Bayer S A
Department of Biology, Indiana-Purdue University, Indianapolis 46223.
Int J Dev Neurosci. 1986;4(3):251-71. doi: 10.1016/0736-5748(86)90063-8.
Neurogenesis in the rat primary olfactory cortex was examined with [3H]thymidine autoradiography. The experimental animals were the offspring of pregnant females given an injection of [3H]thymidine on two consecutive gestation days. Nine groups of embryos were exposed to [3H]thymidine on E13-E14, E14-E15....E21-E22, respectively. On P60, the percentage of labeled cells and the proportion of cells originating during 24 hr periods were quantified at selected anatomical levels of the anterior and posterior piriform cortex, dorsal lateral peduncular cortex, and posterior two-thirds of the ventral agranular insular cortex. Throughout most of the primary olfactory cortex, deep cells are generated earlier than superficial cells: the 'inside-out' pattern. Neurons in the anterior (prepiriform) cortex are located lateral to the caudal anterior olfactory nucleus and olfactory tubercle, and are generated mainly between E14 and E18 in a caudal (older) to rostral (younger) neurogenetic gradient. Neurons in the posterior (periamygdaloid) cortex are located lateral to the caudal olfactory tubercle and amygdala, and are generated mainly between E14 and E17 simultaneously along the rostrocaudal plane. Superficial cells in the piriform cortex have some additional neurogenetic gradients; ventromedial cells forming transition zones with either the olfactory tubercle or amygdala originate earlier than cells located dorsally and laterally. In the posterior piriform cortex, younger neurons are located at middle dorsoventral levels while older neurons lie above and below. Neurons in the dorsolateral peduncular cortex originate between E14 and E20 in a caudal to rostral gradient of neurogenesis; caudal parts also have a lateral to medial neurogenetic gradient. The most lateral part of the dorsolateral peduncular cortex is unique and does not have the typical 'inside-out' cortical neurogenetic gradient. Neurons in the ventral agranular insular cortex (area 13) originate mainly between E15 and E17 in combined caudal to rostral and ventral to dorsal neurogenetic gradients. The neurogenetic gradients in the primary olfactory cortex, along with patterns of neurogenesis throughout the olfactory projection field are related to the termination patterns of afferents from the main olfactory bulb.
采用[3H]胸腺嘧啶核苷放射自显影术研究大鼠初级嗅觉皮层中的神经发生。实验动物为连续两天接受[3H]胸腺嘧啶核苷注射的怀孕雌性大鼠的后代。将九组胚胎分别在胚胎期第13 - 14天、第14 - 15天……第21 - 22天暴露于[3H]胸腺嘧啶核苷。在出生后第60天，在梨状前皮质和梨状后皮质、背外侧脚状核皮质以及腹侧无颗粒岛叶皮质后三分之二的选定解剖层面，对标记细胞的百分比以及24小时内产生的细胞比例进行定量分析。在大部分初级嗅觉皮层中，深层细胞比浅层细胞产生得早，即“由内向外”模式。前（梨状前）皮质中的神经元位于尾侧前嗅核和嗅结节的外侧，主要在胚胎期第14天至第18天之间产生，呈尾侧（较老）至头侧（较年轻）的神经发生梯度。后（杏仁周）皮质中的神经元位于尾侧嗅结节和杏仁核的外侧，主要在胚胎期第14天至第17天之间沿头尾平面同时产生。梨状皮质中的浅层细胞有一些额外的神经发生梯度；与嗅结节或杏仁核形成过渡区的腹内侧细胞比背侧和外侧的细胞产生得早。在梨状后皮质中，较年轻的神经元位于背腹中部水平，而较老的神经元位于其上方和下方。背外侧脚状核皮质中的神经元在胚胎期第14天至第20天之间产生，呈尾侧到头侧的神经发生梯度；尾侧部分也有从外侧到内侧的神经发生梯度。背外侧脚状核皮质的最外侧部分是独特的，不具有典型的“由内向外”皮质神经发生梯度。腹侧无颗粒岛叶皮质（13区）中的神经元主要在胚胎期第15天至第17天之间产生，呈尾侧到头侧和腹侧到背侧的联合神经发生梯度。初级嗅觉皮层中的神经发生梯度，以及整个嗅觉投射区域的神经发生模式，与来自主嗅球的传入纤维的终止模式有关。
