Principles and applications of active tactile sensing strategies in the rat vibrissal system

The importance of active sensing to animals suggests that it may confer significant advantages to engineered sensing systems. The rat vibrissal (whisker) system is an important model for studying tactile active sensing. To date, however, the small size and fast speeds of the whiskers have precluded characterization of the rat's exploratory strategies. We have developed novel optical instrumentation that has allowed one of the first quantifications of tactile sampling during rat exploratory behavior. Results reveal characteristics of vibrissal active sensing that may find application in artificial tactile sensing systems; for example, the morphology of the whisker array allows rats to sample at multiple spatial scales within a single sampling cycle. Here, we describe the design and implementation of the novel optical system and how it is helping to uncover sampling strategies in this biological system.