Concurrent ultra-high field fMRI and optical imaging of hemodynamic parameters and intracellular calcium

Motivation: BOLD fMRI is widely used as an indirect measure of neuronal activity. However, the spatial and temporal specificity of the BOLD signal is still under debate. Goal(s): Being able to measure both hemodynamics and neuronal activity simultaneously with fMRI can help to improve interpretation of the BOLD signal. Approach: A combined in-bore setup for concurrent intrinsic optical imaging, calcium imaging and ultra-high field fMRI in rats was designed. Results: Measurements of BOLD, intrinsic hemodynamic and calcium signals with high temporal and spatial resolution reveal high correlation between these signals with specific characteristics regarding localization, vascularization and fMRI sequence. Impact: A combined in-bore setup for concurrently recording calcium, intrinsic optical signals and fMRI was developed, which can be used to investigate spatial and temporal characteristics and correlations between brain activation, hemodynamic changes and BOLD signals.