Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, 60438, Frankfurt/M., Germany.
Sci Rep. 2016 Jun 30;6:29102. doi: 10.1038/srep29102.
Precise temporal coding is necessary for proper acoustic analysis. However, at cortical level, forward suppression appears to limit the ability of neurons to extract temporal information from natural sound sequences. Here we studied how temporal processing can be maintained in the bats' cortex in the presence of suppression evoked by natural echolocation streams that are relevant to the bats' behavior. We show that cortical neurons tuned to target-distance actually profit from forward suppression induced by natural echolocation sequences. These neurons can more precisely extract target distance information when they are stimulated with natural echolocation sequences than during stimulation with isolated call-echo pairs. We conclude that forward suppression does for time domain tuning what lateral inhibition does for selectivity forms such as auditory frequency tuning and visual orientation tuning. When talking about cortical processing, suppression should be seen as a mechanistic tool rather than a limiting element.
精确的时间编码对于正确的声学分析是必要的。然而,在皮质水平上,前向抑制似乎限制了神经元从自然声音序列中提取时间信息的能力。在这里,我们研究了在存在由与蝙蝠行为相关的自然回声流引起的前向抑制的情况下,蝙蝠皮质中的时间处理如何得以维持。我们表明,调谐到目标距离的皮质神经元实际上受益于自然回声序列引起的前向抑制。当用自然回声序列刺激这些神经元时,它们可以比用分离的叫声-回声对刺激时更精确地提取目标距离信息。我们的结论是,前向抑制为时间域调谐提供了类似于侧向抑制为听觉频率调谐和视觉方向调谐等选择性形式的机制工具,而不是限制因素。当谈到皮质处理时,应该将抑制视为一种机制工具,而不是限制因素。