Female rats learn trace memories better than male rats and consequently retain a greater proportion of new neurons in their hippocampi
Female rats learn trace memories better than male rats and consequently retain a greater proportion of new neurons in their hippocampi
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DOI：
10.1073/pnas.0809650106
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发表时间：
2009-02-24
影响因子：
11.1
通讯作者：
Shors, Tracey J.
中科院分区：
文献类型：
--
作者：
Dalla, Christina;Papachristos, Efstathios B.;Shors, Tracey J.
学习增加了在训练经历之前在海马结构中产生的新细胞的存活，特别是如果动物学习跨时间关联刺激[Gould E，Beylin A，Tanapat P，Reeves A，Shors TJ（1999）Nat Neurosci 2：260-265]。所有相关研究都是在雄性大鼠身上进行的，尽管有证据表明这种学习方式存在性别差异。在本研究中，我们询问学习中的性别差异是否会影响成年海马中产生的神经元的存活。雄性和雌性成年大鼠注射一剂溴脱氧尿苷（BrdU; 200 mg/kg），以标记一个分裂细胞群。一周后，一半的动物接受了跟踪眨眼条件反射的时间学习任务的训练，而另一半则没有接受训练。训练后1天（注射BrdU后12天）处死动物。对海马组织进行BrdU和未成熟神经元的标记物doublecortin染色。两性都学会了在跟踪间隔期间发出条件眨眼反应。结果，与性别匹配的对照组相比，更多的新神经元留在了他们的前腹。在个体动物中，存活细胞的数量与渐近表现呈正相关;那些表达更多学习反应的细胞保留了更多的新神经元。然而，学习能力很强的动物在需要多次试验的情况下会保留更多的新细胞。由于雌性比雄性发出更多的学习反应，它们在每单位体积的组织中保留了近两倍的新细胞。这种效应在海马结构的腹侧区域最为明显。因此，学习中的性别差异改变了海马体的解剖结构。因此，男性和女性的大脑在成年后继续分化。
Learning increases the survival of new cells that are generated in the hippocampal formation before the training experience, especially if the animal learns to associate stimuli across time [Gould E, Beylin A, Tanapat P, Reeves A, Shors TJ (1999) Nat Neurosci 2: 260-265]. All relevant studies have been conducted on male rats, despite evidence for sex differences in this type of learning. In the present study, we asked whether sex differences in learning influence the survival of neurons generated in the adult hippocampus. Male and female adult rats were injected with one dose of bromodeoxyuridine (BrdU; 200 mg/kg), to label one population of dividing cells. One week later, half of the animals were trained with a temporal learning task of trace eyeblink conditioning, while the other half were not trained. Animals were killed 1 day after training (12 days after the BrdU injection). Hippocampal tissue was stained for BrdU and a marker of immature neurons, doublecortin. Both sexes learned to emit the conditioned eyeblink response during the trace interval. As a consequence, more new neurons remained in their hippocampi than in sex-matched controls. In individual animals, the number of surviving cells correlated positively with asymptotic performance; those that expressed more learned responses retained more new neurons. However, animals that learned very well retained even more new cells if they required many trials to do so. Because females emitted more learned responses than males did, they retained nearly twice as many new cells per unit volume of tissue. This effect was most evident in the ventral region of the hippocampal formation. Thus, sex differences in learning alter the anatomical structure of the hippocampus. As a result, male and female brains continue to differentiate in adulthood.