The gradual subjective consciousness fluctuation in implicit sequence learning and its relevant brain activity.

Existing studies have investigated gradual subjective consciousnesses, guess, intuition, fluency, rule, and memory, and their fluctuation behavioral characteristics in implicit learning, but they did not investigate or elucidate the underlying brain mechanisms. Therefore, the current study asked participants to report subjective consciousnesses in each trial of inclusion and exclusion tasks after implicit sequence learning and used the eyes-closed and eyes-opened resting-states' fMRI to examine the relevant brain areas of the five gradual subjective consciousnesses and their fluctuation. The results showed that: (1) There were many relevant resting-state brain areas of the five gradual subjective consciousnesses to reveal their brain mechanisms. In the eyes-closed and eyes-opened resting states, as the participants' consciousness level was gradually increasing from guess to intuition, to fluency, to rule, and to memory, the positively-relevant brain areas correspondingly changed from somatic motor to a mixture of somatic motor, consciousness, emotion feeling, and implicit learning; and then to a mixture of visual, somatic motor, and consciousness; and then to a mixture of visual, somatic motor, and consciousness; and then to a mixture of visual, somatic motor, and consciousness. The negatively-relevant brain areas correspondingly changed from a mixture of visual, consciousness, somatic sensory, and implicit learning to a mixture of visual, somatic motor, somatic sensory, and other consciousness; and then to memory; and then to a mixture of other somatic motors; and then to a mixture of other consciousness and other somatic motors. However, in the amplitude of low frequency fluctuations (ALFFs)-difference, the relative directions of the guess and intuition were almost opposite to those in the eyes-closed and eyes-opened resting states. But the relative directions of the fluency, rule, and memory were consistent with those in the eyes-closed and eyes-opened resting states. (2) There were significant gradual subjective consciousness fluctuations, including the gradual subjective consciousness fluctuation-all M and SD. There were many relevant resting-state brain areas of gradual subjective consciousness fluctuations to reveal their brain mechanisms. The gradual subjective consciousness fluctuation M was positively related to Calcarine_R, Lingual_R, Lingual_R, Temporal_Pole_Mid_L, ParaHippocampal_L, Vermis_1_2, and Vermis_7; but was negatively related to Calcarine_R. The gradual subjective consciousness fluctuation-all SD was positively related to Parietal_Inf_L, Thalamus_L, Temporal_Mid_L, Vermis_9, Parietal_Inf_L, and Thalamus_L and Thalamus_R; but was negatively related to Rolandic_Oper_R, Rolandic_Oper_R, Insula_L, Insula_R, Cingulum_Post_L, and Temporal_Mid_L. The detailed function of the relevant brain areas of consciousness fluctuations needs further investigation. (3) ALFFs in eyes-closed and eyes-opened resting states and their ALFFs-difference could differently predict the five gradual subjective consciousnesses and their fluctuations, indicating that using the two resting states was necessary, and the ALFFs-difference was a new quantitative sensitivity index of the gradual subjective consciousnesses and their fluctuations.