Schulze H, Langner G
Leibniz Institute for Neurobiology, Magdeburg, Germany.
J Comp Physiol A. 1999 Dec;185(6):493-508. doi: 10.1007/s003590050410.
Auditory neurons typically respond to a restricted range of frequencies and amplitudes of pure tone stimuli. These findings have led to the concept of the classical frequency receptive field. Over the last few years evidence has accumulated that stimuli outside the frequency and amplitude boundaries of a neuron's receptive field can influence responses to stimuli inside the classical receptive field. We could recently show that sinusoidally amplitude-modulated pure tones could excite cortical neurons although all of their spectral components were above the spectral range of pure tones effective to excite the neuron. This result demonstrated that neurons in the auditory cortex integrate over spectral ranges that are much wider than is evident from responses to pure tones. Here, using sinusoidally amplitude-modulated pure tone stimuli we determine electrophysiologically the high-frequency boundaries of the spectral integration capabilities of auditory cortical neurons in anaesthetized Mongolian gerbils under normal conditions and under the influence of the microiontophoretically applied GABAA-receptor antagonist bicuculline. Our results demonstrate that some auditory cortical neurons integrate over the gerbil's entire audible spectrum. Therefore, the classical excitatory frequency receptive field of an auditory cortical neuron, as determined with pure tone stimuli, cannot provide a satisfactory description of its spectral integrative properties.
听觉神经元通常对纯音刺激的有限频率范围和振幅做出反应。这些发现引出了经典频率感受野的概念。在过去几年中，有证据表明，神经元感受野频率和振幅边界之外的刺激会影响对经典感受野内刺激的反应。我们最近发现，正弦调幅纯音可以激发皮层神经元，尽管其所有频谱成分都高于有效激发该神经元的纯音频谱范围。这一结果表明，听觉皮层中的神经元在比纯音反应所显示的范围宽得多的频谱范围内进行整合。在这里，我们使用正弦调幅纯音刺激，通过电生理学方法确定了正常条件下以及微离子电泳应用GABAA受体拮抗剂荷包牡丹碱影响下，麻醉的蒙古沙鼠听觉皮层神经元频谱整合能力的高频边界。我们的结果表明，一些听觉皮层神经元在沙鼠的整个可听频谱范围内进行整合。因此，用纯音刺激确定的听觉皮层神经元的经典兴奋性频率感受野，无法对其频谱整合特性提供令人满意的描述。
