It is well known that both the movement of the hand itself and the mental representation of it lead to event-related desynchronization (ERD) of EEG recorded over the corresponding motor areas of the cerebral cortex. Similarly, in somatosensory cortical areas, ERD occurs upon tactile stimulation of the hand, but whether this effect is caused by mental representation of sensations from tactile stimulation remains poorly understood. In the present study, the effects on the EEG of imaginary vibrotactile sensations on the right hand were compared with the effects of real vibrotactile stimulation. Both actual vibrotactile stimulation and mental representation of it have been found to elicit contralateral ERD patterns, particularly prominent in the μ-band and most pronounced in the C3 region. The paper discusses tactile imagery as a part of the complex sensorimotor mental image and its prospects for using EEG patterns of imagery-induced tactile sensations as control signals in BCI circuits independently and when combined with ERD based on movement imagination to improve the efficiency of neurointerface technologies in rehabilitation medicine, in particular, to restore movements after a stroke and neurotrauma.

It is well-known that both hand movements and mental representations of movement lead to event-related desynchronization (ERD) of the electroencephalogram (EEG) recorded over the corresponding cortical motor areas. However, the relationship between ERD in somatosensory cortical areas and mental representations of tactile sensations is not well-understood. In this study, we employed EEG recordings in healthy humans to compare the effects of real and imagined vibrotactile stimulation of the right hand. Both real and imagined sensations produced contralateral ERD patterns, particularly in the μ-band and most significantly in the C3 region. Building on these results and the previous literature, we discuss the role of tactile imagery as part of the complex body image and the potential for using EEG patterns induced by tactile imagery as control signals in brain-computer interfaces (BCIs). Combining this approach with motor imagery could improve the performance of BCIs intended for rehabilitation of sensorimotor function after stroke and neural trauma.Significance StatementIn this study, we address the issue of mental representations in the somatosensory domain. By assessing the dynamics of sensorimotor EEG rhythms and the distribution of topographical EEG patterns, we demonstrate that tactile imagery produces event-related desynchronization in the contralateral EEG, even in the absence of physical stimulation. Our results clarify the neurophysiological mechanisms underlying the occurrence of ERD in the mu rhythm and its relationship to somatosensory cortical processing.

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