PNAS:植入人大脑基因的超级鼠变得更聪明
2014/09/17
科幻小说中,科学家一直热衷换头颅这项科研工作,但最近有科学家“实现”了这一工作,研究者通过将人类大脑一个负责语言表达的基因Foxp2植入到小鼠体内后发现,这些转基因工程鼠比普通鼠变得更加聪明。


在科幻小说中,科学家一直被视为热衷换头颅这项科研工作,因为它充满了挑战性。但最近研究通过将人类大脑一个负责语言表达的基因植入到小鼠体内,发现这些转基因工程鼠变得更加聪明。

小鼠植入的人类大脑基因Foxp2是用来负责人类语言表达的。早在2009年,科学家也进行过类似的实验,研究发现这些转基因工程鼠在植入了Foxp2基因后,脑部神经变得更加复杂,神经回路效率变得更高。从某种意义上说,小鼠变得更聪明了。

根据新华网介绍,美国麻省理工学院和欧洲几所大学的研究人员15日在美国《国家科学院学报》上报告说,他们首先培育出具有人类版本Foxp2的小鼠,然后让它们走T字迷宫寻找巧克力奶。一开始,培训小鼠进行有意识的学习,如平滑地面左转,粗糙地面右转等,小鼠做对了能得到奖赏,这种学习被称为叙述学习;经过长时间培训后,小鼠把这些记忆形成了无意识的习惯,这被称为程序学习。

研究人员利用交叉迷宫对小鼠进行测试,结果发现,如果仅一种学习方式参与,两种小鼠的表现没有明显差异。但当叙述学习和程序学习都参与时,拥有人类版本Foxp2基因的小鼠能比正常小鼠更迅速地找到奖赏,这说明这种基因能把小鼠的有意识叙述学习更快地转化成无意识程序学习。

50万年前,该基因发生突变从而使得人类获得语言表达的能力,这项研究主要是用来评估对不同物种“人源化大脑”的实验,是否有助于它们的认知。这也从另一个角度说明了这些基因在人类进化中所表现出的重要意义。

注:部分内容来自新华网

查看更多
  • Humanized Foxp2 accelerates learning by enhancing transitions from declarative to procedural performance

    The acquisition of language and speech is uniquely human, but how genetic changes might have adapted the nervous system to this capacity is not well understood. Two human-specific amino acid substitutions in the transcription factor forkhead box P2 (FOXP2) are outstanding mechanistic candidates, as they could have been positively selected during human evolution and as FOXP2 is the sole gene to date firmly linked to speech and language development. When these two substitutions are introduced into the endogenous Foxp2 gene of mice (Foxp2hum), cortico-basal ganglia circuits are specifically affected. Here we demonstrate marked effects of this humanization of Foxp2 on learning and striatal neuroplasticity. Foxp2hum/hum mice learn stimulus–response associations faster than their WT littermates in situations in which declarative (i.e., place-based) and procedural (i.e., response-based) forms of learning could compete during transitions toward proceduralization of action sequences. Striatal districts known to be differently related to these two modes of learning are affected differently in the Foxp2hum/hum mice, as judged by measures of dopamine levels, gene expression patterns, and synaptic plasticity, including an NMDA receptor-dependent form of long-term depression. These findings raise the possibility that the humanized Foxp2 phenotype reflects a different tuning of corticostriatal systems involved in declarative and procedural learning, a capacity potentially contributing to adapting the human brain for speech and language acquisition.

    展开 收起
发表评论 我在frontend\modules\comment\widgets\views\文件夹下面 test