AGING AND THE NERVOUS SYSTEM

这个项目的总体目标是研究行为， 在神经系统正常老化过程中发生的解剖学和生物化学变化 哺乳动物的神经系统，以及老化的神经系统的潜力，以补偿 对于这些变化。 为了实现这些目标，正在建立一些系统。 考察 在听觉系统中，年龄对大鼠的听觉能力的影响 获得和保持听觉辨别力正在研究中，这种能力 与耳蜗的形态年龄变化相关， 核和螺旋神经节。 形态学变化包括检查 受体细胞的丧失，神经元之间突触的变化， 色素的积累。 更重要的是，听觉神经元的能力 大脑皮层在不同年龄对传入神经阻滞的反应正在被研究， 确定胼胝体输入的损失是否会导致 从丘脑进入皮层的传入神经 在嗅觉系统中 受体细胞、神经元及其突触的形态学改变 随着老鼠年龄的增长， 这些研究还将表明， 衰老的神经系统仍然具有可塑性， 目前正在进一步研究齿状回中的轴突。 神经元老化的一个可能的重要因素是神经元的状态。 微血管网络，这是生物化学和 从解剖学上讲 正在对核武器进行更多的生物化学研究， 染色质，与年龄的影响正在评估，通过确定 染色质对细菌核酸酶切割敏感性。

The general objective of this program project is to examine behavioral, anatomical and biochemical changes that occur during normal aging of the nervous system of mammals, and the potential of the aging nervous system to compensate for these changes. To accomplish these goals, a number of systems are being examined. In the auditory system the effect of age on the ability of rats to acquire and maintain auditory discrimination are being studied, and this ability is being correlated with morphological age changes in the cochleas, cochlear nuclei and spiral ganglion. The morphological changes include examination of the loss of receptor cells, changes in synapses between neurons, and accumulation of pigment. More centrally, the ability of neurons in the auditory cortex to respond to deafferentation at varying ages are being examined to determine if loss of the callosal input results in compensatory growth of afferents entering the cortex from the thalamus. In the olfactory system changes in the receptor cells, the morphology of neurons and their synaptic input are being studied as rats age. These studies will also indicate if the aging nervous system still exhibits plasticity, and collateral sprouting of axons is being further studied in the dentate gyrus. A possible important factor in the aging of neurons is the state of the microvascular network, and this is being examined both biochemically and anatomically. Additional biochemical studies are being carried out on nuclear chromatin, with which the effects of age are being assessed by determining the susceptibility of chromatin to cleavage by bacterial nuclease.