Induced Alpha-band Oscillations Reflect Ratio-dependent Number Discrimination in the Infant Brain
Induced Alpha-band Oscillations Reflect Ratio-dependent Number Discrimination in the Infant Brain
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DOI：
10.1162/jocn.2008.21162
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发表时间：
2009-12-01
影响因子：
3.2
通讯作者：
Brannon, Elizabeth M.
中科院分区：
文献类型：
--
作者：
Libertus, Melissa E.;Pruitt, Laura B.;Brannon, Elizabeth M.
行为研究表明，婴儿能够辨别环境中物体或事件的数量，同时也表明，婴儿时期的数字辨别可能与比例有关。然而，由于婴儿行为研究中使用的依赖测量的局限性，比率依赖的证据不足以证明比率依赖，从而无法在成人和非人类动物中遵守韦伯定律。我们在两个实验中解决了这个问题，这两个实验向7个月大的婴儿展示了熟悉的和新的数字，同时记录了他们大脑活动的脑电测量。这些数据提供了一致的证据，表明7个月大的婴儿的大脑发现了数字的新颖性。阿尔法带和西塔带的振荡在新奇和熟悉的数值上都有所不同。最重要的是，中线和右侧头皮后部的阿尔法频段的光谱能量受熟悉的数字和新的数字之间的比率调节。我们的发现提供了神经证据，表明婴儿期的数字辨别是比率依赖的，并遵循韦伯定律，从而表明这些认知过程在发展过程中是连续的。结果也与额叶和顶叶皮质的网络支持在人类生命的第一年依赖比率的数字辨别的想法一致，这与成人和年龄较大的儿童的神经成像研究报告的一致。
Behavioral studies show that infants are capable of discriminating the number of objects or events in their environment, while also suggesting that number discrimination in infancy may be ratio-dependent. However, due to limitations of the dependent measures used with infant behavioral studies, the evidence for ratio dependence falls short of the vast psychophysical datasets that have established ratio dependence, and thus, adherence to Weber's Law in adults and non-human animals. We addressed this issue in two experiments that presented 7-month-old infants with familiar and novel numerosities while electroencephalogram measures of their brain activity were recorded. These data provide convergent evidence that the brains of 7-month-old infants detected numerical novelty. Alpha-band and theta-band oscillations both differed for novel and familiar numerical values. Most importantly, spectral power in the alpha band over midline and right posterior scalp sites was modulated by the ratio between the familiar and novel numerosities. Our findings provide neural evidence that numerical discrimination in infancy is ratio dependent and follows Weber's Law, thus indicating continuity of these cognitive processes over development. Results are also consistent with the idea that networks in the frontal and parietal cortices support ratio-dependent number discrimination in the first year of human life, consistent with what has been reported in neuroimaging studies in adults and older children.