Patterned line-illumination mesoscopy with a moving slit for enhancing background suppression in cortex-wide mouse brain imaging

Wide-field mesoscopy provides the capabilities of cortex-wide field of view (FOV), cellular resolution and high frame rate for neuronal imaging in the mouse brain. However, inherent background fluorescence degrades the image quality and hinders neuronal signal extraction. To address this problem, we first introduce a cortex-wide, high-resolution line-illumination mesoscope with a moving slit designed for in vivo mouse brain imaging. This system achieves a 6.6×6.6 mm FOV, microscale cellular resolution, a high frame rate of 10 Hz, as well as the background rejection ability. Furthermore, we integrated patterned illumination into the system to enhance the background suppression. Experimental results show that the proposed system successfully captures neurodynamics in the living mouse brain. Compared with conventional wide-field mesoscopes, the cortex-wide patterned line-illumination mesoscope (PLIM) achieves a threefold increase in the signal-to-background ratio (SBR). With patterned illumination integrated, the SBR enhancement further reaches four-and-a-half-fold.