Newborns have a functioning sense of smell at birth, which appears to be highly significant for feeding and bonding. Still, little is known about the cerebral odor processing in this age group. Studies of olfactory function relied mostly on behavioral, autonomic, and facial responses of infants. The aim of the present study was to investigate central odor processing in infants focusing on electroencephalography (EEG)-derived responses to biologically significant odors, namely a food and a non-food odor. A total of 21 term-born, healthy infants participated (11 boys and 10 girls; age range 2–9 months, mean 5.3 ± 2.2 months). Odor stimuli were presented using a computer-controlled olfactometer. Breast milk was used as food odor. Farnesol was presented as a non-food odor. In addition, odorless air was used as a control stimulus. Each stimulus was presented 30 times for 1 s with an interstimulus interval of 20 s. EEG was recorded from 9 electrodes and analyzed in the frequency domain. EEG amplitudes in the delta frequency band differed significantly after presentation of food (breast milk) odor in comparison to the control condition and the non-food odor (farnesol). These changes were observed at the frontal recording positions. The present study indicates that central odor processing differs between a food and a non-food odor in infants. Results are interpreted in terms of focused attention towards a physiologically relevant odor (breast milk), suggesting that olfactory stimuli are of specific significance in this age group.

中文翻译：

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婴儿花香和母乳味的中枢神经系统处理

新生儿在出生时就有一种功能性的嗅觉，这似乎对喂养和结合非常重要。尽管如此，对这个年龄段的大脑气味处理知之甚少。嗅觉功能的研究主要依赖于婴儿的行为、自主神经和面部反应。本研究的目的是调查婴儿的中枢气味处理，重点是脑电图 (EEG) 衍生的对具有生物学意义的气味（即食物和非食物气味）的反应。共有 21 名足月出生的健康婴儿参与（11 名男孩和 10 名女孩；年龄范围 2-9 个月，平均 5.3 ± 2.2 个月）。使用计算机控制的嗅觉计呈现气味刺激。母乳被用作食物气味。法尼醇以非食物气味的形式出现。此外，使用无味空气作为对照刺激物。每个刺激呈现 30 次，持续 1 秒，刺激间隔为 20 秒。从 9 个电极记录脑电图并在频域中进行分析。与对照条件和非食物气味（法呢醇）相比，呈现食物（母乳）气味后，δ 频带中的脑电图振幅显着不同。在正面记录位​​置观察到这些变化。本研究表明，婴儿的食物气味和非食物气味的中心气味处理不同。结果被解释为对生理相关气味（母乳）的关注，这表明嗅觉刺激在这个年龄组中具有特殊意义。与对照条件和非食物气味（法呢醇）相比，呈现食物（母乳）气味后，δ 频带中的脑电图振幅显着不同。在正面记录位​​置观察到这些变化。本研究表明，婴儿的食物气味和非食物气味的中心气味处理不同。结果被解释为对生理相关气味（母乳）的关注，这表明嗅觉刺激在这个年龄组中具有特殊意义。与对照条件和非食物气味（法呢醇）相比，呈现食物（母乳）气味后，δ 频带中的脑电图振幅显着不同。在正面记录位​​置观察到这些变化。本研究表明，婴儿的食物气味和非食物气味的中心气味处理不同。结果被解释为对生理相关气味（母乳）的关注，这表明嗅觉刺激在这个年龄组中具有特殊意义。本研究表明，婴儿的食物气味和非食物气味的中心气味处理不同。结果被解释为对生理相关气味（母乳）的关注，这表明嗅觉刺激在这个年龄组中具有特殊意义。本研究表明，婴儿的食物气味和非食物气味的中心气味处理不同。结果被解释为对生理相关气味（母乳）的关注，这表明嗅觉刺激在这个年龄组中具有特殊意义。