Abstract

Catecholamine (CA) function has been widely implicated in cognitive functions that are tied to the prefrontal cortex and striatal areas. The present study investigated the effects of methylphenidate, which is a CA agonist, on the electroencephalogram (EEG) response related to semantic processing using a double-blind, placebo-controlled, randomized, crossover, within-subject design. Forty-eight healthy participants read semantically congruent or incongruent sentences after receiving 20-mg methylphenidate or a placebo while their brain activity was monitored with EEG. To probe whether the catecholaminergic modulation is task-dependent, in one condition participants had to focus on comprehending the sentences, while in the other condition, they only had to attend to the font size of the sentence. The results demonstrate that methylphenidate has a task-dependent effect on semantic processing. Compared to placebo, when semantic processing was task-irrelevant, methylphenidate enhanced the detection of semantic incongruence as indexed by a larger N400 amplitude in the incongruent sentences; when semantic processing was task-relevant, methylphenidate induced a larger N400 amplitude in the semantically congruent condition, which was followed by a larger late positive complex effect. These results suggest that CA-related neurotransmitters influence language processing, possibly through the projections between the prefrontal cortex and the striatum, which contain many CA receptors.

中文翻译：

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句子理解中语义加工的儿茶酚胺能调节。

摘要

儿茶酚胺 (CA) 功能广泛涉及与前额叶皮层和纹状体区域相关的认知功能。本研究使用双盲、安慰剂对照、随机、交叉、受试者内设计，研究了哌甲酯（一种 CA 激动剂）对与语义处理相关的脑电图 (EEG) 反应的影响。48 名健康参与者在接受 20 毫克哌甲酯或安慰剂后阅读语义一致或不一致的句子，同时用 EEG 监测他们的大脑活动。为了探究儿茶酚胺能调制是否依赖于任务，在一种情况下，参与者必须专注于理解句子，而在另一种情况下，他们只需要注意句子的字体大小。结果表明哌甲酯对语义处理具有任务依赖效应。与安慰剂相比，当语义处理与任务无关时，哌醋甲酯增强了对语义不一致的检测，这由不一致句子中较大的 N400 幅度表示；当语义处理与任务相关时，哌醋甲酯在语义一致的条件下诱导了更大的 N400 振幅，随后是更大的晚期正复合效应。这些结果表明 CA 相关的神经递质影响语言处理，可能是通过前额叶皮层和纹状体之间的投射，其中包含许多 CA 受体。哌醋甲酯增强了语义不一致的检测，因为不一致句子中较大的 N400 幅度表明；当语义处理与任务相关时，哌醋甲酯在语义一致的条件下诱导了更大的 N400 振幅，随后是更大的晚期正复合效应。这些结果表明 CA 相关的神经递质影响语言处理，可能是通过前额叶皮层和纹状体之间的投射，其中包含许多 CA 受体。哌醋甲酯增强了语义不一致的检测，因为不一致句子中较大的 N400 幅度表明；当语义处理与任务相关时，哌醋甲酯在语义一致的条件下诱导了更大的 N400 振幅，随后是更大的晚期正复合效应。这些结果表明 CA 相关的神经递质影响语言处理，可能是通过前额叶皮层和纹状体之间的投射，其中包含许多 CA 受体。