Gourévitch Boris, Noreña Arnaud, Shaw Gregory, Eggermont Jos J
Department of Physiology and Biophysics, University of Calgary, Calgary, Alberta, Canada.
Cereb Cortex. 2009 Jun;19(6):1448-61. doi: 10.1093/cercor/bhn184. Epub 2008 Oct 14.
In order to investigate how the auditory scene is analyzed and perceived, auditory spectrotemporal receptive fields (STRFs) are generally used as a convenient way to describe how frequency and temporal sound information is encoded. However, using broadband sounds to estimate STRFs imperfectly reflects the way neurons process complex stimuli like conspecific vocalizations insofar as natural sounds often show limited bandwidth. Using recordings in the primary auditory cortex of anesthetized cats, we show that presentation of narrowband stimuli not including the best frequency of neurons provokes the appearance of residual peaks and increased firing rate at some specific spectral edges of stimuli compared with classical STRFs obtained from broadband stimuli. This result is the same for STRFs obtained from both spikes and local field potentials. Potential mechanisms likely involve release from inhibition. We thus emphasize some aspects of context dependency of STRFs, that is, how the balance of inhibitory and excitatory inputs is able to shape the neural response from the spectral content of stimuli.
为了研究听觉场景是如何被分析和感知的，听觉频谱时间感受野（STRF）通常被用作一种便捷的方式来描述频率和时间声音信息是如何被编码的。然而，使用宽带声音来估计STRF并不能完美地反映神经元处理诸如同种发声等复杂刺激的方式，因为自然声音的带宽往往有限。通过在麻醉猫的初级听觉皮层进行记录，我们发现，与从宽带刺激获得的经典STRF相比，呈现不包括神经元最佳频率的窄带刺激会在刺激的某些特定频谱边缘引发残余峰值的出现和 firing 率的增加。从尖峰和局部场电位获得的STRF结果都是如此。潜在机制可能涉及抑制的释放。因此，我们强调了STRF上下文依赖性的一些方面，即抑制性和兴奋性输入的平衡如何能够根据刺激的频谱内容塑造神经反应。
