title: All-optical histology using ultrashort laser pulses.
abstract: As a means to automate the three-dimensional histological analysis of brain tissue, we demonstrate the use of femtosecond laser pulses to iteratively cut and image fixed as well as fresh tissue. Cuts are accomplished with 1 to 10 microJ pulses to ablate tissue with micron precision. We show that the permeability, immunoreactivity, and optical clarity of the tissue is retained after pulsed laser cutting. Further, samples from transgenic mice that express fluorescent proteins retained their fluorescence to within microns of the cut surface. Imaging of exogenous or endogenous fluorescent labels down to 100 microm or more below the cut surface is accomplished with 0.1 to 1 nJ pulses and conventional two-photon laser scanning microscopy. In one example, labeled projection neurons within the full extent of a neocortical column were visualized with micron resolution. In a second example, the microvasculature within a block of neocortex was measured and reconstructed with micron resolution.
authors.affiliation: Department of Physics, University of California, San Diego, La Jolla, CA 92093, USA.
authors.forename: Philbert S
authors.initials: PS
authors.lastname: Tsai
authors.forename: Beth
authors.initials: B
authors.lastname: Friedman
authors.forename: Agustin I
authors.initials: AI
authors.lastname: Ifarraguerri
authors.forename: Beverly D
authors.initials: BD
authors.lastname: Thompson
authors.forename: Varda
authors.initials: V
authors.lastname: Lev-Ram
authors.forename: Chris B
authors.initials: CB
authors.lastname: Schaffer
authors.forename: Qing
authors.initials: Q
authors.lastname: Xiong
authors.forename: Roger Y
authors.initials: RY
authors.lastname: Tsien
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Squier
authors.forename: David
authors.initials: D
authors.lastname: Kleinfeld
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D016477:Artifacts; D005260:Female; D016591:Histocytological Preparation Techniques / Q000295:instrumentation / Q000379:methods*; D007150:Immunohistochemistry; D007834:Lasers; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D018613:Microscopy, Confocal / Q000295:instrumentation / Q000379:methods*; D019579:Neocortex / Q000378:metabolism / Q000648:ultrastructure; D009474:Neurons / Q000378:metabolism / Q000648:ultrastructure; D051381:Rats