The synaptic representation of sound source location in auditory cortex.
The synaptic representation of sound source location in auditory cortex.
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DOI：
10.1523/jneurosci.2061-09.2009
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发表时间：
2009-11-11
期刊：
影响因子：
--
通讯作者：
Margrie TW
中科院分区：
文献类型：
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作者：
Chadderton P;Agapiou JP;McAlpine D;Margrie TW
听觉系统的一个关键功能是提供有关声源位置的可靠信息。在这里，我们描述了声音的位置是如何代表的突触输入到达锥体细胞内听觉皮层结合自由场声刺激在额叶方位平面与体内全细胞记录。我们发现，阈下活动是全景的，EPSP可以从所有细胞的所有位置被诱发。无论诱发最大EPSP的声音位置如何，我们观察到EPSP斜率沿对侧同侧平面沿着减慢，这反映在EPSP峰值时间的时间序列中。同侧听音诱发的EPSP峰值时间早于同侧听音，因此产生的动作电位放电时间短于同侧听音。因此，虽然尖峰电位概率反映了引起最大EPSP的空间区域，但在整个人群中，突触输入沿水平轴沿着强制执行尖峰电位延迟和精度的梯度。因此，在听觉皮层内，无论首选位置如何，突触整合的时间窗口反映了声音声源的位置，并确保空间声学信息由锥体细胞输出的相对定时表示。
A key function of the auditory system is to provide reliable information about the location of sound sources. Here, we describe how sound location is represented by synaptic input arriving onto pyramidal cells within auditory cortex by combining free field acoustic stimulation in the frontal azimuthal plane with in vivo whole-cell recordings. We found that subthreshold activity was panoramic in that EPSPs could be evoked from all locations in all cells. Irrespective of the sound location that evoked the largest EPSP, we observed a slowing in the EPSP slope along the contra-ipsilateral plane that was reflected in a temporal sequence of peak EPSP times. Contralateral sounds evoked EPSPs with earlier peak times, and consequently generated action potential firing with shorter latencies than ipsilateral sounds. Thus, while spiking probability reflected the region of space evoking the largest EPSP, across the population, synaptic inputs enforced a gradient of spike latency and precision along the horizontal axis. Thus within auditory cortex and irrespective of preferred location, the time window of synaptic integration reflects sound sound source location and ensures that spatial acoustic information is represented by relative timings of pyramidal cell output.