Sambeth Anke, Huotilainen Minna, Kushnerenko Elena, Fellman Vineta, Pihko Elina
Cognitive Brain Research Unit, Department of Psychology, University of Helsinki, P.O. Box 9, FIN-00014 Helsinki, Finland.
Clin Neurophysiol. 2006 Mar;117(3):496-503. doi: 10.1016/j.clinph.2005.11.008. Epub 2006 Jan 19.
We investigated whether newborns respond differently to novel and deviant sounds during quiet sleep.
Twelve healthy neonates were presented with a three-stimulus oddball paradigm, consisting of frequent standard (76%), infrequent deviant (12%), and infrequent novel stimuli (12%). The standards and deviants were counterbalanced between the newborns and consisted of 500 and 750 Hz tones with two upper harmonics. The novel stimuli contained animal, human, and mechanical sounds. All stimuli had a duration of 300 ms and the stimulus onset asynchrony was 1s. Evoked magnetic responses during quiet sleep were recorded and averaged offline.
Two deflections peaking at 345 and 615 ms after stimulus onset were observed in the evoked responses of most of the newborns. The first deflection was larger to novel and deviant stimuli than to the standard and, furthermore, larger to novel than to deviant stimuli. The second deflection was larger to novel and deviant stimuli than to standards, but did not differ between the novels and deviants.
The two deflections found in the present study reflect different mechanisms of auditory change detection and discriminative processes.
The early brain indicators of novelty detection may be crucial in assessing the normal and abnormal cortical function in newborns. Further, studying evoked magnetic fields to complex auditory stimulation in healthy newborns is needed for studying the newborns at-risk for cognitive or language problems.
我们研究了新生儿在安静睡眠期间对新奇声音和异常声音的反应是否不同。
对12名健康新生儿采用三刺激Oddball范式，包括频繁出现的标准刺激（76%）、不频繁出现的异常刺激（12%）和不频繁出现的新奇刺激（12%）。标准刺激和异常刺激在新生儿之间进行了平衡，由500和750赫兹的音调以及两个高次谐波组成。新奇刺激包含动物、人类和机械声音。所有刺激的持续时间为300毫秒，刺激起始异步时间为1秒。在安静睡眠期间记录诱发磁反应并进行离线平均。
在大多数新生儿的诱发反应中观察到两个在刺激开始后345和615毫秒达到峰值的偏转。第一个偏转对新奇刺激和异常刺激的反应比对标准刺激的反应更大，而且对新奇刺激的反应比对异常刺激的反应更大。第二个偏转对新奇刺激和异常刺激的反应比对标准刺激的反应更大，但在新奇刺激和异常刺激之间没有差异。
本研究中发现的两个偏转反映了听觉变化检测和辨别过程的不同机制。
新奇检测的早期脑指标可能对评估新生儿的正常和异常皮质功能至关重要。此外，为了研究有认知或语言问题风险的新生儿，需要研究健康新生儿对复杂听觉刺激的诱发磁场。
