Meddis Ray, O'Mard Lowel P
Centre for the Neural Basis of Hearing at Essex, Department of Psychology, University of Essex, Colchester C04 3SQ, United Kingdom.
J Acoust Soc Am. 2005 Jun;117(6):3787-98. doi: 10.1121/1.1893426.
A computer model of the auditory periphery is used to study the involvement of auditory-nerve (AN) adaptation in forward-masking effects. An existing model is shown to simulate published AN recovery functions both qualitatively and quantitatively after appropriate parameter adjustments. It also simulates published data showing only small threshold shifts when a psychophysical forward-masking paradigm is applied to AN responses. The model is extended to simulate a simple but physiologically plausible mechanism for making threshold decisions based on coincidental firing of a number of AN fibers. When this is used, much larger threshold shifts are observed of a size consistent with published psychophysical observations. The problem of how stimulus-driven firing can be distinguished from spontaneous activity near threshold is also addressed by the same decision mechanism. Overall, the modeling results suggest that poststimulatory reductions in AN activity can make a substantial contribution to the raised thresholds observed in many psychophysical studies of forward masking.
一个听觉外周的计算机模型被用于研究听觉神经（AN）适应在前向掩蔽效应中的作用。结果表明，在进行适当的参数调整后，一个现有的模型能够定性和定量地模拟已发表的AN恢复函数。当将心理物理学前向掩蔽范式应用于AN反应时，该模型还能模拟已发表的数据，这些数据显示阈值变化很小。该模型被扩展以模拟一种基于多个AN纤维同时放电进行阈值决策的简单但符合生理原理的机制。当使用这种机制时，观察到的阈值变化要大得多，其大小与已发表的心理物理学观察结果一致。同样的决策机制也解决了如何将刺激驱动的放电与阈值附近的自发活动区分开来的问题。总体而言，建模结果表明，刺激后AN活动减少可能对许多前向掩蔽心理物理学研究中观察到的阈值升高有很大贡献。
