EEG gamma-band synchronization in visual coding from childhood to old age: Evidence from evoked power and inter-trial phase locking
EEG gamma-band synchronization in visual coding from childhood to old age: Evidence from evoked power and inter-trial phase locking
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DOI：
10.1016/j.clinph.2009.04.012
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发表时间：
2009-07
影响因子：
4.7
通讯作者：
M. Werkle-Bergner;Y. Shing;Viktor Müller;Shu-Chen Li;U. Lindenberger
中科院分区：
文献类型：
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作者：
M. Werkle-Bergner;Y. Shing;Viktor Müller;Shu-Chen Li;U. Lindenberger
方法：在一个简单的选择反应任务中，记录17名儿童（10- 12岁）、16名青年（20- 26岁）和17名老年人（70- 76岁）的EEG，该任务要求辨别不同大小的正方形和圆形。我们研究了刺激大小对早期ERP成分的影响的年龄组差异，诱发的γ-波段功率，以及由锁相指数（PLI）评估的γ-波段的试验间相位稳定性。儿童P1、N1峰振幅大于成人，峰潜伏期长于成人。儿童的诱发功率和PLI水平也低于成人。老年人表现出较小的增量，在诱发功率与刺激大小的增加比年轻的成年人，但类似的金额的相位锁定为小型和中型的刺激作为年轻adults. CONCLUSIONSSThe不同的编码机制的相对重要性，在早期视觉领域的变化，从童年到老年。由于突触过度产生和髓鞘形成不成熟，儿童的视觉系统较少受到传入信息的干扰，导致神经元反应不同步。成年人主要依赖于通过经验依赖性时间同步神经元相互作用形成的稀疏表示。在老年，衰老的神经元密度和神经递质的可用性下降进一步增加依赖于时间同步processing.SIGNIFICANCEFindings从这项研究中挑战的概念，即感觉老化包括在一个逆转的感觉发展在儿童时期，并指出一个高度的年龄特异性的视觉编码机制。
OBJECTIVETo investigate lifespan age differences in neuronal mechanisms of visual coding in the context of perceptual discrimination.METHODSWe recorded EEG from 17 children (10–12years), 16 younger adults (20–26years), and 17 older adults (70–76years) during a simple choice-reaction task requiring discrimination of squares and circles of different sizes. We examined age-group differences in the effect of stimulus size on early ERP components, evoked gamma-band power, and inter-trial phase-stability in the gamma band as assessed by the phase-locking index (PLI).RESULTSIn the absence of age differences in discrimination accuracy, we observed reliable age differences in patterns of ERP, evoked gamma power, and PLI. P1 and N1 peak amplitudes were larger and the peak latencies longer in children than in adults. Children also showed lower levels of evoked power and PLI than adults. Older adults showed smaller increments in evoked power with increasing stimulus size than younger adults, but similar amounts of phase locking for small- and medium-sized stimuli as younger adults.CONCLUSIONSThe relative importance of different coding mechanisms in early visual areas changes from childhood to old age. Due to synaptic overproduction and immature myelination, the visual system of children is less entrained by incoming information, resulting in less synchronized neuronal responses. Adults primarily rely on sparse representations formed through experience-dependent temporally synchronized neuronal interactions. In old age, senescent decline in neuronal density and neurotransmitter availability further increase the reliance on temporally synchronized processing.SIGNIFICANCEFindings from this study defy the notion that sensory aging consists in a reversal of sensory development in childhood, and point to a high degree of age specificity in mechanisms of visual coding.