Brain responses to tactile stimuli: Re-examination in the light of electroencephalography and bispectral index system

Objective: The aim of this study was to investigate the brain responses to non-painful tactile stimuli in different sleep stages and in different region of the brain using the classical scoring methods as well as the BİS. Methods: Sleep data of 21 subjects were used in the study. Simultaneous electroencephalography and Bispektral Index system were used to record brain responses to non-painful tactile stimuli. Classical scoring system and BIS system were used to determinate the sleep stages. Brain responses to non-painful tactile stimuli were examined. Results: P50, N100, P200, N300, P450, N550, P900, and N_late components were detected against non-painful tactile stimuli. Using the BIS, the sleep process could be examined in more sub-periods than the classical stages. A high correlation was found between classical sleep stages and BIS in all measurement regions. Conclusion: This is the first study to show that sensory processing continues during sleep. This is the first study to evaluate brain responses to non-painful tactile stimuli during sleep by using BIS and EEG. In sleep, brain responses to the stimulus were found to be compatible with each other during classical sleep and BIS periods.