Chronic stroke is often accompanied by tactile impairments that contribute to long-term disability in activities of daily living. While new rehabilitative interventions recently became available in the motor domain by using transcranial direct current stimulation (tDCS), there is no generally accepted treatment for tactile impairments after chronic stroke. Previous studies in healthy volunteers demonstrated that tactile acuity and haptic skills can be improved by applying a passive learning protocol to the fingertip (peripheral high-frequency stimulation, pHFS). Based on these findings, the purpose of this protocol is to enhance the beneficial effect of pHFS on implicit tactile and haptic learning in chronic stroke patients by a combined application of pHFS with tDCS (pHFS+tDCS) applied to the somatosensory cortex of the affected hemisphere. This approach might identify novel strategies to enhance functional recovery after stroke and might provide deeper insight into mechanistic information on the neural substrates involved in these behavioral gains. Primary outcome measures will be performance in a tactile grating orientation discrimination task (GOT) and in a haptic object recognition task. In order to obtain descriptive preliminary information on the relation between sensory improvements and motor deficits in chronic stroke patients, secondary outcome measures will be fine motor tasks such as a tapping task and a pegboard test (PBT) that require manual dexterity, handeye coordination, steadiness, and perceptual motor skills. To identify the operating mechanisms underlying hypothesized performance improvements after pHFS+tDCS, we will use paired-pulse protocols to evaluate changes in cortical excitability as well as fMRI in a subset of patients to identify cortical map reorganization in primary (SI) and secondary (SII) somatosensory cortex as well as in primary motor cortex (MI). Healthy volunteers will be tested (a) since there are no data available on performance of the haptic task in healthy subjects, (b) to obtain descriptive information on the influence of our interventions on this task for hypothesis generation purposes in our future investigations, and (c) because sensorimotor performance in the non-paretic hand of stroke patients is often not normal and therefore a poor sole control for performance of the paretic hand. Studies in chronic stroke patients will help address the main experimental hypothesis.