Jacobs L F, Gaulin S J, Sherry D F, Hoffman G E
Department of Anthropology, University of Pittsburgh, PA 15260.
Proc Natl Acad Sci U S A. 1990 Aug;87(16):6349-52. doi: 10.1073/pnas.87.16.6349.
In a study of two congeneric rodent species, sex differences in hippocampal size were predicted by sex-specific patterns of spatial cognition. Hippocampal size is known to correlate positively with maze performance in laboratory mouse strains and with selective pressure for spatial memory among passerine bird species. In polygamous vole species (Rodentia: Microtus), males range more widely than females in the field and perform better on laboratory measures of spatial ability; both of these differences are absent in monogamous vole species. Ten females and males were taken from natural populations of two vole species, the polygamous meadow vole, M. pennsylvanicus, and the monogamous pine vole, M. pinetorum. Only in the polygamous species do males have larger hippocampi relative to the entire brain than do females. Two-way analysis of variance shows that the ratio of hippocampal volume to brain volume is differently related to sex in these two species. To our knowledge, no previous studies of hippocampal size have linked both evolutionary and psychometric data to hippocampal dimensions. Our controlled comparison suggests that evolution can produce adaptive sex differences in behavior and its neural substrate.
在一项对两种同属啮齿动物的研究中，海马体大小的性别差异是由空间认知的性别特异性模式预测的。已知海马体大小与实验室小鼠品系的迷宫表现以及雀形目鸟类物种中空间记忆的选择压力呈正相关。在一夫多妻制的田鼠物种（啮齿目：田鼠属）中，雄性在野外的活动范围比雌性更广，并且在空间能力的实验室测试中表现更好；而在一夫一妻制的田鼠物种中，这两种差异都不存在。从两种田鼠物种的自然种群中选取了10只雌性和10只雄性，分别是一夫多妻制的草甸田鼠（M. pennsylvanicus）和一夫一妻制的松田鼠（M. pinetorum）。只有在一夫多妻制的物种中，雄性相对于整个大脑的海马体比雌性更大。双向方差分析表明，这两个物种中海马体体积与大脑体积的比率与性别的关系不同。据我们所知，以前没有关于海马体大小的研究将进化数据和心理测量数据与海马体维度联系起来。我们进行的对照比较表明，进化可以在行为及其神经基础上产生适应性的性别差异。
