Department of General Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Hoppe-Seyler-Strasse 3, 72076, Tübingen, Germany.
Brain Struct Funct. 2010 Jun;214(5-6):419-33. doi: 10.1007/s00429-010-0257-x. Epub 2010 May 29.
Skilled spoken language production requires fast and accurate coordination of up to 100 muscles. A long-standing concept--tracing ultimately back to Paul Broca--assumes posterior parts of the inferior frontal gyrus to support the orchestration of the respective movement sequences prior to innervation of the vocal tract. At variance with this tradition, the insula has more recently been declared the relevant "region for coordinating speech articulation", based upon clinico-neuroradiological correlation studies. However, these findings have been criticized on methodological grounds. A survey of the clinical literature (cerebrovascular disorders, brain tumours, stimulation mapping) yields a still inconclusive picture. By contrast, functional imaging studies report more consistently hemodynamic insular responses in association with motor aspects of spoken language. Most noteworthy, a relatively small area at the junction of insular and opercular cortex was found sensitive to the phonetic-linguistic structure of verbal utterances, a strong argument for its engagement in articulatory control processes. Nevertheless, intrasylvian hemodynamic activation does not appear restricted to articulatory processes and might also be engaged in the adjustment of the autonomic system to ventilatory needs during speech production: Whereas the posterior insula could be involved in the cortical representation of respiration-related metabolic (interoceptive) states, the more rostral components, acting upon autonomic functions, might serve as a corollary pathway to "voluntary control of breathing" bound to corticospinal and -bulbar fiber tracts. For example, the insula could participate in the implementation of task-specific autonomic settings such as the maintenance of a state of relative hyperventilation during speech production.
熟练的口语产生需要快速而准确地协调多达 100 块肌肉。一个由来已久的概念——追溯到保罗·布洛卡（Paul Broca）——假设下额前回的后部区域在支配声道运动序列之前支持其协调。与这一传统观点不同，根据临床神经影像学相关性研究，脑岛最近被宣布为相关的“协调言语发音的区域”。然而，这些发现基于方法论的原因受到了批评。对临床文献（脑血管疾病、脑肿瘤、刺激映射）的调查得出的结果仍然没有定论。相比之下，功能成像研究报告了更一致的与口语运动方面相关的岛叶血流动力学反应。最值得注意的是，在脑岛和脑岛盖交界处的一个相对较小的区域对言语的语音语言结构敏感，这强烈表明它参与了发音控制过程。然而，脑岛内部的血液动力学激活似乎不仅限于发音过程，也可能参与到自主神经系统在言语产生过程中对通气需求的调整：虽然后脑岛可能参与与呼吸相关的代谢（内感受）状态的皮质代表，更靠前的部分，作用于自主功能，可能作为“呼吸的自愿控制”的相关途径，与皮质脊髓和延髓纤维束有关。例如，脑岛可能参与实施特定于任务的自主设置，例如在言语产生过程中保持相对过度通气的状态。
