Increased brain signal variability accompanies lower behavioral variability in development.
Increased brain signal variability accompanies lower behavioral variability in development.
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DOI：
10.1371/journal.pcbi.1000106
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发表时间：
2008-07-04
影响因子：
4.3
通讯作者：
Itier RJ
中科院分区：
文献类型：
--
作者：
McIntosh AR;Kovacevic N;Itier RJ
随着大脑的成熟，它的反应变得最优。行为测量通过提高准确性和减少试验间的可变性来证明这一点。问题仍然是，支持的大脑动力学是否显示出类似的可变性减少。我们研究了儿童（8-15岁）和年轻人（20-33岁）的单试验诱发脑电活动变异性（用脑电图测量）与面部记忆任务表现之间的关系。在行为上，儿童表现出比成年人更慢、更多变的反应时间（RT）和更低的识别准确性。然而，大脑信号变异性随着年龄的增长而增加，并与受试者内部RT变异性呈强烈的负相关，与准确性呈正相关。因此，成熟似乎导致大脑具有更大的功能变异性，这表明神经复杂性增强。这种可变性可能反映了更广泛的亚稳态脑状态，以及它们之间更流畅的转换，从而实现最佳反应。我们的研究结果表明，大脑活动的瞬间变化可能是大脑认知能力的一个关键指标。大脑-行为关系的直觉概念表明，由于儿童在行为上表现出更多的可变性，他们的大脑也应该更加多变。我们证明情况并非如此。在用脑电图测量大脑信号变异性和在一个简单的面部识别任务中的行为时，我们发现8-15岁儿童的大脑信号变异性增加，而年轻人的大脑信号变异性更高。重要的是，我们表明这种增加的大脑变异性与减少的行为变异性和更准确的表现相关。具有更多可变性的大脑也具有更大的复杂性和更大的信息处理能力。我们的研究结果表明，大脑信号的可变性，或者一些人所说的噪音，实际上是大脑功能的一个关键特征。为了使大脑在最佳水平上运行，一定数量的内部噪音是必要的。从某种程度上说，嘈杂的大脑是健康的大脑。
As the brain matures, its responses become optimized. Behavioral measures show this through improved accuracy and decreased trial-to-trial variability. The question remains whether the supporting brain dynamics show a similar decrease in variability. We examined the relation between variability in single trial evoked electrical activity of the brain (measured with EEG) and performance of a face memory task in children (8–15 y) and young adults (20–33 y). Behaviorally, children showed slower, more variable response times (RT), and less accurate recognition than adults. However, brain signal variability increased with age, and showed strong negative correlations with intrasubject RT variability and positive correlations with accuracy. Thus, maturation appears to lead to a brain with greater functional variability, which is indicative of enhanced neural complexity. This variability may reflect a broader repertoire of metastable brain states and more fluid transitions among them that enable optimum responses. Our results suggest that the moment-to-moment variability in brain activity may be a critical index of the cognitive capacity of the brain. Intuitive notions of brain–behavior relationships would suggest that because children show more variability in behavior, their brains should also be more variable. We demonstrate that this is not the case. In measuring brain signal variability with EEG and behavior in a simple face recognition task, we found that brain signal variability increases in children from 8–15 y and is even higher in young adults. Importantly, we show that this increased brain variability correlates with reduced behavioral variability and more accurate performance. A brain that has more variability also has greater complexity and a greater capacity for information processing. The implication of our findings is that variability in brain signals, or what some would call noise, is actually a critical feature of brain function. For the brain to operate at an optimal level, a certain amount of internal noise is necessary. In a certain way it could be stated that a noisy brain is a healthy brain.
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DOI：
10.1073/pnas.0504136102
发表时间：
2005-07-05
影响因子：
11.1
作者：
Fox, MD;Snyder, AZ;Raichle, ME
通讯作者：
Raichle, ME
影响因子：
3.7
作者：
Itier, RJ;Taylor, MJ
通讯作者：
Taylor, MJ
影响因子：
64.8
作者：
DOUGLASS, JK;WILKENS, L;MOSS, F
通讯作者：
MOSS, F
影响因子：
2.6
作者：
Balázsi, G;Kish, LB
通讯作者：
Kish, LB
影响因子：
5.7
作者：
Friston, KJ
通讯作者：
Friston, KJ