Differential priming effects of color-opponent subliminal stimulation on visual magnetic responses

We investigated the effects of subliminal stimulation on visible stimulation to demonstrate the priority of facial discrimination processing, using a unique, indiscernible, color-opponent subliminal (COS) stimulation. We recorded event-related magnetic cortical fields (ERF) by magnetoencephalography (MEG) after the presentation of a face or flower stimulus with COS conditioning using a face, flower, random pattern, and blank. The COS stimulation enhanced the response to visible stimulation when the figure in the COS stimulation was identical to the target visible stimulus, but more so for the face than for the flower stimulus. The ERF component modulated by the COS stimulation was estimated to be located in the ventral temporal cortex. We speculated that the enhancement was caused by an interaction of the responses after subthreshold stimulation by the COS stimulation and the suprathreshold stimulation after target stimulation, such as in the processing for categorization or discrimination. We also speculated that the face was processed with priority at the level of the ventral temporal cortex during visual processing outside of consciousness.