Başar-Eroglu C, Kolev V, Ritter B, Aksu F, Başar E
Institute of Physiology, Medical University Lübeck, Lübeck, Germany.
Int J Neurosci. 1994 Apr;75(3-4):239-55. doi: 10.3109/00207459408986307.
According to our working hypothesis, the resonance properties of the brain systems play an important role in internal brain communications (e.g., Başar, 1992; Başar, Başar-Eroglu, Demiralp & Schürmann, 1992). It was assumed that evoked potentials (EPs) reflect brain resonance properties, showing enhancement, time and frequency-locking during the poststimulus period. All these phenomena might be referred to the spontaneous (intrinsic) EEG rhythms according to the excitability rule and the related concept of brain system response susceptibility: a brain system could react to internal or external stimuli producing those rhythms or frequency components, which have already been present in intrinsic or spontaneous activity (Başar, 1980). In order to test the hypothesis of response susceptibility, in the present paper we used an natural model--3-year-old children--to investigate how brain systems respond to external stimulation if their spontaneous rhythms are different in comparison to the spontaneous EEG rhythms in adults. For that purpose we used a combined time and frequency domain approach. The spectral characteristics of the spontaneous EEGs as well as the frequency components of auditory EPs elicited under identical auditory stimulation in 3-year-old children and adults aged 20-22 years were compared. Our observations support the hypothesis for response susceptibility; if in a given frequency channel the spontaneous brain rhythms are missing, they are also absent in the evoked and induced rhythmicities and vice versa: children at 3 years do not create alpha resonance upon sensory stimulation while they do not have developed EEG rhythms in the range of 8-15 Hz. Elicited under identical experimental conditions (auditory stimulation with fixed stimulus parameters) children and adult evoked rhythms differ. It was concluded that the AEPs recorded in 3-year-old children might be regarded mainly as a superposition of rhythmicities in delta and theta ranges. These rhythmicities are prolonged and delayed in comparison to the corresponding rhythms in adults.
根据我们的工作假设，大脑系统的共振特性在大脑内部通讯中起着重要作用（例如，巴萨尔，1992年；巴萨尔、巴萨尔-埃罗格鲁、德米拉普和舒尔曼，1992年）。据推测，诱发电位（EPs）反映了大脑的共振特性，在刺激后时期表现出增强、时间和频率锁定。根据兴奋性规则以及大脑系统反应敏感性的相关概念，所有这些现象可能都与自发（内在）脑电图节律有关：大脑系统可以对产生那些已经存在于内在或自发活动中的节律或频率成分的内部或外部刺激做出反应（巴萨尔，1980年）。为了检验反应敏感性的假设，在本文中我们使用了一个自然模型——3岁儿童——来研究如果他们的自发节律与成年人的自发脑电图节律不同，大脑系统对外部刺激的反应方式。为此我们采用了时域和频域相结合的方法。比较了3岁儿童和20 - 22岁成年人在相同听觉刺激下自发脑电图的频谱特征以及听觉诱发电位的频率成分。我们的观察结果支持反应敏感性的假设；如果在给定的频率通道中自发脑节律缺失，那么在诱发和诱导的节律中也会缺失，反之亦然：3岁儿童在感觉刺激时不会产生α共振，因为他们在8 - 15赫兹范围内还没有发育出脑电图节律。在相同的实验条件下（固定刺激参数的听觉刺激），儿童和成年人诱发的节律有所不同。得出的结论是，3岁儿童记录的听觉诱发电位可能主要被视为δ波和θ波范围内节律的叠加。与成年人相应的节律相比，这些节律持续时间更长且延迟。
