Tracing neuronal connections in postmortem human hippocampal complex with the carbocyanine dye DiI.
This report describes the ability of the carbocyanine dye DiI to trace hippocampal complex connections in a paraformaldehyde immersion-fixed human postmortem brain. Six months after the placement of DiI crystals into the hilus of the dentate gyrus, the CA1 hippocampal subfield and the lateral entorhinal cortex, 50-microns thick, vibratome cut sections were examined using an epifluorescence microscope with a rhodamine filter. In association with DiI-labeled granule, pyramidal and multipolar type neurons, we observed dendrites containing dendritic spines and axons. DiI-labeled fibers were observed coursing within classically described hippocampal pathways for at least 8 mm distal to the injection site. Photoconversion of diaminobenzidine (DAB)-treated DiI sections produced a stable record of labeled profiles. These findings indicate that DiI is a useful method for investigating intrinsic local circuit connections in normal aldehyde-fixed postmortem human brain and suggests that DiI could be a powerful tool to examine altered neural connectivity in humans with neurological disease.
Mufson
E J
EJ
Christopher Center for Parkinson's Research, Institute for Biogerontology Research, Sun City, AZ 85372.
Brady
D R
DR
Kordower
J H
JH
D000368:Aged; D000369:Aged, 80 and over; D002232:Carbocyanines; D004396:Coloring Agents; D006624:Hippocampus / Q000166:cytology*; D006801:Humans; D008297:Male; D008856:Microscopy, Fluorescence; D009434:Neural Pathways; D009474:Neurons / Q000502:physiology*; D013194:Staining and Labeling
D002232:Carbocyanines; D004396:Coloring Agents; C024286:3,3'-dioctadecylindocarbocyanine