Altered neuron-specific nuclear protein (NeuN) reactivity in permeabilized neurons. (A) Some Lucifer Yellow (LY)+ cells are NeuN+ (open arrows), while others have lost their NeuN signal (closed arrows). Other LY+ cells appear to have weakened NeuN reactivity (arrowheads). Representative image from caudate of 15 min (0d) repetitive injury. LY, green; NeuN, red. Scale bars = 50 μm. (B-D) Quantification of the percentage of permeabilized cells that were NeuN+ per hemisphere, ± standard error of the mean (SEM). There were no significant differences in LY+ NeuN loss between injury groups. Overall, only 42.46% of permeabilized cells were NeuN+ in the caudate, while 92.49% of substantia nigra (SN) and 64.48% of superior colliculus (SC) permeabilized cells were NeuN+. (E-G) Quantification of permeabilized cells with or without NeuN co-expression in context with the percentage of permeabilized cells per hemisphere, ± SEM. LY+/NeuN-, green; LY+/NeuN+, red. Both the caudate (p = 0.0379) and SC (p = 0.0202) displayed significant differences in the amount of LY+/NeuN- cells, but these differences were not significant in multiple comparison analyses. The substantia nigra pars reticulata (SNpr) displayed no significant differences in the number of LY+/NeuN- cells (p = 0.1762). Color image is available online.