Payne Heather, Gutierrez-Sigut Eva, Subik Joanna, Woll Bencie, MacSweeney Mairéad
Deafness, Cognition & Language Research Centre, University College London, 49 Gordon Square, London WC1H 0PD, United Kingdom; Institute of Cognitive Neuroscience, University College London, 17 Queen Square, London WC1N 3AR, United Kingdom.
Deafness, Cognition & Language Research Centre, University College London, 49 Gordon Square, London WC1H 0PD, United Kingdom.
Neuropsychologia. 2015 Jun;72:59-69. doi: 10.1016/j.neuropsychologia.2015.04.019. Epub 2015 Apr 20.
Studies to date that have used fTCD to examine language lateralisation have predominantly used word or sentence generation tasks. Here we sought to further assess the sensitivity of fTCD to language lateralisation by using a metalinguistic task which does not involve novel speech generation: rhyme judgement in response to written words. Line array judgement was included as a non-linguistic visuospatial task to examine the relative strength of left and right hemisphere lateralisation within the same individuals when output requirements of the tasks are matched. These externally paced tasks allowed us to manipulate the number of stimuli presented to participants and thus assess the influence of pace on the strength of lateralisation. In Experiment 1, 28 right-handed adults participated in rhyme and line array judgement tasks and showed reliable left and right lateralisation at the group level for each task, respectively. In Experiment 2 we increased the pace of the tasks, presenting more stimuli per trial. We measured laterality indices (LIs) from 18 participants who performed both linguistic and non-linguistic judgement tasks during the original 'slow' presentation rate (5 judgements per trial) and a fast presentation rate (10 judgements per trial). The increase in pace led to increased strength of lateralisation in both the rhyme and line conditions. Our results demonstrate for the first time that fTCD is sensitive to the left lateralised processes involved in metalinguistic judgements. Our data also suggest that changes in the strength of language lateralisation, as measured by fTCD, are not driven by articulatory demands alone. The current results suggest that at least one aspect of task difficulty, the pace of stimulus presentation, influences the strength of lateralisation during both linguistic and non-linguistic tasks.
迄今为止，使用经颅多普勒超声（fTCD）来研究语言功能偏侧化的研究主要采用单词或句子生成任务。在此，我们试图通过使用一种不涉及新语音生成的元语言任务（即对书面单词做出押韵判断）来进一步评估fTCD对语言功能偏侧化的敏感性。纳入行阵列判断作为非语言视觉空间任务，以在任务输出要求相匹配时，检查同一受试者左右半球偏侧化的相对强度。这些外部设定节奏的任务使我们能够操纵呈现给参与者的刺激数量，从而评估节奏对偏侧化强度的影响。在实验1中，28名右利手成年人参与了押韵和行阵列判断任务，并且在组水平上分别显示出每个任务可靠的左右偏侧化。在实验2中，我们加快了任务节奏，每次试验呈现更多刺激。我们测量了18名参与者的偏侧化指数（LIs），这些参与者在原始“慢速”呈现率（每次试验5次判断）和快速呈现率（每次试验10次判断）下都执行了语言和非语言判断任务。节奏的加快导致押韵和行阵列条件下偏侧化强度均增加。我们的结果首次证明，fTCD对元语言判断中涉及的左侧化过程敏感。我们的数据还表明，由fTCD测量的语言功能偏侧化强度的变化并非仅由发音需求驱动。当前结果表明，任务难度的至少一个方面，即刺激呈现的节奏，在语言和非语言任务中都会影响偏侧化强度。
