Steven Hsiao: In Memoriam

Steven Hsiao Hopkins neuroscientist Steven Hsiao, one of the world’s leading experts on the neural basis of touch, passed away on June 16, 2014 at the age of 59 from lung cancer. Steve, the heir of an eminent line of sensory neuroscientists that included Vernon B. Mouncastle and Kenneth O. Johnson, sought to understand the neural code: how do spatio-temporal patterns of activity along the neuraxis— from the nerve through several levels of processing in cortex—encode information about the environment? What language do neurons use to communicate with each other? In addressing questions of neural coding in the sense of touch, and following the example of his illustrious mentors, Steve fearlessly tackled the hard problems that face somatosensory research. For example, as there is no off-the-shelf tactile equivalent of visual monitors or audio speakers, Steve designed and constructed sophisticated pieces of experimental apparatus to probe the sense of touch. Steve also embraced and elaborated on the cutting edge of mathematical approaches to address neural coding. Steve believed that, to achieve a true understanding of neural coding, one had not only to develop a mechanistic understanding of how stimulus properties are encoded in the neuronal activity, but also to link these patterns of neuronal activity to perception. Steve’s study of roughness perception, which he carried out with Ken Johnson and other colleagues at Hopkins, provides a nice illustration of his multifaceted approach to sensory neuroscience. For a decade, Ken had been trying to understand how textured surfaces are represented in the responses of nerve fibers (Johnson and Lamb, 1981). When Steve joined Ken’s lab in the late eighties, he became involved in this project. The story goes that he was running his fingers across one of the textured ‘‘drums’’ that were used in the neurophysiological experiments. The drum was a cylinder on which dots had been embossed in different configurations. Steve noticed that, as the dots got further apart, the surface of the drum became rougher,