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Rats actively explore their environment by rhythmically sweeping their whiskers.As a consequence, neuronal activity in somatosensory pathways is modulated by the frequency of whisker movement.The potential role of rhythmic neuronal activity for the integration and consolidation of sensory signals, however, remains unexplored.Here, we show that a brief period of rhythmic vibrissal stimulation in anesthetized rats resulted in a frequency-specific and long-lasting increase or decrease in the amplitude and slope of somatosensory-evoked potentials in the contralateral primary somatosensory (barrel) cortex.Local application of AP-5 revealed that this vibrissa-to-cortex long-term plasticity in adult rat in vivo is NMDA receptor-dependent and the long-lasting plasticity caused by rhythmic vibrissal stimulation is generated in barrel cortex.Our results also showed that the long-lasting enhancement of the vibrissa-to-cortex evoked response was side-but not barrel-specific.Rhythmic vibrissal stimulation at 100 Hz applied to the vibrissa for 1 s in infant-trimmed [postnatal day (P) 1-7] rats could not cause an obvious long-lasting increase in the amplitudes of vibrissa-to-cortex evoked responses, but in rats whose whiskers clipped daily to within 2-3 mm of the skin surface for 7 d during P 29-35, the long-lasting increase in the amplitudes of vibrissa-to-cortex evoked responses could still be induced by 100 Hz vibrissal stimulation.Overall, our results suggest that natural, rhythmic patterns of whisker activity modify the cerebral processing of sensory information, providing a possible mechanism underlying sensory perception.