PSYCHOPHYSICAL STUDY OF VIBROTACTILE TEMPORAL SUMMATION

该项目的长期目标是通过对振动触觉时间求和的实验研究来扩展我们对感官系统时间特性的认识。通过测量心理物理阈值来检测呈现给手部无毛皮肤的正弦刺激，时间整合的基本机制应该揭示自己。目的是通过实验分离两种可能的基本机制，可能是总和和神经整合负责所有感觉系统的时间总和，并确定它们在振动作用下运作的条件。当外部背景噪声的水平和频谱特征被控制时，通过测量检测单脉冲和多脉冲刺激的心理物理阈值，将有可能检验这样一个假设，即感觉系统中的汇总可能需要足够水平的内部或外部噪声，以便在系统的神经反应中引入大量的可变性，以重复呈现相同的刺激。通过测量检测被噪声分离的多个脉冲的阈值，这些噪声被设计用来破坏可能在刺激终止后发生的神经活动的持续性，这将有可能检验神经持续性对神经整合机制的运作至关重要的假设。通过使用选择性适应的方法，将有可能测量20至540赫兹刺激频率范围内的时间总和。研究结果将检验Zwislocki（1960）的假设，该假设是为了解释听觉中的时间累加，即正弦刺激中的单个周期可以作为神经整合中的单个刺激事件。通过在正弦信号中关联周期，可以作为神经整合中的单个刺激事件。通过将时间求和、时间间隙检测和前向掩蔽的测量相关联，可以确定当需要进行时间求和时，神经持续性是否降低了时间敏锐度并破坏了持久性；当需要进行时间求和时，神经持续性是否降低了时间敏锐度并破坏了掩蔽刺激终止后呈现的信号的可检测性。

The broad long-term goal of the project is to extend our knowledge of the temporal properties of sensory systems through an experimental study of vibrotactile temporal summation. By measuring psychophysical thresholds for detecting sinusoidal stimuli presented to the glabrous skin of the hand, the basic mechanisms of temporal integration should reveal themselves. The objective is to experimentally isolate the two possible fundamental mechanisms, probably summation and neural integration responsible for temporal summation in all sensory systems, and to define the conditions under which they operate in vibrotaction. By measuring psychophysical thresholds for detecting single and multiple-pulse stimuli when the level of and spectral characteristics of external background noise are manipulated it will be possible to test the hypothesis that probably summation in a sensory system requires a sufficient level of either internal or external noise so as to introduce a substantial amount of variability in the neural responses of the system, to repeated presentation of the same stimulus. By measuring thresholds for detecting multiple pulses separated by noise designed to disrupt the persistence of neural activity that could occur after termination of a stimulus, it will be possible to test the hypothesis that neural persistence is essential for the operation of the mechanism of neural integration. Through the use of a method of selective adaptation it will be possible to measure temporal summation over a range of stimulus frequencies from 20 to 540 Hz. The results will test Zwislocki's (1960) hypothesis, proposed to account for temporal summation in hearing, that individual cycles in a sinusoidal stimulus can serve as individual stimulus events in neural integration. By correlating cycles in a sinusoidal can serve as individual stimulus events in neural integration. By correlating measures of temporal summation, temporal gap detection and forward masking it will be possible to determine whether neural persistence, when necessary for temporal summation, reduces temporal acuity and disrupts the persistence, when necessary for temporal summation, reduces temporal acuity and disrupts the detectability of a signal presented after the termination of a masking stimulus.