Dark J, Dark K A, Zucker I
Brain Res. 1987 Apr 21;409(2):302-7. doi: 10.1016/0006-8993(87)90715-3.
Male voles reared in long (spring) day lengths had heavier brains with greater total DNA content than did males housed in short (fall) day lengths; these effects were not observed in female littermates kept in the two photoperiods. Male brains were heavier than female brains in long but not in short photoperiods. Day length affected brain mass during early postnatal development, but not when treatments were initiated in adulthood. Seasonal differences in brain development, including the numbers of neurons and glia, may reflect different metabolic and behavioral demands faced by males born in spring and fall, respectively.
在长（春季）日照时长环境下饲养的雄性田鼠，其大脑比在短（秋季）日照时长环境下饲养的雄性田鼠更重，总DNA含量也更高；而处于这两种光周期环境下的雌性同窝幼崽则未观察到这些影响。在长日照而非短日照光周期环境下，雄性大脑比雌性大脑更重。日照时长在出生后早期发育阶段会影响脑质量，但在成年期开始进行处理时则不会。大脑发育的季节性差异，包括神经元和神经胶质细胞的数量，可能分别反映了春季和秋季出生的雄性田鼠所面临的不同代谢和行为需求。
