2013年11月22日訊 /生物谷BIOON/--我們通過閱讀或者聽其他人說話能夠了解到各種信息，如人，物體，事件等。我們這種通過文字或語音理解內容的能力稱之為"話語理解力"。。近期發表在Brain雜誌上的文章稱，科學家找到了話語理解能力的神經環路基礎。
未來研究該問題，科學家招募了145位參與越南戰爭的美國老兵，他們在戰爭中都遭受了頭部損傷。該文章的通訊作者Barbey博士稱，彈片會引起局部腦組織損傷，不像中風或其他神經疾病會引起多區域的腦損傷。該局部腦損傷有利於科學家研究話語理解能力的相關腦區。
Barbey博士稱，局部腦損傷的神經心理病人對研究腦區作用有重要意義。
科學家分析了志願者的CT掃描結果，並三維重建了大腦皮層結果。科學家分析了語言理解能力欠缺的志願者的特定損傷的腦區，發現前額葉和頂葉環路對語言理解能力有重要作用。
Barbey博士稱，相對於傳統的參與語言過程的腦區，我們的發現表明話語理解能力需要更高級的神經環路，這將有助於整合新信息與記憶的信息。
Barbey博士稱，話語理解能力是人類社會行為的標誌。通過研究該能力的神經環路機制，我們進一步的了解了認知過程的神經機制。（生物谷Bioon.com）
Damage to the anterior arcuate fasciculus predicts non-fluent speech production in aphasia
J. Fridriksson, D. Guo, P. Fillmore, A. Holland, C. Rorden.
Non-fluent aphasia implies a relatively straightforward neurological condition characterized by limited speech output. However, it is an umbrella term for different underlying impairments affecting speech production. Several studies have sought the critical lesion location that gives rise to non-fluent aphasia. The results have been mixed but typically implicate anterior cortical regions such as Broca’s area, the left anterior insula, and deep white matter regions. To provide a clearer picture of cortical damage in non-fluent aphasia, the current study examined brain damage that negatively influences speech fluency in patients with aphasia. It controlled for some basic speech and language comprehension factors in order to better isolate the contribution of different mechanisms to fluency, or its lack. Cortical damage was related to overall speech fluency, as estimated by clinical judgements using the Western Aphasia Battery speech fluency scale, diadochokinetic rate, rudimentary auditory language comprehension, and executive functioning (scores on a matrix reasoning test) in 64 patients with chronic left hemisphere stroke. A region of interest analysis that included brain regions typically implicated in speech and language processing revealed that non-fluency in aphasia is primarily predicted by damage to the anterior segment of the left arcuate fasciculus. An improved prediction model also included the left uncinate fasciculus, a white matter tract connecting the middle and anterior temporal lobe with frontal lobe regions, including the pars triangularis. Models that controlled for diadochokinetic rate, picture-word recognition, or executive functioning also revealed a strong relationship between anterior segment involvement and speech fluency. Whole brain analyses corroborated the findings from the region of interest analyses. An additional exploratory analysis revealed that involvement of the uncinate fasciculus adjudicated between Broca’s and global aphasia, the two most common kinds of non-fluent aphasia. In summary, the current results suggest that the anterior segment of the left arcuate fasciculus, a white matter tract that lies deep to posterior portions of Broca’s area and the sensory-motor cortex, is a robust predictor of impaired speech fluency in aphasic patients, even when motor speech, lexical processing, and executive functioning are included as co-factors. Simply put, damage to those regions results in non-fluent aphasic speech; when they are undamaged, fluent aphasias result.