The three dimensional structure of the islands of Calleja: a single heterogenous cell complex.

The islands of Calleja in the rat brain stain brilliantly and stand out clearly using the NADPH-diaphorase histochemical staining. The 3-D structure of the Islands of Calleja was mapped in sagittal sections of young adult (3 months) and aged (28 months) animals. Contours were determined using a camera lucida method, and transferred to a computer equipped with an image analyzing system. Alignment of the sections using fixed anatomical anchers revealed that the islands of Calleja were one continuous structure at both ages studied. The structures varied between animals, and there was a pronounced left-right difference in the individual rats.