A paper was recently published by a group of LabCrono UFPR Brazil. The study features a novel tactile stimulation during sleep. It was shown that this technique did not impact on the offline gains in motor skill, but altered slow oscillations and spindle densities. Alterations in electrophysiology parameters didn’t translate into behavioral changes.
Paper available at: http://www.sciencedirect.com/science/article/pii/S0031938416302931