A hand on the shoulder can calm a crying child. The same pressure, applied harder or in the wrong place, produces a wince. Neuroscientist Ishmail Abdus-Saboor studies how the skin decides which of those outcomes it will deliver, and his work is exposing a sensory system far richer than the simple wiring diagrams of textbooks.
The skin is packed with specialised neurons tuned to different kinds of mechanical input: gentle stroking, sustained pressure, vibration, sharp pricks. Which cells fire, and in what combination, appears to determine whether a signal reaches the brain as pleasant or painful. Some of the same neurons can shift their allegiance depending on inflammation or injury, which helps explain why a light touch can hurt when you have sunburn.
Abdus-Saboor has turned to naked mole rats for clues. The animals live in crowded underground colonies where constant contact is unavoidable, and their skin seems unusually tolerant of it. Understanding how they manage that could inform better treatments for chronic pain and for conditions in which touch becomes unbearable.
