Exploiting development to evaluate auditory encoding of amplitude modulation.
Exploiting development to evaluate auditory encoding of amplitude modulation.
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利用开发来评估振幅调制的听觉编码。
DOI：
10.1523/jneurosci.3340-10.2010
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发表时间：
2010-11-17
期刊：
影响因子：
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通讯作者：
Sanes DH
中科院分区：
文献类型：
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作者：
Rosen MJ;Semple MN;Sanes DH
在发展过程中，对多种感知的检测逐渐成熟。这为研究表现差异背后的神经机制提供了一个自然的系统：神经活动的那些方面与行为表现一起成熟，更有可能有助于检测。原则上，对表现的限制可能是由于不成熟的感觉编码机制或对已经成熟的感觉表征的不成熟的解码。为了在清醒沙土鼠的听觉皮质中评估这些替代方案，我们测量了对正弦调幅(SAM)刺激的神经检测，其行为检测阈值显示出更长的成熟期。对青少年和成人的单一单位反应的比较表明，青少年对静态音调的编码类似于成人，但对SAM深度的反应是不成熟的。由于知觉表现可以反映动物最敏感神经元的活动，我们分析了单个神经元的d素数曲线，并在幼年和成年动物中找到了具有高度敏感阈值的等量百分比。相比之下，知觉表现可能反映了具有一系列敏感度的神经元信息的汇集。我们评估了一个假设输入群体在下游目标神经元处收敛的汇集模型，发现青少年的SAM检测阈值较差。因此，如果Sam检测是基于最敏感的神经元，那么不成熟的行为表现最好地解释为不成熟的解码机制。然而，如果SAM检测是基于群体反应，那么不成熟的检测阈值更有可能是由于感觉表征的不足。
During development, detection for many percepts matures gradually. This provides a natural system in which to investigate the neural mechanisms underlying performance differences: those aspects of neural activity that mature in conjunction with behavioral performance are more likely to subserve detection. In principle, the limitations on performance could be due to either immature sensory encoding mechanisms or an immature decoding of an already-mature sensory representation. To evaluate these alternatives in awake gerbil auditory cortex, we measured neural detection of sinusoidally amplitude modulated (sAM) stimuli, for which behavioral detection thresholds display a prolonged maturation. A comparison of single unit responses in juveniles and adults revealed that encoding of static tones was adult-like in juveniles, but responses to sAM depth were immature. Since perceptual performance may reflect the activity of an animal’s most sensitive neurons, we analyzed the d prime curves of single neurons, and found an equivalent percentage with highly sensitive thresholds in juvenile and adult animals. In contrast, perceptual performance may reflect the pooling of information from neurons with a range of sensitivities. We evaluated a pooling model that assumes convergence of a population of inputs at a downstream target neuron, and found poorer sAM detection thresholds for juveniles. Thus, if sAM detection is based on the most sensitive neurons, then immature behavioral performance is best explained by an immature decoding mechanism. However, if sAM detection is based on a population response, then immature detection thresholds are more likely due to an inadequate sensory representation.