Afonso D, Santana C, Rodriguez M
Laboratory of Behavioral Neurochemistry, School of Medicine, University of La Laguna, Tenerife, Canary Islands, Spain.
Brain Res Bull. 1993;32(1):11-6. doi: 10.1016/0361-9230(93)90312-y.
Behavioral lateralization has previously been reported in adult animals. This work presents a study of behavioral laterality and spontaneous alternation behavior in 156 neonatal rats (39 litters with two males and two females per litter). The initial tail and head lateral movements (axis body-tail or head higher than 30 degrees) were recorded after neonatal rats were gently placed along a straight line drawn on a glass surface. This test was repeated 10 times. A leftward population lateralization was found for tail movement while head movement was rightward. The alternation behavior was lower (10-25%) than that previously reported for adult rats (80-90%) and than that expected if movement was made at random (50%). Males were more lateralized than females for head and tail movements. No sex differences were observed for behavioral alternation. In 2-day-old rats (10 litters with one male and one female per litter), the right brain side had a higher content in dopamine (mesencephalon) and DOPAC (proencephalon) than the left brain side. Thus, we concluded that behavioral and biochemical asymmetries in animals are conditioned by phenomena present during prenatal or early neonatal (first hours after birth) life and that spontaneous alternation behavior is not present during the earlier stages of postnatal development.
此前已有报道称成年动物存在行为偏侧化。这项研究对156只新生大鼠（39窝，每窝两只雄性和两只雌性）的行为偏侧性和自发交替行为进行了研究。将新生大鼠轻轻放置在玻璃表面绘制的直线上后，记录其最初的尾巴和头部侧向运动（身体 - 尾巴轴线或头部高于30度）。该测试重复进行10次。发现尾巴运动存在向左的群体偏侧化，而头部运动则向右。交替行为（10 - 25%）低于先前报道的成年大鼠（80 - 90%）以及随机运动时预期的比例（50%）。在头部和尾巴运动方面，雄性比雌性的偏侧化程度更高。在行为交替方面未观察到性别差异。在2日龄大鼠（10窝，每窝一只雄性和一只雌性）中，右脑一侧（中脑）的多巴胺和前脑的3,4-二羟基苯乙酸含量高于左脑一侧。因此，我们得出结论，动物的行为和生化不对称是由产前或新生儿早期（出生后最初几小时）出现的现象所决定的，并且在出生后发育的早期阶段不存在自发交替行为。
