Everts Regula, Lidzba Karen, Wilke Marko, Kiefer Claus, Mordasini Michela, Schroth Gerhard, Perrig Walter, Steinlin Maja
Paediatric Neurology, Inselspital Children's University Hospital, University Bern, Bern, Switzerland.
Hum Brain Mapp. 2009 Feb;30(2):473-83. doi: 10.1002/hbm.20523.
Cognitive functions in the child's brain develop in the context of complex adaptive processes, determined by genetic and environmental factors. Little is known about the cerebral representation of cognitive functions during development. In particular, knowledge about the development of right hemispheric (RH) functions is scarce. Considering the dynamics of brain development, localization and lateralization of cognitive functions must be expected to change with age. Twenty healthy subjects (8.6-20.5 years) were examined with fMRI and neuropsychological tests. All participants completed two fMRI tasks known to activate left hemispheric (LH) regions (language tasks) and two tasks known to involve predominantly RH areas (visual search tasks). A laterality index (LI) was computed to determine the asymmetry of activation. Group analysis revealed unilateral activation of the LH language circuitry during language tasks while visual search tasks induced a more widespread RH activation pattern in frontal, superior temporal, and occipital areas. Laterality of language increased between the ages of 8-20 in frontal (r = 0.392, P = 0.049) and temporal (r = 0.387, P = 0.051) areas. The asymmetry of visual search functions increased in frontal (r = -0.525, P = 0.009) and parietal (r = -0.439, P = 0.027) regions. A positive correlation was found between Verbal-IQ and the LI during a language task (r = 0.585, P = 0.028), while visuospatial skills correlated with LIs of visual search (r = -0.621, P = 0.018). To summarize, cognitive development is accompanied by changes in the functional representation of neuronal circuitries, with a strengthening of lateralization not only for LH but also for RH functions. Our data show that age and performance, independently, account for the increases of laterality with age.
儿童大脑中的认知功能是在由遗传和环境因素决定的复杂适应性过程中发展的。关于认知功能在发育过程中的大脑表征知之甚少。特别是，关于右半球（RH）功能发展的知识稀缺。考虑到大脑发育的动态性，认知功能的定位和侧化预计会随着年龄而变化。对20名健康受试者（8.6 - 20.5岁）进行了功能磁共振成像（fMRI）和神经心理学测试。所有参与者完成了两项已知会激活左半球（LH）区域的fMRI任务（语言任务）以及两项已知主要涉及RH区域的任务（视觉搜索任务）。计算了一个偏侧指数（LI）来确定激活的不对称性。组分析显示，在语言任务期间LH语言回路单侧激活，而视觉搜索任务在额叶、颞上叶和枕叶区域诱导出更广泛的RH激活模式。在额叶（r = 0.392，P = 0.049）和颞叶（r = 0.387，P = 0.051）区域，8 - 20岁之间语言的偏侧性增加。视觉搜索功能的不对称性在额叶（r = -0.525，P = 0.009）和顶叶（r = -0.439，P = 0.027）区域增加。在语言任务期间，言语智商（Verbal - IQ）与LI之间发现正相关（r = 0.585，P = 0.028），而视觉空间技能与视觉搜索的LI相关（r = -0.621，P = 0.018）。总之，认知发展伴随着神经回路功能表征的变化，不仅LH功能的侧化增强，RH功能的侧化也增强。我们的数据表明，年龄和表现独立地解释了随着年龄增长偏侧性的增加。
