Precision ventral extraction of implanted mouse brains: A protocol.

Neural implants are critical for modern mouse studies; however, permanent fixation of fibre optics or electrodes can render brain removal for histology particularly challenging. Frequent complaints include implant damage and tissue distortion. Here, we outline steps for transcardial perfusion and cranial isolation, then describe a precise dissection that facilitates brain extraction from the skull's ventral aspect. We further detail post-fixation and cryoprotection steps. Our approach is anchored in clear anatomical landmarks to ensure minimal tissue trauma, clean separation, and reproducibility. For complete details on the use and execution of this protocol, please refer to El-Fayomi et al.1.