Related Experiment Video
Updated: Feb 10, 2026

Novel Passive Clearing Methods for the Rapid Production of Optical Transparency in Whole CNS Tissue
Published on: May 8, 2018
Novel Passive Clearing Methods for the Rapid Production of Optical Transparency in Whole CNS Tissue
Jiwon Woo1, Eunice Yoojin Lee2, Hyo-Suk Park3
1Department of Neurosurgery, Gangnam Severance Hospital, Yonsei University College of Medicine; Brain Korea 21 PLUS Project for Medical Science, Yonsei University; The Spine and Spinal Cord Institute, Biomedical Center, Gangnam Severance Hospital, Yonsei University College of Medicine.
Abstract:
Since the development of CLARITY, a bioelectrochemical clearing technique that allows for three-dimensional phenotype mapping within transparent tissues, a multitude of novel clearing methodologies including CUBIC (clear, unobstructed brain imaging cocktails and computational analysis), SWITCH (system-wide control of interaction time and kinetics of chemicals), MAP (magnified analysis of the proteome), and PACT (passive clarity technique), have been established to further expand the existing toolkit for the microscopic analysis of biological tissues. The present study aims to improve upon and optimize the original PACT procedure for an array of intact rodent tissues, including the whole central nervous system (CNS), kidneys, spleen, and whole mouse embryos. Termed psPACT (process-separate PACT) and mPACT (modified PACT), these novel techniques provide highly efficacious means of mapping cell circuitry and visualizing subcellular structures in intact normal and pathological tissues. In the following protocol, we provide a detailed, step-by-step outline on how to achieve maximal tissue clearance with minimal invasion of their structural integrity via psPACT and mPACT.
Related Concept Videos
Passive Filters
Low-Pass Filters
Low-pass filters are designed to transmit signals with frequencies lower than the cutoff frequency, ωc, and attenuate those above it. The cutoff...
Active versus Passive Immunity
Active Immunity
Active immunity refers to the resistance one develops...
CNS Depressants: Alcohol and Nicotine
CNS Depressants: Barbiturates and Benzodiazepines
CNS Stimulants: Psychedelic Agents
Passive Diffusion: Overview and Kinetics
When administered orally, drugs establish a substantial concentration gradient between the gastrointestinal (GI) lumen and the bloodstream, expediting...

