Figure 8

Ectopic neurons in neocortical layer I of blast-exposed animals. Shown are H&E (B and C) or NeuN (D and H, green) staining of the primary visual cortex from a 3×-chronic exposure animal analyzed 10 months after the blast exposure. H&E staining from the corresponding area in a control rat is shown in panel A. Panel B shows two areas (arrows) where the cortical layers have been disrupted. In the region indicated by the right arrow, ectopic cells are visible in layer I. This region is shown at higher magnification in panel C. The phenotype of the ectopic cells was determined to be neuronal by NeuN immunostaining (D and H, green), combined with DAPI staining (D and I, blue). The cortical layers around the left arrows (B) are also misaligned. The ectopic neurons were repositioned from cortical layers II and III. Note the presence of spindle-shaped cells (black arrows in C) and their NeuN staining shown in D (white arrows). Panels F and G show H&E staining of primary somatosensory cortex from another 3 ×-chronic exposure animal also analyzed at 10 months post blast. Panel G shows the same region at a higher magnification. The blast produced a tear that disrupted layers I to III with the result that a portion of layers II and III (arrow in both panels F and G) was avulsed and repositioned. NeuN (J) and DAPI (K) staining of the region demonstrated the neuronal character of the ectopic cells. The corresponding area from a control rat is shown in panel E. Scale bars: 200 μm, A, B, E and F; 50 μm, C and G; 10 μm, D; 100 μm, H, I, J and K.