Data from: The Yin and the Yang of Prediction: an fMRI study of semantic predictive processing

Probabilistic prediction plays a crucial role in language comprehension. When predictions are fulfilled, the resulting facilitation allows for fast, efficient processing of ambiguous, rapidly-unfolding input; when predictions are not fulfilled, the resulting error signal allows us to adapt to broader statistical changes in this input. We used functional Magnetic Resonance Imaging to examine the neuroanatomical networks engaged in semantic predictive processing and adaptation. We used a relatedness proportion semantic priming paradigm, in which we manipulated the probability of predictions while holding local semantic context constant. Under conditions of higher (versus lower) predictive validity, we replicate previous observations of reduced activity to semantically predictable words in the left anterior superior/middle temporal cortex, reflecting facilitated processing of targets that are consistent with prior semantic predictions. In addition, under conditions of higher (versus lower) predictive validity we observed significant differences in the effects of semantic relatedness within the left inferior frontal gyrus and the posterior portion of the left superior/middle temporal gyrus. We suggest that together these two regions mediated the suppression of unfulfilled semantic predictions and lexico-semantic processing of unrelated targets that were inconsistent with these predictions. Moreover, under conditions of higher (versus lower) predictive validity, a functional connectivity analysis showed that the left inferior frontal and left posterior superior/middle temporal gyrus were more tightly interconnected with one another, as well as with the left anterior cingulate cortex. The left anterior cingulate cortex was, in turn, more tightly connected to superior lateral frontal cortices and subcortical regions — a network that mediates rapid learning and adaptation and that may have played a role in switching to a more predictive mode of processing in response to the statistical structure of the wider environmental context. Together, these findings highlight close links between the networks mediating semantic prediction, executive function and learning, giving new insights into how our brains are able to flexibly adapt to our environment.

概率预测在语言理解中发挥着至关重要的作用。当预测得到验证时，由此产生的易化效应可实现对歧义性、快速涌现输入的快速高效加工；当预测未得到验证时，由此产生的误差信号则可帮助我们适应该输入中更广泛的统计规律变化。我们采用功能磁共振成像（functional Magnetic Resonance Imaging）技术，探究参与语义预测加工与适应的神经解剖网络。我们使用了关联性比例语义启动范式，在该范式中我们在保持局部语义语境恒定的前提下，对预测概率进行操控。相较于较低预测效度的条件，在较高预测效度的条件下，我们复现了此前的研究发现：左侧前颞上/中回皮层对语义可预测词汇的激活水平降低，这反映出与先前语义预测相符的目标词得到了易化加工。此外，相较于较低预测效度的条件，在较高预测效度的条件下，我们观察到左侧额下回以及左侧颞上/中回后部内的语义关联性效应存在显著差异。我们认为，这两个区域共同介导了对未验证语义预测的抑制，以及对与这些预测不符的无关目标词的词汇语义加工。进一步而言，相较于较低预测效度的条件，在较高预测效度的条件下，功能连接分析显示，左侧额下回与左侧后颞上/中回之间的功能连接更为紧密，二者同时也与左侧前扣带回皮层（anterior cingulate cortex）的连接更为紧密。而左侧前扣带回皮层又与背外侧额叶皮层及皮层下区域连接更为紧密——这一网络介导快速学习与适应，可能在响应更广泛环境背景的统计结构、切换至更具预测性的加工模式中发挥了作用。综上，这些研究结果凸显了介导语义预测、执行功能与学习的网络之间的紧密关联，为我们的大脑如何能够灵活适应周遭环境提供了新的见解。