神经元负责让触摸感到愉快

  • 发表10月10日11月10日
  • 作者Calli McMurray
  • 资源BrainFacts/SfN
Colorful hands touching
照片由Cottonbro在pexels上

小鼠脊髓中的一小群神经元可能使与触摸相关的令人愉悦,有益的感受。没有这些神经元的小鼠变得更容易受到压力的负面影响。研究人员在11月2日与神经科学协会年会联系的新闻发布会上尚未进行同行评审。万博体育登录手机版

我们wellbein触觉深刻的影响g. A hug from a loved one can ease the toil of a hard day, and a rub on the back soothes an upset child. “But we don't actually know how touch is experienced as pleasant,” said Melanie Schaffler, a graduate student at the Zuckerman Institute at Columbia University. “Why is a back rub different from sitting back in your chair? Both are touch sensations on your back, but they have a different emotional quality.”

答案在于在与大脑中连接神经元的电路中的某处。在外周神经系统中的神经元终止于皮肤的不同层,具有各种形状和尺寸的受体。有些人检测到痒;其他振动,压力或疼痛。这些受体从皮肤开始从皮肤到脊髓内的神经细胞体的继电器。然后,信号行进到发生意识的感知的大脑。“我们不知道这连胜在哪里,我们得到了”漂亮“的感觉,”Schaffler说。“它是否从皮肤开始?”

脑,脊髓和皮肤
在到达大脑之前,触摸感觉从皮肤的受体到脊髓中的细胞体。
Melanie Schaffler。使用Biorender创建

答案可以是一种在背根神经节中发现的一种感觉神经元,脊髓中的一群神经元。在小鼠中激活这些神经元导致快乐和奖励的感受。与背根神经节中的其他神经元不同,这些表达称为MRGPRB4的基因。只有两种背根神经节神经元的百分之只为此而这样做。

Schaffler和她的实验室伴侣阻断了表达MRGPRB4基因的神经元,因此所有细胞都在小鼠4天之前死亡。尽管小鼠在正常的社会环境中长大并具有完整的触感,但它们也无法察觉触感的有益方面。

作为成年人,小鼠的表现形式与焦虑和抑郁症阵列中的对照相同;只有一旦老鼠经历了压力,才会出现差异。

After three days of stress, the mice missing MrgprB4 neurons showed increased depression-like behaviors, including decreased grooming. Growing up without the ability to experience the rewarding aspects of touch may make mice more vulnerable to negative consequences from stress. The next round of research will investigate if activating these neurons makes mice more resilient to stress.

“这[研究]正在向前迈出一步,”弗朗西斯·麦格隆(Riverpole John Moores University)的神经科学领袖和神经科学教授说。但工作尚未结束。“我们真正等待的是[在人类]的翻译证据。”

人类中相同类型神经元的主要竞争者是一群称为C-触觉交流的感觉神经。这类神经纤维仅响应轻柔的触摸。问题是,他们不容易研究。“我们不知道他们在哪里,”麦格隆说。“我们对他们没有标记,[所以]我们不能为他们染色并识别他们实际终止于皮肤的地方。”此外,触摸和疼痛的动物模型有没有直接翻译给人类的历史。

Locating and studying these neurons in humans could usher in an era of depression treatments targeting the peripheral nervous system, rather than the brain itself. Current antidepressants offer relief along with a slew of side effects and can take weeks to start working. “Maybe it's time to start looking elsewhere,” Schaffler said.

Activating the right neurons in the skin could also provide the crucial benefits of a soothing touch for people living without it. “If you know that a particular vitamin is necessary for someone’s nutritional health, then you make sure they get that vitamin,” McGlone said. “I say the same thing about C-tactile afferents. It’s like a vitamin that maintains their mental health.” Maybe one day there will be “an emotional IcyHot,” Schaffler said, to give people the same emotional boost as a hug from a loved one.

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