Department of Anatomy and Neurobiology, Central South University, Xiangya School of Medicine, Changsha, Hunan, China.
Anat Rec (Hoboken). 2013 Jan;296(1):123-32. doi: 10.1002/ar.22616. Epub 2012 Nov 14.
The CA3 area serves a key relay on the tri-synaptic loop of the hippocampal formation which supports multiple forms of mnemonic processing, especially spatial learning and memory. To date, morphometric data about human CA3 pyramidal neurons are relatively rare, with little information available for their pre- and postnatal development. Herein, we report a set of developmental trajectory data, including somal growth, dendritic elongation and branching, and spine formation, of human CA3 pyramidal neurons from midgestation stage to middle childhood. Golgi-impregnated CA3 pyramidal neurons in fetuses at 19, 20, 26, 35, and 38 weeks of gestation (GW) and a child at 8 years of age (Y) were analyzed by Neurolucida morphometry. Somal size of the impregnated CA3 cells increased age-dependently among the cases. The length of the apical and basal dendrites of these neurons increased between 26 GW to 38 GW, and appeared to remain stable afterward until 8 Y. Dendritic branching points increased from 26 GW to 38 GW, with that on the apical dendrites slightly reduced at 8 Y. Spine density on the apical and basal dendrites increased progressively from 26 GW to 8 Y. These data suggest that somal growth and dendritic arborization of human CA3 pyramidal neurons occur largely during the second to third trimester. Spine development and likely synaptogenesis on CA3 pyramidal cells progress during the third prenatal trimester and may continue throughout childhood.
CA3 区是海马结构三突触环的关键中继站，支持多种记忆处理形式，特别是空间学习和记忆。迄今为止，关于人类 CA3 锥体神经元的形态计量学数据相对较少，其产前和产后发育的信息很少。在此，我们报告了一组人类 CA3 锥体神经元的发育轨迹数据，包括从中孕期到儿童中期的体生长、树突伸长和分支以及棘突形成。通过 Neurolucida 形态计量学分析了 19、20、26、35 和 38 孕周（GW）的胎儿和 8 岁儿童的高尔基浸渍 CA3 锥体神经元。浸渍的 CA3 细胞的体大小在这些病例中随年龄增长而增加。这些神经元的顶树突和底树突的长度在 26 GW 到 38 GW 之间增加，并在此后似乎保持稳定，直到 8 岁。树突分支点从 26 GW 增加到 38 GW，8 岁时顶树突上的分支点略有减少。顶树突和底树突上的棘突密度从 26 GW 到 8 岁逐渐增加。这些数据表明，人类 CA3 锥体神经元的体生长和树突分支主要发生在第二至第三个三个月。CA3 锥体细胞上的棘突发育和可能的突触发生在第三个产前三个月进行，并可能持续到整个儿童期。
