Brain imaging for neural tissue health assessment

Optical neuroimaging technologies aim to observe neural tissue structure and function by detecting changes in optical signals (scatter, absorption, etc..) that accompany a range of anatomical and functional properties of brain tissue. At present, there is a tradeoff between spatial and temporal resolution that is not currently optimized in a single imaging modality. This work focuses on filling the gap between the spatio-Temporal resolutions of existing neuroimaging technologies by developing a coherent optics-based imaging system capable of extracting anatomical and functional information across a measurement volume by leveraging a coherent optics-based approach that provides both magnitude and phase information of the sample. We developed a digital holographic imaging (DHI) system capable of detecting these optical signals with a spatial resolution of better than 50 μm over a twenty-five mm² field of view at sampling rates of 300 Hz and higher. The DHI system operates in the near-infrared (NIR) at 1064 nm, facilitating increased light penetration depths while minimizing contributions from overt changes in oxy-and deoxy-hemoglobin concentration present at shorter NIR wavelengths. This label-free imaging method detects intrinsic signals driven by tissue motion, allowing for innately spatio-Temporally registered extraction of anatomical and functional signals in vivo. In this work, we present in vivo results from rat whisker barrel cortex demonstrating signals reflecting anatomical structure and tissue dynamics.