Blast-induced disruption of the piriform cortex, insular cortex, and secondary somatosensory cortex. Shown are diascopic bright/dark field images (A), H&E-stained (B) and collagen IV-immunostained (C) sections from a 3×-chronic exposure animal that was sacrificed 8.5 months post-blast. A tear (black arrow in panel A) can be seen that begins at the surface of the secondary somatosensory cortex and extends through insular cortex resulting in misalignment of the insular cortical layers. H&E staining (B) of the lesion at the cortical surface shows that layer I (arrow) of the secondary somatosensory cortex has been embedded into layers II and III. In a collagen IV-immunostained section (C) adjacent to that shown in panel B an artery (black arrows) and two arterioles derived from it are visible. H&E staining (D-E) shows interruption of the piriform cortex (black arrows) by the insertion of tissue that appears to have originated in the lateral olfactory tract/olfactory tubercle (white arrow) which is also visible in panel A (white arrow). Immunostaining with an antibody against CNPase (F) confirmed the myelinated nature of the repositioned tissue. Panel G shows the normal appearance of the piriform cortex in an H&E stained section from a control rat. Scale bars: 1 mm, A, D and G; 150 μm, B-C; 500 μm, E-F.