Lausanne researchers have designed a new technique, which represents hundreds of nerve cells in three dimensions with 50 times better resolution.
Digital Holographic Microscopy (DHM), borrowed from materials science, has immense potential for testing out new drugs to fight neurodegenerative diseases such as Alzheimer's and Parkinson's.
"DHM is a fundamentally novel application for studying neurons with a slew of advantages over traditional microscopes," explains Pierre Magistretti of EPFL's Brain Mind Institute and a lead author of the paper.
"It is non-invasive, allowing for extended observation of neural processes without the need for electrodes or dyes that damage cells."
Normally applied to detect minute defects in materials, Magistretti, along with DHM pioneer and EPFL professor in the Advanced Photonics Laboratory, Christian Depeursinge, decided to use DHM for neurobiological applications. In the study, their group induced an electric charge in a culture of neurons using glutamate, the main neurotransmitter in the brain. This charge transfer carries water inside the neurons and changes their optical properties in a way that can be detected only by DHM.
Thus, the technique accurately visualizes the electrical activities of hundreds of neurons simultaneously, in real-time, without damaging them with electrodes, which can only record activity from a few neurons at a time.
"Due to the technique's precision, speed, and lack of invasiveness, it is possible to track minute changes in neuron properties in relation to an applied test drug and allow for a better understanding of what is happening, especially in predicting neuronal death," Magistretti said.
"What normally would take 12 hours in the lab can now be done in 15 to 30 minutes, greatly decreasing the time it takes for researchers to know if a drug is effective or not," he added.
The study has been published in The Journal of Neuroscience.