A Star in the Brainstem Reveals the First Step of Cortical Magnification
Figure 1
Comparison of the facial anatomy and trigeminal sensory complex of a hairy-tailed mole (Parascalops breweri) and star-nosed mole (Condylura cristata).
A. A hairy-tailed mole has the typical body plan for a mole, with large forelimbs, small eyes, and a prominent but unspecialized nose. B. A horizontal section through the brainstem of a hairy tailed mole showing the trigeminal nerve (V), principal trigeminal sensory nucleus (PrV), and the spinal trigeminal nuclei (Sp50 – oral subnucleus, Sp5I - interpolar subnucleus, Sp5C - caudal subnucleus). The brainstem trigeminal nuclei of the hairy-tailed mole are similar to those of laboratory mice and rats. C. The star-nosed mole with an elaborate, mechanosensory nose. D. A horizontal section through the brainstem of a star-nosed mole. In star-nosed moles, PrV is greatly expanded in both rostral and medial-lateral directions. Note that the sections in B and D were cut horizontally relative to the separated brainstem, such that the ventral surface defined the horizontal plane.