Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
Cereb Cortex. 2011 Jan;21(1):166-77. doi: 10.1093/cercor/bhq073. Epub 2010 May 5.
Central processing of acoustic signals is assumed to take place in a stereotypical spatial and temporal pattern involving different fields of auditory cortex. So far, cortical propagating waves representing such patterns have mainly been demonstrated by optical imaging, repeatedly in the visual and somatosensory cortex. In this study, the surface of rat auditory cortex was mapped by recording local field potentials (LFPs) in response to a broadband acoustic stimulus. From the peak amplitudes of LFPs, cortical activation maps were constructed over 4 cortical auditory fields. Whereas response onset had same latencies across primary auditory field (A1), anterior auditory field (AAF), and ventral auditory field and longer latencies in posterior auditory field, activation maps revealed a reproducible wavelike pattern of activity propagating for ∼45 ms poststimulus through all cortical fields. The movement observed started with 2 waves within the primary auditory fields A1 and AAF moving from ventral to dorsal followed by a motion from rostral to caudal, passing continuously through higher-order fields. The pattern of propagating waves was well reproducible and showed only minor changes if different anesthetics were used. The results question the classical "hierarchical" model of cortical areas and demonstrate that the different fields process incoming information as a functional unit.
人们认为，声学信号的中央处理是按照涉及不同听觉皮层区域的典型的时空模式进行的。到目前为止，通过光学成像技术已经在视觉和躯体感觉皮层中反复证明了代表这种模式的皮质传播波。在这项研究中，通过记录宽带声刺激反应中的局部场电位（LFPs），对大鼠听觉皮层的表面进行了映射。根据 LFPs 的峰值幅度，在 4 个听觉皮层区域上构建了皮层激活图。虽然初级听觉域（A1）、前听觉域（AAF）和腹侧听觉域的反应起始具有相同的潜伏期，而后听觉域的潜伏期较长，但激活图显示出一种可重复的、类似于波的活动模式，在刺激后约 45 毫秒内通过所有皮层区域传播。观察到的运动始于初级听觉域 A1 和 AAF 内的 2 个波，从腹侧向背侧移动，然后从额侧向尾侧移动，连续穿过高级域。传播波的模式具有很好的可重复性，如果使用不同的麻醉剂，只会有微小的变化。这些结果对经典的皮层区域“层次”模型提出了质疑，并证明不同的区域将传入的信息作为一个功能单元进行处理。
