Simultaneous high-resolution imaging of individual neurons within a population using fluorescence of nitrogen-vacancy centers in nanodiamonds

• Applicant: Dr. Dominika Lyzwa
• Subject Area: Cognitive, Systems and Behavioural Neurobiology ; Experimental Condensed Matter Physics ; Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas ; Statistical Physics, Nonlinear Dynamics, Complex Systems, Soft and Fluid Matter, Biological Physics
• Term: from 2016 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 327306593

How the human brain works is one of the biggest questions of the21st century and huge investments have been made with a view toadvancing our understanding of this highly complex system. Exploringhow information is represented at the level of a population ofconnected neurons is an essential step towards answering thisquestion. In particular, how neurons within a network interact toprocess information and which role the correlations of their activityplay for the encoding of sensory information is not well understood. Inorder to investigate the representation and propagation of informationthrough the network, it is necessary to measure the voltageresponses, the spiking activity, of these neurons. Techniques toopticallly measure spiking activity for several single neuronssimultaneously with sufficiently high temporal and spatial resolution inreal-time have not yet been developed. Such high-resolution sensingand imaging techniques are also interesting for cell biology,biomedical applications and cancer research. In this project at theMassachusetts Institute of Technology, in an interdisciplinaryapproach, techniques for high-resolution optical sensing and imagingof cellular activity are developed. Methods are developed to opticallymeasure cellular activity using relaxation times of nitrogen-vacancycenters in nanodiamonds. The electron spin of the defect centers isaddressed experimentally with laser light and read out. The Nitrogen-Vacancy (NV) color centers are crystallographic defects in thediamond lattice. They have been shown to change fluorescence whenan external magnetic field changes. This property along with the nontoxicityof the nanodiamonds as well as the long coherence times ofthe NV spin triplet electronic state, which increases probing sensitivity,high photostability and brightness, make them exceptional nanoprobes in living organisms. Additionally, phase microscopy is used tooptically measure action potentials of cultured neurons with highresolution, non-invasively. Here, it is employed that an ongoing actionpotential, a rapid change of the membrane potential, leads tomeasurable fluctuations of the cell membrane and change in therefractive index of the cell. Given my background in experimentalphysics and computational neuroscience I believe that I am in an optimal position to perform this interdisciplinary research.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professor Peter So, Ph.D.