Brain Research Unit, O.V. Lounasmaa Laboratory, School of Science, Aalto University, Espoo, Finland.
PLoS One. 2013 May 29;8(5):e64489. doi: 10.1371/journal.pone.0064489. Print 2013.
Earlier studies have shown considerable intersubject synchronization of brain activity when subjects watch the same movie or listen to the same story. Here we investigated the across-subjects similarity of brain responses to speech and non-speech sounds in a continuous audio drama designed for blind people. Thirteen healthy adults listened for ∼19 min to the audio drama while their brain activity was measured with 3 T functional magnetic resonance imaging (fMRI). An intersubject-correlation (ISC) map, computed across the whole experiment to assess the stimulus-driven extrinsic brain network, indicated statistically significant ISC in temporal, frontal and parietal cortices, cingulate cortex, and amygdala. Group-level independent component (IC) analysis was used to parcel out the brain signals into functionally coupled networks, and the dependence of the ICs on external stimuli was tested by comparing them with the ISC map. This procedure revealed four extrinsic ICs of which two-covering non-overlapping areas of the auditory cortex-were modulated by both speech and non-speech sounds. The two other extrinsic ICs, one left-hemisphere-lateralized and the other right-hemisphere-lateralized, were speech-related and comprised the superior and middle temporal gyri, temporal poles, and the left angular and inferior orbital gyri. In areas of low ISC four ICs that were defined intrinsic fluctuated similarly as the time-courses of either the speech-sound-related or all-sounds-related extrinsic ICs. These ICs included the superior temporal gyrus, the anterior insula, and the frontal, parietal and midline occipital cortices. Taken together, substantial intersubject synchronization of cortical activity was observed in subjects listening to an audio drama, with results suggesting that speech is processed in two separate networks, one dedicated to the processing of speech sounds and the other to both speech and non-speech sounds.
先前的研究表明，当受试者观看同一部电影或聆听同一个故事时，大脑活动存在显著的主体间同步性。在这里，我们研究了为盲人设计的连续音频剧中言语和非言语声音对大脑反应的跨主体相似性。13 名健康成年人在 3T 功能磁共振成像（fMRI）下聆听音频剧约 19 分钟，同时测量他们的大脑活动。一个跨主体相关性（ISC）图，用于评估整个实验中刺激驱动的外在大脑网络，在颞叶、额叶和顶叶皮层、扣带皮层和杏仁核中显示出统计学上显著的 ISC。组水平独立成分（IC）分析用于将大脑信号划分为功能耦合网络，并通过将它们与 ISC 图进行比较来测试 IC 对外部刺激的依赖性。该程序揭示了四个外在 IC，其中两个覆盖听觉皮层的不重叠区域——受到言语和非言语声音的调制。另外两个外在 IC，一个左半球偏向的和另一个右半球偏向的，与言语有关，包括颞上回、颞极和左角回和下眶回。在 ISC 较低的区域，四个内在 IC 定义为内在波动，与言语相关的时间过程或所有声音相关的外在 IC 相似。这些 IC 包括颞上回、前岛叶以及额、顶和中线枕叶皮质。总的来说，在聆听音频剧的受试者中观察到皮质活动的主体间同步性显著，结果表明言语在两个独立的网络中进行处理，一个专门用于处理言语声音，另一个则用于处理言语和非言语声音。
