Zapping specific neurons helps people walk again after spinal injury

ByCarissa Wong

Nine people with different degrees of lower bodyparalysisgained the ability to walk after receiving prolonged electrical stimulation to the injured area of their spine. This led to researchers identifying neurons that may help to improve walking ability post-paralysis.

脊髓的电刺激通常用于缓解疼痛in people with spinal cord injuries. In the latest discovery, electrical stimulation also accelerated walking recovery among people with spinal cord injuries who had enough functioning neurons in the affected area.

“我们模仿脊髓通常在您行走时通过来自大脑的电信号激活的方式，在正确的时间电气刺激脊髓的正确位置以移动腿部肌肉。”Jocelyne Blochat the University of Lausanne, Switzerland.

该团队将电气设备植入了九个在脊髓类似区域受伤的人的脊髓中。六名参与者的腿有一些感觉，但几乎没有能力移动它们，而剩下的三个也无法感觉到或根本无法移动他们的腿。

Electrical stimulation was applied to the participants’ spinal cords, with the pattern and location of these pulses being personalised via anartificial intelligence. The participants were then asked to walk as far as possible in 6 minutes.

With the support of a frame, the electrical stimulation enabled them to walk up to 25 metres.

Over the next five months, they continued to receive this electrical stimulation, alongside guided physiotherapy sessions, up to five times a week. At the end of the study period, they could walk 50 metres in 6 minutes, on average.

四个参与者甚至可能走不了路ny electrical stimulation, suggesting that the therapy induced sustained rewiring of spinal cord neurons.

To better understand how this occurred, the researchers induced spinal cord injuries in mice, paralysing their hind legs. They then implanted a device that delivered electrical pulses to the animals’ spines. Their walking ability subsequently improved.

Next, the researchers mapped the gene activity of the neurons at the mice’s spinal injury site, which revealed that a certain type of neuron became more active after electrical stimulation.

然后，他们使用了可以通过光控制的遗传工具来沉默并重新激活与步行恢复相关的神经元。只有在神经元打开时，修复的老鼠才能行走。

“After spinal cord injury, you have a lot of chaotic activity where a lot of neurons are trying to function,” says Bloch. “The electrical rehabilitation organises the network of cells and you actually increase the activity of a specific type of cell, while all the other cells are not activated.”

The researchers also found that silencing these neurons in mice that hadn’t been paralysed had very little effect on their walking ability.

“These cells are important for recovery of walking in injured mice, but when we switch them off in healthy mice without injury, it hardly affected their ability to walk,” says Bloch.

“The identification of a recovery-organizing cell type is a big step forward in our understanding of the mechanisms that underlie [electrical stimulation] rehabilitation,” wrote基恩·黄和Eiman Azim, at the Salk Institute for Biological Studies in California, in an accompanying opinion article.

将来，对这些神经元的操纵可能会揭示出在瘫痪后提高步行能力的新方法，黄和阿齐姆写道。

Journal reference:Nature,DOI: doi.org/10.1038/s41586-022-05385-7

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