MIMAS: An open-source microlens-array miniature microscope for accessible large-field cortical imaging in freely behaving mice.

MIMAS achieves cellular-resolution cortical imaging over a 4 × 4.5 mm² field in freely moving mice with only 2.31 g weight, using a simple microlens array.

• Why it matters: Understanding large-scale cortical dynamics during natural behavior is limited by complex, bulky imaging systems that are difficult for many labs to build or operate.
• What they did: The team developed MIMAS, an open-source, head-mounted fluorescence microscope replacing traditional optics with a 4 × 5 microlens array, enabling modular, wide-field imaging with computational stitching.
• The result: MIMAS successfully captured neuronal and vascular activity across multiple cortical regions during free behavior, providing a lightweight, accessible tool that broadens opportunities for large-scale cortical studies.