Star-nosed Mole - Snout Comparison To Visual Organ

Snout Comparison To Visual Organ

Vanderbilt University neuroscientist Kenneth Catania, who has studied star-nosed moles for 20 years, recently turned his research to the study of star-moles as a route to understanding general principles about how human brains process and represent sensory information. He called star-moles "a gold mine for discoveries about brains and behavior in general—and an unending source of surprises".

Comparing the moles snout to vision, his research showed that whenever the mole touched potential food it made a sudden movement to position the smallest rays, the twin rays number 11, over the object for repeated rapid touches. He reports: "The similarities with vision were striking. The star movements resembled saccadic eye movements—quick movements of the eyes from one focus point to another—in their speed and time-course. The two 11th rays are over-represented in primary somatosensory cortex relative to their size, just as the small visual fovea in primates—a small region in the center of the eye that yields the sharpest vision—is over-represented in primary visual cortex." He notes that some bats also have an auditory fovea for processing important echolocation frequencies, suggesting that "evolution has repeatedly come to the same solution for constructing a high-acuity sensory system: subdivide the sensory surface into a large, lower-resolution periphery for scanning a wide range of stimuli, and a small, high-resolution area that can be focused on objects of importance".