Upadhyay Jaymin, Silver Andrew, Knaus Tracey A, Lindgren Kristen A, Ducros Mathieu, Kim Dae-Shik, Tager-Flusberg Helen
Center for Biomedical Imaging, Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts 02118, USA.
J Neurosci. 2008 Mar 26;28(13):3341-9. doi: 10.1523/JNEUROSCI.4434-07.2008.
Language processing involves multiple neuronal structures in the human auditory cortex. Although a variety of neuroimaging and mapping techniques have been implemented to better understand language processing at the level of the auditory cortex, much is unknown regarding how and by what pathways these structures interact during essential tasks such as sentence comprehension. In this study, the effective and structural connectivity at the level of the auditory cortex were investigated. First, blood oxygenation level-dependent (BOLD) responses were measured with time-resolved functional magnetic resonance imaging (fMRI) during audition of short sentences. Once BOLD activation maps were obtained, the effective connectivity between primary auditory cortex and the surrounding auditory regions on the supratemporal plane and superior temporal gyrus (STG) were investigated using Granger causality mapping (GCM). Effective connectivity was observed between the primary auditory cortex and (1) the lateral planum polare and anterior STG, and (2) the lateral planum temporale and posterior STG. By using diffusion tensor probabilistic mapping (DTPM), rostral and caudal fiber pathways were detected between regions depicting effective connectivity. The effective and structural connectivity results of the present study provide further insight as to how auditory stimuli (i.e., human language) is processed at the level of the auditory cortex. Furthermore, combining BOLD fMRI-based GCM and DTPM analysis could provide a novel means to study effective and structural connectivity not only in the auditory cortex, but also in other cortical regions.
语言处理涉及人类听觉皮层中的多个神经元结构。尽管已经采用了各种神经成像和映射技术来更好地理解听觉皮层水平上的语言处理，但对于这些结构在诸如句子理解等基本任务中如何相互作用以及通过何种途径相互作用，仍有许多未知之处。在本研究中，对听觉皮层水平的有效连接性和结构连接性进行了研究。首先，在听短句时，使用时间分辨功能磁共振成像（fMRI）测量血氧水平依赖（BOLD）反应。一旦获得BOLD激活图，就使用格兰杰因果关系映射（GCM）研究初级听觉皮层与颞上平面和颞上回（STG）周围听觉区域之间的有效连接性。在初级听觉皮层与（1）外侧极平面和前STG，以及（2）外侧颞平面和后STG之间观察到了有效连接性。通过使用扩散张量概率映射（DTPM），在描绘有效连接性的区域之间检测到了前后纤维束。本研究的有效连接性和结构连接性结果为听觉皮层水平上如何处理听觉刺激（即人类语言）提供了进一步的见解。此外，将基于BOLD fMRI的GCM和DTPM分析相结合，不仅可以为研究听觉皮层，还可以为研究其他皮层区域的有效连接性和结构连接性提供一种新方法。
