Schizophrenia as failure of left hemispheric dominance for the phonological component of language.
Schizophrenia as failure of left hemispheric dominance for the phonological component of language.
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DOI：
10.1371/journal.pone.0004507
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发表时间：
2009
期刊：
影响因子：
3.7
通讯作者：
Stegagno L
中科院分区：
文献类型：
--
作者：
Angrilli A;Spironelli C;Elbert T;Crow TJ;Marano G;Stegagno L
T. J. Crow 认为，与智人语言半球优势进化相关的遗传变异会带来精神分裂症症状的危险。缺乏语言（尤其是语音成分）的典型左半球优势的个体，出现幻听和妄想等典型症状的风险会增加。十二名接受低水平抗精神病药物治疗的精神分裂症患者和十二名匹配的健康对照者参加了一项与事件相关的电位实验。受试者在三个任务中匹配单词对：押韵/语音、语义判断和单词识别。从 26 个头皮电极记录慢诱发电位，并计算刺激间隔期间前部和后部区域的偏侧性指数。在语音处理过程中，精神分裂症患者未能实现健康对照者一贯观察到的左半球优势。该效应涉及前部（额颞）大脑区域，并且针对语音任务是特定的；当受试者在语义任务或单词识别期间（即通常激活两个半球更广泛区域的任务期间）处理相同的刺激材料时，组间差异很小或不存在。我们首次展示了精神分裂症患者大脑的偏侧化缺陷如何特定于语言的语音成分。这种半球优势的丧失可以解释典型的症状，例如当一个人自己的想法被视为外部入侵的声音时。这一变化可以解释为“半球犹豫不决”的结果，即未能在一个半球分离语音印迹。
T. J. Crow suggested that the genetic variance associated with the evolution in Homo sapiens of hemispheric dominance for language carries with it the hazard of the symptoms of schizophrenia. Individuals lacking the typical left hemisphere advantage for language, in particular for phonological components, would be at increased risk of the typical symptoms such as auditory hallucinations and delusions. Twelve schizophrenic patients treated with low levels of neuroleptics and twelve matched healthy controls participated in an event-related potential experiment. Subjects matched word-pairs in three tasks: rhyming/phonological, semantic judgment and word recognition. Slow evoked potentials were recorded from 26 scalp electrodes, and a laterality index was computed for anterior and posterior regions during the inter stimulus interval. During phonological processing individuals with schizophrenia failed to achieve the left hemispheric dominance consistently observed in healthy controls. The effect involved anterior (fronto-temporal) brain regions and was specific for the Phonological task; group differences were small or absent when subjects processed the same stimulus material in a Semantic task or during Word Recognition, i.e. during tasks that typically activate more widespread areas in both hemispheres. We show for the first time how the deficit of lateralization in the schizophrenic brain is specific for the phonological component of language. This loss of hemispheric dominance would explain typical symptoms, e.g. when an individual's own thoughts are perceived as an external intruding voice. The change can be interpreted as a consequence of “hemispheric indecision”, a failure to segregate phonological engrams in one hemisphere.