Imaging the brain across scales using light, magnetic fields, and models*

Functional Magnetic Resonance Imaging (fMRI) is a powerful tool to map brain activity non-invasively and is the foundation of tens of thousands of published neuroscience studies. However, fMRI does not measure neurons directly. Instead, in the most common form of fMRI called Blood Oxygen Level Dependent (BOLD), changes in the concentration of paramagnetic deoxyhemoglobin in the blood are detected. Although BOLD is correlated with neural activity, its interpretation in healthy and diseased brain remains limited.
Animal models provide invaluable insight for studying the cellular origin of fMRI. In mice, state-of-the-art optical technologies have been developed to probe neuronal activity, blood flow and oxygenation while manipulating cell-type-specific neuronal activity.
A framework for imaging the brain of awake behaving mice across scales, from two-photon microscopy at the micrometer scale to macroscopic fMRI, will be demonstrated. High-resolution 3D images of cerebral vasculature measured in mice can be graphed into a connected network to model blood circulation and oxygen diffusion. In this model, the physics of magnetic resonance are leveraged to predict human brain imaging signals. Applications in neuroscience and fundamental cancer research will be discussed.