Scientists have observed the neuronal structures inside deep brain areas of living mice at high resolution using a multimode optical fiber as thin as a human hair. They created a probe that can capture 7-kilopixel images with micron-level spatial resolution at imaging speeds of 3.5 frames per second. The probe may offer a sufficient spatial and temporal resolution for fluorescent imaging of subcellular structures in living tissues.
The researchers used the probe to image brain cells and neuronal processes in living mice’s visual cortex and hippocampus. They achieved spatial resolution close to one micron while causing minimal damage to the tissue surrounding the fiber penetration area. The probe’s rugged design allowed for continuous imaging for several hours.
Neuroscientists will be able to investigate the functions of neurons in deep structures of the brain of behaving animals using this minimally invasive approach. The new probe’s use could better understand the functions of deeply hidden brain compartments, such as memory formation, and related dysfunctions, such as Alzheimer’s disease.
The new probe may also pave the way for in vivo implementation of various modern microscopy techniques, such as multiphoton, superresolution, and light-sheet approaches. According to the researchers, future advancements will rely on developing new fiber types directly optimized for holographic endoscopy. The research team plans to expand on its findings by investigating advanced microscopy techniques using single fiber endoscopes.