Summary:

- Researchers have developed an ultra-thin optical fiber probe that can be used to study the brain's neural activity with minimal disturbance.
- The probe is only 50 micrometers in diameter, making it virtually invisible to the naked eye, and can be inserted into the brain to record electrical signals from individual neurons.
- This technology allows for long-term, high-resolution monitoring of brain activity, which could lead to new insights into brain function and the development of more effective treatments for neurological disorders.