【正确答案】研究人员对320名年龄在66岁到90岁的身体健康的男子和女子的脑部扫描 X光片研究后发现，受试者的受教育经历每多一年，其大脑外层叫做脑皮层的部位就多一份萎缩。

【答案解析】[结构分析] 句子框架是Examining brain scans...，researchers found that...there was greater shrink age of the outer layer of the brain known as the cortex(脑皮层)。examining...是现在分词结构作时间状语，that引导宾语从句。此从句是个there be句型；the subjects had作为定语从句修饰education；known as the cortex作定语，修饰the outer layer of the brain。