Contraction of front and side parts as cells die off was observed in some subjects in their thirties， but it was still not evident in some sixty and seventy-year-olds.

有的人(大脑)前部和侧部的收缩——随着细胞的死亡——在三十多岁时就能被观察到了，但是也有些人直到六七岁依然不明显。