Edin Fredrik, Macoveanu Julian, Olesen Pernille, Tegnér Jesper, Klingberg Torkel
Karolinska Institutet, Stockholm, Sweden.
J Cogn Neurosci. 2007 May;19(5):750-60. doi: 10.1162/jocn.2007.19.5.750.
The cellular maturational processes behind cognitive development during childhood, including the development of working memory capacity, are still unknown. By using the most standard computational model of visuospatial working memory, we investigated the consequences of cellular maturational processes, including myelination, synaptic strengthening, and synaptic pruning, on working memory-related brain activity and performance. We implemented five structural developmental changes occurring as a result of the cellular maturational processes in the biophysically based computational network model. The developmental changes in memory activity predicted from the simulations of the model were then compared to brain activity measured with functional magnetic resonance imaging in children and adults. We found that networks with stronger fronto-parietal synaptic connectivity between cells coding for similar stimuli, but not those with faster conduction, stronger connectivity within a region, or increased coding specificity, predict measured developmental increases in both working memory-related brain activity and in correlations of activity between regions. Stronger fronto-parietal synaptic connectivity between cells coding for similar stimuli was thus the only developmental process that accounted for the observed changes in brain activity associated with development of working memory during childhood.
童年时期认知发展背后的细胞成熟过程，包括工作记忆能力的发展，目前仍不清楚。通过使用最标准的视觉空间工作记忆计算模型，我们研究了细胞成熟过程（包括髓鞘形成、突触强化和突触修剪）对与工作记忆相关的大脑活动和表现的影响。我们在基于生物物理学的计算网络模型中实施了因细胞成熟过程而发生的五种结构发育变化。然后将从模型模拟中预测的记忆活动的发育变化与儿童和成人功能性磁共振成像测量的大脑活动进行比较。我们发现，在编码相似刺激的细胞之间具有更强额顶叶突触连接的网络，而不是那些传导速度更快、区域内连接更强或编码特异性增加的网络，预测了与工作记忆相关的大脑活动以及区域间活动相关性的测量发育增加。因此，编码相似刺激的细胞之间更强的额顶叶突触连接是唯一能够解释童年时期与工作记忆发展相关的大脑活动观察到的变化的发育过程。
