A Role for Auditory Corticothalamic Feedback in the Perception of Complex Sounds.
A Role for Auditory Corticothalamic Feedback in the Perception of Complex Sounds.
复制标题
DOI：
10.1523/jneurosci.0397-17.2017
复制
发表时间：
2017-06-21
期刊：
影响因子：
--
通讯作者：
Bajo VM
中科院分区：
文献类型：
--
作者：
Homma NY;Happel MFK;Nodal FR;Ohl FW;King AJ;Bajo VM
来自初级听觉皮层（A1）的反馈信号可以塑造内侧膝状体（MGBv）腹侧部神经元的感受野特性。然而，皮质丘脑调制的行为意义是未知的。本研究的目的是阐明这一下行通路在复杂声音感知中的作用。我们测试了成年雌性雪貂的能力，以检测到一个失谐的谐波在一个复杂的音调使用积极的条件去/不去的行为范例之前和之后的输入从第六层在A1到MGBV是双边和选择性地消除使用发色团为目标的激光光解。MGBv神经元通过其短的潜伏期和尖锐的调谐曲线来鉴定。它们对谐波复音反应强烈，当复音中的一个频率分量失调时，放电率和时间模式变化会增加。在MGBV中注射与光敏发色团缀合的荧光微珠，并且在逆行运输到皮质细胞体之后，通过A1的红外激光照射诱导细胞凋亡。这导致了约60%的VIA 1-MGBV层神经元的选择性损失。损伤后，失调检测受损，表现为d′值降低，心理测量曲线向更高失调值移动，阈值增加，而当水平线索也可用时，辨别性能不受影响。我们的研究结果表明，A1-MGBv皮质丘脑反馈有助于检测谐波，其中一个最重要的分组线索的感知复杂的声音。重要性陈述对复杂听觉场景的感知是基于大脑将属于同一来源的声音成分分组并将它们与属于不同来源的声音成分分离的能力。由于两个人同时说话可能会在他们的音高不同，感知声音的谐波结构是非常重要的听觉场景分析。在这里，我们展示了丘脑的失调敏感性，以及雪貂在复杂声音中检测失调谐波的正常能力所需的初级听觉皮层的反馈。这些结果为大脑中下行感觉通路的功能提供了新的见解，并表明这种皮质丘脑回路在场景分析中发挥着重要作用。
Feedback signals from the primary auditory cortex (A1) can shape the receptive field properties of neurons in the ventral division of the medial geniculate body (MGBv). However, the behavioral significance of corticothalamic modulation is unknown. The aim of this study was to elucidate the role of this descending pathway in the perception of complex sounds. We tested the ability of adult female ferrets to detect the presence of a mistuned harmonic in a complex tone using a positive conditioned go/no-go behavioral paradigm before and after the input from layer VI in A1 to MGBv was bilaterally and selectively eliminated using chromophore-targeted laser photolysis. MGBv neurons were identified by their short latencies and sharp tuning curves. They responded robustly to harmonic complex tones and exhibited an increase in firing rate and temporal pattern changes when one frequency component in the complex tone was mistuned. Injections of fluorescent microbeads conjugated with a light-sensitive chromophore were made in MGBv, and, following retrograde transport to the cortical cell bodies, apoptosis was induced by infrared laser illumination of A1. This resulted in a selective loss of ∼60% of layer VI A1-MGBv neurons. After the lesion, mistuning detection was impaired, as indicated by decreased d′ values, a shift of the psychometric curves toward higher mistuning values, and increased thresholds, whereas discrimination performance was unaffected when level cues were also available. Our results suggest that A1-MGBv corticothalamic feedback contributes to the detection of harmonicity, one of the most important grouping cues in the perception of complex sounds. SIGNIFICANCE STATEMENT Perception of a complex auditory scene is based on the ability of the brain to group those sound components that belong to the same source and to segregate them from those belonging to different sources. Because two people talking simultaneously may differ in their voice pitch, perceiving the harmonic structure of sounds is very important for auditory scene analysis. Here we demonstrate mistuning sensitivity in the thalamus and that feedback from the primary auditory cortex is required for the normal ability of ferrets to detect a mistuned harmonic within a complex sound. These results provide novel insight into the function of descending sensory pathways in the brain and suggest that this corticothalamic circuit plays an important role in scene analysis.