More than a feeling: scalp EEG and eye correlates of conscious tactile perception

Understanding the neural basis of consciousness is a fundamental goal of neuroscience. Many of the studies tackling this question have focused on conscious perception, but these studies have been largely vision-centric, with very few involving tactile perception. Therefore, we developed a novel tactile threshold perception task, which we used in conjunction with high-density scalp electroencephalography and eye-metric recordings. Participants were delivered threshold-level vibrations to one of the four non-thumb fingers, and were asked to report their perception using a response box. With false discovery rate (FDR) mass univariate analysis procedures, we found significant event-related potentials (ERP) including bilateral N140 and P300 for perceived vibrations; significant bilateral P100 and P300 were found following vibrations that were not perceived. Significant differences between perceived and not perceived trials were found bilaterally in the N140 and P300. Additionally, we found that pupil diameter and blink rate increased and that microsaccade rate decreased following vibrations that were perceived relative to those that were not perceived. While many of the signals are consistent with similar ERP-findings across sensory modalities, our results indicating a significant P300 in not perceived trials raise more questions regarding P300s perceptual meaning. Additionally, our findings support the use of eye metrics as a measure of physiological arousal as pertains to conscious perception, and may represent a novel path toward the creation of tactile no-report tasks in the future. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=81 SRC="FIGDIR/small/466706v1_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@e4e7fforg.highwire.dtl.DTLVardef@3b3ed0org.highwire.dtl.DTLVardef@198d517org.highwire.dtl.DTLVardef@cddef3_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIA novel tactile perceptual threshold task yields robust behavioral results C_LIO_LIEvent-related potentials differ according to perception status C_LIO_LIP300 is observed in both perceived and not perceived trials C_LIO_LIBlink rate, pupil diameter, and microsaccades differ across trial conditions C_LI