PROGRESSIVE IMPROVEMENT IN DISCRIMINATIVE ABILITIES IN ADULT OWL MONKEYS PERFORMING A TACTILE FREQUENCY DISCRIMINATION TASK
PROGRESSIVE IMPROVEMENT IN DISCRIMINATIVE ABILITIES IN ADULT OWL MONKEYS PERFORMING A TACTILE FREQUENCY DISCRIMINATION TASK
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DOI：
10.1152/jn.1992.67.5.1015
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发表时间：
1992-05-01
影响因子：
2.5
通讯作者：
MERZENICH, MM
中科院分区：
文献类型：
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作者：
RECANZONE, GH;JENKINS, WM;MERZENICH, MM
1.成年猫头鹰猴被训练来检测顺序施加触觉刺激的频率差异，触觉刺激呈现在单个手指的无毛皮肤上的恒定的、受限的位置。在为期3至20周的训练期内，每天进行心理物理性能功能和阈值测定。相对于20 Hz的标准，训练后的手指的频率从6 Hz到8 Hz逐渐降低到2 Hz到3 Hz。这些阈值与猕猴和人类通过使用两种选择的强制选择程序确定的阈值相似。七只被研究的猴子中有六只在训练中表现出不断进步的改善。在训练初期，所有频率的性能都以大约相同的速度提高。在训练期的后期，频率比比较频率大得多的性能比频率更类似于比较频率的性能提高得更快。这导致心理测量函数在阈值附近的斜率增加。在一只猴子中，没有记录到明显的后成分改善。使用信号检测理论进行的性能分析显示，对于阈值以上的所有频率，da'的测量逐渐增加。当刺激施加在相邻的手指上时，也记录了性能的一些改善，该手指在整个训练过程中间隔训练2或3次。然而，这些数字上的阈值总是大于训练数字上的阈值。这些发现表明，在中枢躯体感觉神经系统的躯体位置限制区域，这种训练产生了局部变化。它的结论是，这种训练导致了一个真正的渐进式改善，具体到训练皮肤的时间敏锐度。最初的快速改善很可能是由于改善的“战略”或“认知”方面的任务，而更渐进的改善，在整个培训期间记录的性能最有可能是由于somatotopically本地化的变化，在神经表征的行为相关的刺激。
1. Adult owl monkeys were trained to detect a difference in the frequency of sequentially applied tactile stimuli presented to a constant, restricted location on the glabrous skin of a single finger. Psychophysical performance functions and thresholds were determined on daily sessions over a 3- to 20-wk-long training period.2. Thresholds for the trained digit progressively decreased from a 6- to 8-Hz difference to a 2- to 3-Hz difference relative to a 20-Hz standard. These thresholds were similar to those described for macaques and humans determined by the use of a two-alternative forced-choice procedure.3. Six of the seven studied monkeys showed a continuously progressive improvement in performance with training. Early in the training period, the performance improved at about the same rate for all frequencies. Later in the training period, the performance for frequencies much greater than the comparison frequency improved sooner than did the performances for frequencies more similar to the comparison frequency. This resulted in an increase of the slope of the psychometric function near threshold. In a single monkey, no clear later-component improvements were recorded.4. Analyses of performances using the theory of signal detection revealed a progressive increase in the measure of da' for all frequencies above threshold.5. Some improvements in performance were also recorded when stimuli were applied on an adjacent digit, which was trained for 2 or 3 sessions spaced throughout the course of training. However, thresholds on these digits were always greater than those on the trained digit. These findings suggest that there are local changes generated by this training at somatotopically restricted regions of the central somatosensory nervous system.6. It is concluded that this training resulted in a genuine progressive improvement in temporal acuity specific to the trained skin. The initial rapid improvement was likely due to an improvement in the "strategy" or "cognitive" aspects of the task, whereas more gradual improvements in performance recorded throughout the training period were most probably due to somatotopically localized changes in the neural representations of the behaviorally relevant stimulus.