Neural Correlates of Semantic Prediction and Resolution in Sentence Processing.
Neural Correlates of Semantic Prediction and Resolution in Sentence Processing.
复制标题
DOI：
10.1523/jneurosci.2800-16.2017
复制
发表时间：
2017-05-03
期刊：
影响因子：
--
通讯作者：
Pulvermüller F
中科院分区：
文献类型：
--
作者：
Grisoni L;Miller TM;Pulvermüller F
大多数关于语言理解的脑成像研究都集中在有意义的刺激之后的活动上。我们用高密度EEG测试成年人类参与者，结果表明，在呈现关键词之前，上下文诱导的语义预测就已经通过神经生理指标反映出来，因此我们称之为语义准备潜力（SRP）。如果先前的句子上下文约束即将到来的语义内容（高约束上下文），但不是在不可预测的（低约束）上下文中，SRP先于关键词。具体的语义预测由运动系统内的SRP源索引-在背外侧手部运动区域中用于预期的手部相关词（例如，“写”），但在腹侧运动皮层的脸相关的话（“谈”）。与肯定句相比，否定句导致内侧前额叶和更广泛的运动源激活，后者与否定预期概念的替代品的预测语义计算一致。否定句中语义替代的预测加工进一步得到了~ 400 ms（N400）的负向事件相关电位的支持，该电位仅在高约束肯定语境中对语义不一致的句尾有典型的增强作用，而对高约束否定语境中的语义不一致的句尾没有增强作用。这些大脑动力学揭示了句子理解中语义预测和解决（匹配与错误）处理之间的相互作用。大多数神经科学家都认为，预测机制对于理解大脑的基本功能和高级功能都非常重要。这与直接反映预测特定方面的大脑测量的稀疏形成对比，因为它们与语言和思维的处理有关。在这里，我们表明，当关键词强烈预期在他们的句子背景下，预测性的大脑反应反映了这些预期的符号的意义特征已经出现之前。语义预测的粒度是如此精细，以至于感觉运动和内侧前额叶皮层中的皮层源甚至可以区分预测的面部或手部相关动作词（例如，单词“舔”或“挑”）以及肯定句和否定句之间的含义。
Most brain-imaging studies of language comprehension focus on activity following meaningful stimuli. Testing adult human participants with high-density EEG, we show that, already before the presentation of a critical word, context-induced semantic predictions are reflected by a neurophysiological index, which we therefore call the semantic readiness potential (SRP). The SRP precedes critical words if a previous sentence context constrains the upcoming semantic content (high-constraint contexts), but not in unpredictable (low-constraint) contexts. Specific semantic predictions were indexed by SRP sources within the motor system—in dorsolateral hand motor areas for expected hand-related words (e.g., “write”), but in ventral motor cortex for face-related words (“talk”). Compared with affirmative sentences, negated ones led to medial prefrontal and more widespread motor source activation, the latter being consistent with predictive semantic computation of alternatives to the negated expected concept. Predictive processing of semantic alternatives in negated sentences is further supported by a negative-going event-related potential at ∼400 ms (N400), which showed the typical enhancement to semantically incongruent sentence endings only in high-constraint affirmative contexts, but not to high-constraint negated ones. These brain dynamics reveal the interplay between semantic prediction and resolution (match vs error) processing in sentence understanding. SIGNIFICANCE STATEMENT Most neuroscientists agree on the eminent importance of predictive mechanisms for understanding basic as well as higher brain functions. This contrasts with a sparseness of brain measures that directly reflects specific aspects of prediction, as they are relevant in the processing of language and thought. Here we show that when critical words are strongly expected in their sentence context, a predictive brain response reflects meaning features of these anticipated symbols already before they appear. The granularity of the semantic predictions was so fine grained that the cortical sources in sensorimotor and medial prefrontal cortex even distinguished between predicted face- or hand-related action words (e.g., the words “lick” or “pick”) and between affirmative and negated sentence meanings.