Relative percentage of Sox5 positive cells in the different layers of the caudal cortex at E20.

Average number of cells per animal and region are expressed between brackets.Data are mean ± SEM, versus control group.各动物及各区域的平均细胞数以括号形式标注。数据以平均值±标准误（Standard Error of the Mean，SEM）表示，并与对照组进行比较。