Feasibility and resolution limits of opto-magnetic imaging of neural network activity in brain slices using color centers in diamond

Abstract

We suggest a novel approach for wide-field imaging of the neural network dynamics of brain slices that uses highly sensitivity magnetometry based on nitrogen-vacancy (NV) centers in diamond. In-vitro recordings in brain slices is a proven method for the characterization of electrical neural activity and has strongly contributed to our understanding of the mechanisms that govern neural information processing. However, this traditional approach only acquires signals from a few positions, which severely limits its ability to characterize the dynamics of the underlying neural networks. We suggest to extend its scope using NV magnetometry-based imaging of the neural magnetic fields across the slice. Employing comprehensive computational simulations and theoretical analyses, we determine the spatiotemporal characteristics of the neural fields and the required key performance parameters of an NV magnetometry-based imaging setup. We investigate how the technical parameters determine the achievable spatial resolution for an optimal 2D reconstruction of neural currents from the measured field distributions. Finally, we compare the imaging of neural slice activity with that of a single planar pyramidal cell. Our results suggest that imaging of slice activity will be possible with the upcoming generation of NV magnetic field sensors, while single-shot imaging of planar cell activity remains challenging.

Optimization of a Diamond Nitrogen Vacancy Centre Magnetometer for Sensing of Biological Signals

“…For widefield imaging, a goal is to image the field from biological signals (such as neuron action potentials) [20,21]. However, the pixel imaging sensitivity is on the order of 250 nT-2 µT/ √ Hz, as yet insufficient for imaging pT-level fields [22]. Biosensing imaging work has therefore focused on samples which have a strong magnetic field due to the presence of ferromagnetic material [23][24][25].…”

Optical Characterization of Nitrogen-Vacancy Centers Created by Proton Implantation in Diamond

“…In this work, we describe the preparation of approximately 20 µm thin layers of NV centers by proton beam irradiation of a commercially available type-Ib diamond. Such thin sensor layers are useful for two-dimensional magnetic field imaging applications [12][13][14].…”

Quantum Sensing in a Physiological‐Like Cell Niche Using Fluorescent Nanodiamonds Embedded in Electrospun Polymer Nanofibers

“…Moreover, NV based approaches overcome many of the drawbacks of existing methods such as the inherent invasiveness, low throughput and lack of spatial information associated with patch clamping as well as difficulties associated with fluorescence based sensors, namely the requirement for genetic manipulation, or observed cytotoxicity of many fluorescence based probes . To date, a number of studies have considered in detail the different experimental parameters necessary for maximizing measurement sensitivity in NV based sensing of neuronal action potentials . For example, a recent demonstration of optomagnetic detection of single axonal potentials employed a MW lock in detection method to manipulate the NV spin state, citing sensitivity at a distance of 10 µm from the sample and by integrating the signal over a relatively large surface area (≈8 mm 2 ) of 15 pT Hz −1/2 .…”