Institute of Biology II, RWTH Aachen University, Worringerweg 3, 52074, Aachen, Germany.
Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY, 10461, USA.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2020 Jul;206(4):477-498. doi: 10.1007/s00359-020-01410-0. Epub 2020 Mar 5.
Interaural time and level differences are important cues for sound localization. We wondered whether the broadband information contained in these two cues could fully explain the behavior of barn owls and responses of midbrain neurons in these birds. To tackle this problem, we developed a novel approach based on head-related transfer functions. These filters contain the complete information present at the eardrum. We selected positions in space characterized by equal broadband interaural time and level differences. Stimulation from such positions provides reduced information to the owl. We show that barn owls are able to discriminate between such positions. In many cases, but not all, the owls may have used spectral components of interaural level differences that exceeded the known behavioral resolution and variability for discrimination. Alternatively, the birds may have used template matching. Likewise, neurons in the optic tectum of the barn owl, a nucleus involved in sensorimotor integration, contained more information than is available in the broadband interaural time and level differences. Thus, these data show that more information is available and used by barn owls for sound localization than carried by broadband interaural time and level differences.
耳间时间和强度差是声音定位的重要线索。我们想知道这些线索中包含的宽带信息是否可以完全解释欧椋鸟的行为和这些鸟类中中脑神经元的反应。为了解决这个问题，我们基于头相关传递函数开发了一种新方法。这些滤波器包含了鼓膜处存在的所有完整信息。我们选择了具有相等宽带耳间时间和强度差的空间位置。来自这些位置的刺激会向鸟类提供较少的信息。我们表明，欧椋鸟能够区分这些位置。在许多情况下，但不是所有情况下，鸟类可能使用了超过已知行为分辨率和可辨别的耳间强度差的光谱成分。或者，鸟类可能使用了模板匹配。同样，参与感觉运动整合的欧椋鸟视顶盖中的神经元包含的信息多于宽带耳间时间和强度差中提供的信息。因此，这些数据表明，欧椋鸟用于声音定位的信息比宽带耳间时间和强度差中提供的信息更多。
