grating stimuli that evoked the half amplitude of the maximal response of V1 neurons in old cats was also significantly lower than that in young adult cats.Conclusion These results are consistent with those reported in the V1 of old monkeys,suggesting that the age-related decline in the selectivity of visual cortical cells to spatial frequency could be generalized to all mammalian species and might contribute to visual acuity reduction in senescent individuals. 展开更多
关键词 spatial frequency selectivity functional decline V1 neurons old cats
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