Time course of forward masking tuning curves in cat primary auditory cortex
Time course of forward masking tuning curves in cat primary auditory cortex
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DOI：
10.1152/jn.1997.77.2.923
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发表时间：
1997-02-01
影响因子：
2.5
通讯作者：
Schreiner, CE
中科院分区：
文献类型：
--
作者：
Brosch, M;Schreiner, CE
在麻醉猫的初级听觉皮层研究了非同时双音相互作用。本文研究了纯音短脉冲（掩蔽音）对固定纯音短脉冲（探测音）诱发活动的后刺激效应。从掩蔽开始到探测开始的时间间隔（刺激开始时间）、掩蔽频率和强度是参数变化的。对于所有的53个单单位和58个多单位集群，神经活动的探测信号被抑制，促进，和/或延迟由一组有限的掩蔽刺激。刺激范围，从该探针的前向抑制诱导通常是集中在神经元的兴奋性感受野的大小，并有大约。这种“掩蔽调谐曲线”通常是V形的，即，抑制掩蔽刺激的频率范围随着掩蔽强度的增加而增加。前向抑制在掩蔽和探针之间的最短刺激起始时间处诱导。随着刺激起始时间的延长，抑制掩蔽的频率范围逐渐变小。从正向抑制恢复发生在第一次在较低和较高的频率边界的掩蔽调谐曲线，并持续最长的频率接近神经元的特征频率。前向抑制的最大持续时间测量为观察到探针响应减少的最长时间。它是在53-430毫秒的范围内，平均值为143 +/- 71（SD）ms。数量，持续时间和类型的前向抑制弱，但显着相关的“静态”的神经感受野特性，如特征频率，带宽和潜伏期。对于大多数神经元，最小抑制掩蔽强度随着刺激起始时间的延长而增加。在大多数情况下，最高的掩蔽强度诱导最长的前向抑制。然而，一个显着数量的神经元，表现出最长的抑制期后，掩蔽剂的中间强度。结果表明，皮层细胞的兴奋性活动的反应能力取决于时间的刺激上下文。当连续刺激的光谱内容不同时，神经元可以遵循更高的刺激序列重复率。皮层细胞感受野内以及不同细胞对时间声音序列的不同敏感性可能有助于对时间结构刺激（如语音和动物发声）的神经处理。
Nonsimultaneous two-tone interactions were studied in the primary auditory cortex of anesthetized cats. Poststimulatory effects of pure tone bursts (masker) on the evoked activity of a fixed tone burst (probe) were investigated. The temporal interval from masker onset to probe onset (stimulus onset asynchrony), masker frequency, and intensity were parametrically varied. For all of the 53 single units and 58 multiple-unit clusters, the neural activity of the probe signal was either inhibited, facilitated, and/or delayed by a limited set of masker stimuli. The stimulus range from which forward inhibition of the probe was induced typically was centered at and had approximately the size of the neuron's excitatory receptive field. This ''masking tuning curve'' was usually V shaped, i.e., the frequency range of inhibiting masker stimuli increased with the masker intensity. Forward inhibition was induced at the shortest stimulus onset asynchrony between masker and probe. With longer stimulus onset asynchronies, the frequency range of inhibiting maskers gradually became smaller. Recovery from forward inhibition occurred first at the lower- and higher-frequency borders of the masking tuning curve and lasted the longest for frequencies close to the neuron's characteristic frequency. The maximal duration of forward inhibition was measured as the longest period over which reduction of probe responses was observed. It was in the range of 53-430 ms, with an average of 143 +/- 71 (SD) ms. Amount, duration and type of forward inhibition were weakly but significantly correlated with ''static'' neural receptive field properties like characteristic frequency, bandwidth, and latency. For the majority of neurons, the minimal inhibitory masker intensity increased when the stimulus onset asynchrony became longer. In most cases the highest masker intensities induced the longest forward inhibition. A significant number of neurons, however, exhibited longest periods of inhibition after maskers of intermediate intensity. The results show that the ability of cortical cells to respond with an excitatory activity depends on the temporal stimulus context. Neurons can follow higher repetition rates of stimulus sequences when successive stimuli differ in their spectral content. The differential sensitivity to temporal sound sequences within the receptive field of cortical cells as well as across different cells could contribute to the neural processing of temporally structured stimuli like speech and animal vocalizations.