Photoacoustic and fluorescence hybrid microscope for cortex-wide imaging of neurovascular dynamics with subcellular resolution.

Simultaneously monitoring cortex-wide microvascular dynamics, blood oxygenation metabolism, and neuronal activities with high spatiotemporal resolution is essential for understanding neurovascular coupling (NVC). However, it remains a challenge for existing neuroimaging tools. Here, we report a linear transducer array-based hybrid microscope (LiTA-HM) that integrates photoacoustic microscopy and confocal fluorescence microscopy to achieve simultaneous neurovascular imaging with a field of view (FOV) of 6 millimeters by 5 millimeters, a spatial resolution of ~6 micrometers, and a temporal resolution of 0.8 seconds. We design an array of eight miniature transducers to enlarge FOV and optimize a polygon mirror-based ultrafast scanner to achieve real-time imaging. Proof-of-concept imaging experiments were conducted on awake mice. Different couplings between thousands of neuron somas and vessel branches down to capillaries were observed in hypoxia and anesthesia experiments. Spatiotemporal correlations and functional connectivity in NVC were uncovered for spreading depolarization waves occurred in a drug-induced epilepsy experiment. We expect that LiTA-HM will enable broad applications of neuroimaging.