Cortical Alpha Oscillation During 3 kHz Steady-State Sinusoidal Electric Current Stimulation

Abstract

Little is known about the changes in ongoing cortical rhythms due to application of the steady-state sinusoidal electrical stimuli of 3 kHz, although it has been shown to elicit tactile sensations. In addition, it is known that somatosensory stimulation attenuates ongoing alpha rhythm in centroparietal cortex. Thus, the present work aimed to evaluate alpha rhythm alterations in sensorimotor area and sensations perceived with application of 3 kHz sinusoidal stimulus. Sensory perception threshold (ST) was measured in ten healthy volunteers for posterior stimulation in three distinct stimulus intensities (1.1xST, 2xST and 3xST). Cognitive evaluation of perceived sensations was obtained through questionnaires and cortical alpha rhythm blockade profile was evaluated through the classical event-related synchronization/ desynchronization method. Results showed alpha attenuation in the central cortex bilaterally, in the ipsilateral pre-frontal cortex and contralateral parietal cortex during stimulation. Moreover, there was a tendency of bilateral centroparietal alpha rhythm desynchronization increase with stimulus intensity. In conclusion, sinusoidal electrical stimulation may be useful for disease diagnostics and treatment as well as neurofeedback for brain-machine interface (BMI) applications. Patients may benefit from the novel objective method proposed for assessment of tactile perception, mainly, who might not have their cognition preserved (e.g., stroke).