TEMPORAL-MODULATION TRANSFER-FUNCTIONS FOR AM AND FM STIMULI IN CAT AUDITORY-CORTEX - EFFECTS OF CARRIER TYPE, MODULATING WAVE-FORM AND INTENSITY
TEMPORAL-MODULATION TRANSFER-FUNCTIONS FOR AM AND FM STIMULI IN CAT AUDITORY-CORTEX - EFFECTS OF CARRIER TYPE, MODULATING WAVE-FORM AND INTENSITY
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DOI：
10.1016/0378-5955(94)90175-9
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发表时间：
1994-04-01
期刊：
影响因子：
2.8
通讯作者：
EGGERMONT, JJ
中科院分区：
文献类型：
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作者：
EGGERMONT, JJ
对于从 28 只猫的初级听觉皮层记录的 167 个单个单元，我们发现调幅 (AM) 声音的调制频率 (MF) 的调谐在很大程度上取决于载波类型。 In general AM noise-bursts and click-trains produce good tuning to MFs with repetition rates around 8-10 Hz.音调载波的幅度或频率调制很大程度上产生了低通时间调制传递函数 (tMTF)，最佳调制频率 (BMF) 约为 4 Hz。噪声载波的各个 BMF 范围为 3-26 Hz，而对于音调载波，它们大多低于 6 Hz，很少高于 10 Hz。宽带刺激的调谐锐度随着调制占空比的增加而降低；它对于点击次数最为明显，对于指数正弦 AM 次之，对于正弦 AM 最广泛。相比之下，音调载体的情况正好相反。正弦调制具有更好的调制跟随性，并且很可能完全是由于更强的起始响应。将调制深度降低到 100% 以下表明瞬态开始和周期性反弹的影响越来越大，但是深度在 50-100% 之间的平均 tMTF 相似。 The optimal intensity level for noise carriers was usually higher than for tone carriers.总体而言，无论载波类型和调制波形如何，皮质神经元的调制敏感性都在音乐、语音和其他复杂声音中发现的调制频率范围内。
For 167 single units, recorded from primary auditory cortex in 28 cats, we show that tuning to the modulation frequency (MF) of amplitude-modulated (AM) sound is strongly dependent on carrier type. In general AM noise-bursts and click-trains produce good tuning to MFs with repetition rates around 8-10 Hz. Amplitude- or frequency-modulation of tone-carriers resulted largely in low-pass temporal modulation transfer functions (tMTFs) with a best modulation frequency (BMF) around 4 Hz. Individual BMFs for noise carriers ranged from 3-26 Hz, whereas for tone carriers they were mostly below 6 Hz and rarely above 10 Hz. The sharpness of tuning for broad-band stimuli decreased with increasing duty-cycle of the modulation; it was most pronounced for clicks, next best for exponential sine-AM and broadest for sinusoidal AM. In contrast the reverse was found for tone carriers; the better modulation following was found for sinusoidal modulation and was most likely entirely due to a stronger onset response. Decreasing the modulation depth below 100% showed an increasing influence of onset transients and periodic rebounds, however, the average tMTFs for depths between 50-100% are similar. The optimal intensity level for noise carriers was usually higher than for tone carriers. Overall the modulation-sensitivity of cortical neurons regardless of carrier type and modulating waveform was in the range of modulation frequencies found in music, speech and other complex sounds.