McIntosh Anthony Randal, Kovacevic Natasa, Itier Roxane J
Rotman Research Institute of Baycrest Centre, University of Toronto, Toronto, Ontario, Canada.
PLoS Comput Biol. 2008 Jul 4;4(7):e1000106. doi: 10.1371/journal.pcbi.1000106.
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.
随着大脑的成熟，其反应会变得更加优化。行为测量通过提高准确性和减少试验间的变异性来体现这一点。问题仍然是，支持大脑活动的动力学是否也表现出类似的变异性降低。我们研究了儿童（8 - 15岁）和年轻成年人（20 - 33岁）单次试验诱发的脑电活动（通过脑电图测量）的变异性与面部记忆任务表现之间的关系。在行为方面，儿童的反应时间比成年人更慢、变异性更大，识别准确性也更低。然而，脑信号变异性随年龄增加，并且与个体内反应时间变异性呈强烈负相关，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。这种变异性可能反映了更广泛的亚稳态脑状态库以及它们之间更灵活的转换，从而实现最佳反应。我们的结果表明，大脑活动的瞬间变异性可能是大脑认知能力的关键指标。
