TBI induces neurodegeneration in different areas of the rat brain. Fluoro Jade (FJ) staining was performed on cryosections from rat brains to identify the damaged neurons 24 hours or 48 hours after the induction of mild lateral fluid percussion impact (LFPI). A. Representative low magnification (40X) photomicrographs showing FJ-positive neurons indicating neurodegeneration in cortex (left column), hippocampus (middle column) and thalamus (right column) 24 hours or 48 hours after LFPI. No degenerating neurons were observed in the corresponding brain regions in the sham animals. Scale bar = 500 μ. High magnification (400X) images from selected areas of respective sections are shown in the inset. Scale bar = 50 μ. B. The FJ-positive neurons were quantitated using the Image J program. The histograms show the estimation of FJ-positive neurons in cortex, hippocampus and thalamus. Cortex showed the highest number of injured neurons compared to other regions. Most FJ-positive neurons were observed after 24 hours of injury in all three regions. The numbers of degenerating neurons went down 48 hours after TBI but were significantly higher compared to sham animals. *** p < 0.001 compared to sham animals.