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Yu J, Gutnisky DA, Hires SA, Svoboda K (2016) Layer 4 fast-spiking interneurons filter thalamocortical signals during active somatosensation. Nature Neuroscience, 19(12):1647-1657    
During tactile exploration, neural activity related to movement of digits or whiskers is suppressed to facilitate high signal-to-noise ratio encoding of touch. The authors show that in mouse this computation occurs in layer 4 of the barrel cortex and is mediated by fast-spiking interneurons
We rely on movement to explore the environment, for example, by palpating an object. In somatosensory cortex, activity related to movement of digits or whiskers is suppressed, which could facilitate detection of touch. Movement-related suppression is generally assumed to involve corollary discharges. Here we uncovered a thalamocortical mechanism in which cortical fast-spiking interneurons, driven by sensory input, suppress movement-related activity in layer 4 (L4) excitatory neurons. In mice locating objects with their whiskers, neurons in the ventral posteromedial nucleus (VPM) fired in response to touch and whisker movement. Cortical L4 fast-spiking interneurons inherited these responses from VPM. In contrast, L4 excitatory neurons responded mainly to touch. Optogenetic experiments revealed that fast-spiking interneurons reduced movement-related spiking in excitatory neurons, enhancing selectivity for touch-related information during active tactile sensation. These observations suggest a fundamental computation performed by the thalamocortical circuit to accentuate salient tactile information