Research suggests there could be a simple, safe, and economical way to relieve pain: green light. And a new animal study reveals the biological basis of how it might work.
Scientists have been exploring the pain-relieving effects of green light for at least half a decade, uncovering an occasional clue on exactly how it happens. This new mouse study, led by neuroscientist Yu-Long Tang of Fudan University in Shanghai, further specifically reveals the eye cells and brain pathways that support the pain relief sometimes felt after exposure to low-intensity green light. It was discovered that cones and rods (视锥细胞和视杆细胞) —the eye cells that sense light—contributed to the pain-relieving effects of green light in healthy mice and mice with diseases.
As scientists often do, the researchers inactivated certain cells to see what effect that had on the animals’ sense of pain. When they inactivated the rods in some mice, those animals showed only partial relief with green light, while mice without cones showed no signs of pain relief at all when bathed in green light.
“We found that cones are essential for green light analgesia (痛觉缺失), while rods play a secondary role,” explained Tang and his colleagues in their published paper. From there, they followed the path taken by electrical signals from the eye through the brain.
Bathed in green light, the cones and rods stimulated a group of brain cells, which has previously been linked to the analgesic effects of bright light in general. In this part of the brain, these neurons (神经元) express something involved in pain signaling. These cells then relay the message to another part of the brain that deals with pain, effectively turning down the sensation of severe pain.
Pain relief in animals is a far cry from humans, but this study succeeds in locating pain circuits in the brain that respond to visual inputs and expands our understanding of a safe, easy way to possibly relieve them.
【小题1】What can we learn about the new study from paragraph 2?| A．It’s the first of its kind. |
| B．It’s performed on different animals. |
| C．It’s cooperation between universities. |
| D．It’s more precise than previous studies. |
| A．By analyzing data. | B．By making surveys. |
| C．By classifying cases. | D．By doing experiments. |
| A．The effect of green light. | B．The importance of neurons. |
| C．The biological basis of the finding. | D．The operating principle of brain cells. |
| A．Approving. | B．Doubtful. |
| C．Dismissive. | D．Unclear. |
