Sensory information processing in the dorsal column nuclei by neuronal oscillators.

The dorsal column nuclei, a first relay station of the somatosensory system, express coherent oscillatory activity in the 4-22 Hz frequency range at single unit, multiunit and local field potential levels. This activity appears spontaneously (33% of the cases) or, more commonly (83%), during natural sensory stimulation of the receptive field. Such oscillations are not imposed upon the dorsal column nuclei by incoming sensory afferents nor cortico-nuclear projections, which indicates that they are generated within the dorsal column nuclei. We concluded that dorsal column nuclei transform a non-rhythmic input from the periphery to a populational oscillatory output to the somatosensory thalamus during sensory stimulation.