Encoding of Tactile Responses in the Periphery of the Somatosensory System

Biomimetics, or neuromimetics in particular, have held out the promise that by studying the nervous system we could discern optimal design strategies and parameters to develop better artificial devices. However, when studying natural systems it has proved difficult to abstract useful design strategies. One reason for this difficulty is the poor techniques for studying neural systems during natural behaviors. We developed a novel technique for studying cells in the trigeminal ganglion whose nerve terminals lie in the follicles surrounding the whiskers on the rats face and transduce tactile stimulation to electrical impulses for subsequent processing by the central nervous system. The goals of this work were to 1) determine if the passive response properties of these cells are used by the animal during natural exploration and 2) evaluate how these cells encode complex stimuli. We developed a novel method for chronically recording from these peripheral nerve cells and determined that 1) the passive response properties are used by these primary cells to encode sensory information during natural exploration and 2) while each cell has a narrow range of parameters that it responds to, the rat employs complex behavioral movements of the whiskers and head to optimize the probability of exciting these cells. As a population then, these cells convey complex features of their environment and the CNS uses precise spike timing to decode the information