Rossell S L, Bullmore E T, Williams S C, David A S
Macquarie Centre for Cognitive Science (MACCS), Macquarie University, NSW 2109, Sydney, Australia.
Neuropsychologia. 2001;39(11):1167-76. doi: 10.1016/s0028-3932(01)00049-5.
Semantic relations may be studied using the experimental technique known as semantic priming, in which a word 'primes' the processing of a related target (e.g. lion-tiger), following a short delay. Priming may be automatic or, with longer delays, under more controlled processing. This study used functional magnetic resonance imaging (fMRI) to examine the cerebral activation during two lexical-decision semantic priming experiments, with a short and long delay, representing automatic and controlled processing, respectively. A further two un-primed lexical-decision tasks were performed to distinguish cerebral activation specific to semantic priming itself from those utilised during lexical-decision processes. Distinct regions of anterior cingulate cortex (ACC) were critical to automatic and controlled semantic priming, whilst the putamen and hippocampal complex responded differently to unrelated and semantically related prime-target pairs. Lexical-decision alone revealed activation in posterior temporal cortex especially on the left, in agreement with previous neuroimaging studies. The results provide a plausible neural substrate for common semantic relations independent of task demands and further emphasise the regional functional specialisation of the ACC.
语义关系可以通过一种称为语义启动的实验技术来研究，在这种技术中，一个单词会在短暂延迟后“启动”对相关目标词的加工（例如，狮子-老虎）。启动可以是自动的，或者在延迟较长时，处于更受控制的加工过程中。本研究使用功能磁共振成像（fMRI）来检查在两个词汇判断语义启动实验过程中的大脑激活情况，分别有短延迟和长延迟，分别代表自动加工和受控制加工。还进行了另外两个无启动的词汇判断任务，以区分语义启动本身特有的大脑激活与词汇判断过程中所利用的激活。前扣带回皮质（ACC）的不同区域对自动和受控制的语义启动至关重要，而壳核和海马复合体对不相关和语义相关的启动-目标词对的反应不同。仅词汇判断就显示颞叶后部皮质尤其是左侧有激活，这与先前的神经影像学研究一致。这些结果为独立于任务需求的常见语义关系提供了一个合理的神经基础，并进一步强调了ACC的区域功能特化。
