SENSITIVITY OF NEURONS IN CAT PRIMARY AUDITORY-CORTEX TO TONES AND FREQUENCY-MODULATED STIMULI .1. EFFECTS OF VARIATION OF STIMULUS PARAMETERS
SENSITIVITY OF NEURONS IN CAT PRIMARY AUDITORY-CORTEX TO TONES AND FREQUENCY-MODULATED STIMULI .1. EFFECTS OF VARIATION OF STIMULUS PARAMETERS
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DOI：
10.1016/0378-5955(92)90080-7
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发表时间：
1992-11-01
期刊：
影响因子：
2.8
通讯作者：
IRVINE, DRF
中科院分区：
文献类型：
--
作者：
HEIL, P;RAJAN, R;IRVINE, DRF
分析了巴比妥酸麻醉猫初级听觉皮层（AI）对音调和调频（FM）音调刺激的多单元反应，确定了特征频率（CF）、调谐锐度、最小阈值和尖峰计数-强度函数的动态范围。最小阈值与动态范围呈正相关。不同线性频率变化率（RCF）的单向调频扫描穿过兴奋性频率响应区（FRAs）时，其响应函数呈现出不同的形状。最常见的是对快速rcf （> 1000 kHz/s）的偏好。最佳RCF与调谐的清晰度没有相关性。方向偏好和敏感性通过随RCF变化的DS指数来量化。大约三分之二的多单元反应显示出向下扫的偏好。方向灵敏度与CF无关，与最佳RCF无关。对不同RCF的单向调频扫描的相位响应潜伏期的测量表明，给定多单元在其有效RCF范围内的放电是在相同的瞬时频率（有效F(i)）启动的，与RCF无关。有效F(i)s落在给定多单元的兴奋性FRA范围内。的关系有效F (i) s CF表明反应诱发只有当信号调制的频率对CF而不是当调制远离它,,反应开始前调制达到CF。调制的范围和深度的变化只有轻微,如果有的话,影响RCF响应特性、调频定向灵敏度,F (i)和有效的年代,只要开始和结束频率FM扫跌多部件外的联邦铁路局。刺激强度也仅对RCF反应特征和DS有中等影响。然而，有效的F(i)s以系统的方式受到影响：随着强度的增加，向上和向下扫描的有效F(i)s分别减少和增加。因此，对于更高强度的调频响应是在信号中较早出现的瞬时频率上启动的。将实验结果与皮层和皮层下听觉神经元的音调和调频敏感性进行了比较，并讨论了调频率和方向敏感性的机制。人工智能中这些神经元属性的地形表征在同伴报告中报道。
In the primary auditory cortex (AI) of barbiturate-anesthetized cats multi-unit responses to tones and to frequency-modulated (FM) tonal stimuli were analyzed, Characteristic frequency (CF), sharpness of tuning, minimum threshold, and dynamic range of spike count - intensity functions were determined. Minimum threshold and dynamic range were positively correlated. The response functions to unidirectional FM sweeps of varying linear rate of change of frequency (RCF) that traversed the excitatory frequency response areas (FRAs) displayed a variety of shapes. Preferences for fast RCFs ( > 1000 kHz/s) were most common. Best RCF was not correlated with measures of sharpness of tuning. Directional preference and sensitivity were quantified by a DS index which varied with RCF. About two-thirds of the multi-unit responses showed a preference for downward sweeps. Directional sensitivity was independent of CF and independent of best RCF. Measurements of latencies of phasic responses to unidirectional FM sweeps of different RCF demonstrated that the discharges of a given multi-unit over its effective RCF range were initiated at the same instantaneous frequency (effective F(i)), independent of RCF. Effective F(i)s fell within the excitatory FRA of a given multi-unit. The relationships of effective F(i)s to CF show that responses were evoked only when the frequency of the signal was modulated towards CF and not when modulated away from it, and that responses were initiated before the modulation reached CF. Changes in the range and depth of modulation had only minor, if any, effects on RCF response characteristics, FM directional sensitivity, and effective F(i)s, as long as the beginning and ending frequencies of FM sweeps fell outside a multi-unit's FRA. Stimulus intensity also had only moderate effects on RCF response characteristics and DS. However, effective F(i)s were influenced in systematic fashions: with increases in intensity, effective F(i)s to upward and downward sweeps decreased and increased, respectively. Thus, for higher intensities FM responses were initiated at instantaneous frequencies occuring earlier in the signal. The results are compared with previous data on tone and FM sensitivity of auditory neurons in cortical and subcortical structures, and mechanisms of FM rate and directional sensitivity are discussed. The topographic representations of these neuronal properties in AI are reported in the companion report.