Many groundbreaking findings have been made by studying a specialized animal species - a so-called "champion species." For example, our basic understanding of how neurons in human brains send signals came from studies of the giant nerves of squid, whereas discovery of the molecule (the acetylcholine receptor) that allows communication between nerves and muscles in humans came from studies of the electric eel. Using a similar approach here the researchers will study star-nosed moles and their relatives to understand the sense of touch at both the molecular and brain organization levels. Star-nosed moles have a characteristic star-shaped set of tentacles at the end of their snout; food is sensed and located by touch of the tentacles. Star-nosed moles have the most developed sense of touch of any mammal species. Surprisingly, the molecules that generate touch signals in the skin of mammals (and humans) remain undiscovered. Preliminary investigations show that star-nosed moles have great numbers of these molecules in their star, which may allow for a breakthrough in understanding how touch signals are generated. In addition to this goal, the researchers will investigate how space in the brain is devoted to processing the most important inputs. This is important because skilled behaviors (such as playing a musical instrument or typing on a computer) require large brain territories. This is well understood at the higher brain levels (such as the cerebral neocortex) but little is known about how space in lower areas of the brain pathways (the brainstem and thalamus) is divided up for skilled behaviors. Understanding both the molecules of touch and the way touch is processed in brains is a basic goal that will inform researchers about both normal and abnormal conditions in mammals and humans generally. In addition, the unique animals serve as vehicles for teaching about biology and senses to both students and the public. These investigations will provided compelling vehicles for teaching and will provide trainees with broad exposure to behavioral neurobiology ranging from behavior, to anatomy, to single-cell recordings and molecular biology.
Studies of star-nosed moles will explore the organization and representation of the unique "tactile fovea" on the nose. This small area of the star, used for high acuity touch, is over-represented in the brain, providing an opportunity for better understanding brain mapping related to behaviorally important body parts. In addition, the receptor-dense skin is useful for identifying the molecules that mediate touch in sensory neurons using bioinformatics. Eastern moles, on the other hand, have exceptional olfactory abilities and related behaviors that will allow for better understanding of how animals localize odorants and follow scent trails. Because all mammals share basic features of brain organization and function, findings will help us to understand general principles of how nervous systems process sensory information. More specifically, the star-nosed mole has advantages for understanding brain mapping and the relationship between primary afferents and areas of the central nervous system that represent behaviorally important skin surfaces. This is fundamental to our understanding of normal and abnormal brain organization and development.
