Fig. 5.

Results of anatomical injection of BDA, an anterograde tracer, into the IPS. (A) View of the BDA injection site at the fundus of the IPS. (Inset) BDA staining on Nissl section, shown superimposed on a myelin-stained background. (B) Magnified view of the fundus depicting fluorescently immunolabeled BDA superimposed on a myelin-stained background. The dotted rectangle highlights a group of labeled fibers projecting from the fundus to deep white matter, crossing the superficial white matter. (C) Magnified view of the area within the dotted rectangle in B. The white dashed line indicates the WGB. (D) BDA-labeled white matter fibers from IPS fundus injection, magnified from the Inset in A. A group of labeled fibers (red arrowheads) projects radially through the superficial white matter into the deep white matter (dotted black rectangle). Sparse fibers oriented parallel (blue arrowheads) and perpendicular (black arrowheads) to the penetrating fiber group are visible also.