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  3. By 1950, the results of attempts to relate brain processes to mental experience appeared rather discouraging. Such variations in

By 1950, the results of attempts to relate brain processes to mental experience appeared rather discouraging. Such variations in

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问题     By 1950, the results of attempts to relate brain processes to mental experience appeared rather discouraging. Such variations in size, shape, chemistry, conduction speed, excitation threshold, and the like as had been demonstrated in nerve cells remained negligible in significance for any possible correlation with the manifold dimensions of mental experience.
    Near the turn of the century, it had been suggested by Hering that different modes of sensation, such as pain, taste, and color, might be correlated with the discharge of specific kinds of nervous energy. However, subsequently developed methods of recording and analyzing nerve potentials failed to reveal any such qualitative diversity. It was possible to demonstrate by other methods refined structural differences among neuron types; however, proof was lacking that the quality of the impulse or its conduction was influenced by these differences, which seemed instead to influence the developmental patterning of the neural circuits. Although qualitative variance among nerve energies was never rigidly disproved, the doctrine was generally abandoned in favor of the opposing view, namely, that nerve impulses were essentially homogeneous in quality and were transmitted as "common currency" throughout the nervous system. According to his theory, it is not the quality of the sensory nerve impulses that determines the diverse conscious sensations they produce, but rather the different areas of the brain into which they discharge, and there is some evidence for this view. In one experiment, when an electric stimulus was applied to a given sensory field of the cerebral cortex of a conscious human subject, it produced a sensation of the appropriate modality for that particular locus, that is, a visual sensation from the visual cortex, an auditory sensation from the auditory cortex, and so on. Other experiments revealed slight variations in the size, number, arrangement, and interconnection of the nerve cells, but as far as psychoneural correlations were concerned, the obvious similarities of these sensory fields to each other seemed much more remarkable than any of the minute differences.
     However, cortical locus, in itself, turned out to have little explanatory value. Studies showed that sensations as diverse as those of red, black, green, and white, or touch, cold, warmth, movement, pain, cortical areas. What seemed to remain was some kind of differential patterning effects in the brain excitation., it is the difference in the central distribution of impulses that counts. In short, brain theory suggested a correlation between mental experience and the activity of relatively homogeneous nerve cell units conducting essentially homogeneous impulses through homogeneous cerebral tissue. To match the multiple dimensions of mental experience psychologists could only point to a limitless variation in the spatiotemporal patterning of nerve impulses.
From the passage we know that the nerve impulses in human beings ______.
选项 A、are lack of differentiation in quality
B、are similar in size, number, and arrangements
C、reveal qualitative diversity
D、spasmodically pass through the nervous system
答案A
解析 语义理解题。问人类的神经脉冲的性质。文章说：“…神经脉冲从本质上来讲在性质上都是一样的，它作为一般流通被传输到神经系统”(...that nerve impulses were essentially homogeneous in quality and were transmitted as common currency, throughout the nervous system)，所以人类的神经脉冲缺乏差异性，并持续不断地通过神经系统。
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