Bruno J P, Snyder A M, Stricker E M
Behav Neurosci. 1984 Feb;98(1):156-61. doi: 10.1037//0735-7044.98.1.156.
Rats given large dopamine-depleting brain lesions as adults exhibit severe impairments in ingestive behavior and sensorimotor function. In contrast to these well-known effects, virtually complete destruction of central dopaminergic neurons produced no such dysfunctions when it occurred in neonates. Indeed, rats continued to suckle and grow, albeit somewhat more slowly, and they could be weaned readily when they were 27 days old. Although most brain-damaged animals did not survive weaning when they were 18 days old, whereas controls exhibited no difficulty, this failure appears to be the consequence of their reduced body weight and related inability to maintain body temperature in a relatively cool environment (22 degrees C). Such premature weaning occurred more successfully when growth was stimulated by rearing brain-damaged pups in small litters or when ambient temperatures were raised to 31 degrees C so as to minimize heat loss. These results demonstrate that the effects of near-total dopamine-depleting brain lesions are considerably less severe when they occur in infants than when they occur in adults, and, consequently, they reveal a capacity for neural plasticity during development that is no longer present at maturity.
成年大鼠若脑部出现大量消耗多巴胺的损伤，其摄食行为和感觉运动功能会出现严重障碍。与这些众所周知的影响形成对比的是，若中枢多巴胺能神经元在新生大鼠中几乎完全被破坏，却不会产生此类功能障碍。实际上，大鼠仍能继续吮乳并生长，尽管速度稍慢一些，且在27日龄时能够顺利断奶。虽然大多数脑部受损的动物在18日龄时断奶未能存活，而对照组则没有困难，但这种失败似乎是由于它们体重减轻以及在相对凉爽的环境（22摄氏度）中无法维持体温所致。当通过将脑部受损的幼崽饲养在小窝中刺激生长，或者将环境温度提高到31摄氏度以尽量减少热量损失时，这种过早断奶会更成功。这些结果表明，几乎完全消耗多巴胺的脑部损伤在婴儿期发生时的影响远不如在成年期发生时严重，因此，它们揭示了发育过程中神经可塑性的能力，而这种能力在成熟后便不再存在。
