Introduction -- Comparative Studies of Somatosensory Systems and Active Sensing -- The Whisker Thalamus -- Synaptic Microcircuits in the Barrel Cortex -- Imaging the Cortical Representation of Active Sensing in the Vibrissa System -- The Rodent Vibrissal System as a Model to Study Motor Cortex Function -- The Central Pattern Generator for Rhythmic Whisking -- Functional principles of Whisker-mediated Touch Perception -- Location Coding by the Whisking System -- The Robot Vibrissal System: Understanding Mammalian Sensorimotor Co-ordination through Biomimetrics -- Impact of Monoaminergic Neuromodulators on the Development of Sensorimotor Circuits.