For over two decades, neuroscientists have been using in vivo microscopy to study the structure and function of neurons in the living brain. Most of this work has focused on the superficial cerebral cortex, whilst regions located deep in the brain have remained relatively impervious to non-invasive optical probing. Many of these regions are implicated in important neuronal processes such as gating of sensory and motor information, learning and memory, as well as neurological diseases such as Alzheimer’s, Huntington and Parkinson’s. An exciting new study by Vasquez-Lopez, S.A. et al., demonstrates the use of a novel microscopy method for minimally invasive in vivo imaging in deep brain regions using a tiny optical fibre the width of a human hair.
The study, published in the current issue of the journal "Light: Science & Applications", demonstrated how this novel imaging method can be used to acquire fully resolved images of subcellular neuronal structure with micrometre resolution and minimal probe footprint. The method makes use of holographic light control to acquire images without the need for bulky objectives which can cause considerable damage to the tissue overlying the structures of interest. The volume of tissue lesion was reduced by more than 100-fold, compared to other endoscopic methods, while preserving image quality. These results represent a major breakthrough in the compromise between high-resolution imaging and tissue damage, heralding new possibilities for deep-brain imaging in vivo. Future developments will now aim to achieve the scanning speeds necessary for dynamic imaging over wider areas, enabling neuronal population activity to be monitored and a critical step toward brain imaging in freely moving animals.