Testing the Process Dissociation Procedure by Behavioral and Neuroimaging Data: The Establishment of the Mutually Exclusive Theory and the Improved PDP

Abstract

The process dissociation procedure (PDP) of implicit sequence learning states that the correct inclusion-task response contains the incorrect exclusion-task response. However, there has been no research to test the hypothesis. The current study used a single variable (Stimulus Onset Asynchrony SOA: 850 ms vs. 1350 ms) between-subjects design, with pre-task resting-state fMRI, to test and improve the classical PDP to the mutually exclusive theory (MET). (1) Behavioral data and neuroimaging data demonstrated that the classical PDP has not been validated. In the SOA = 850 ms group, the correct inclusion-task response was at chance, but the incorrect exclusion-task response occurred greater than chance. In the SOA = 850 ms group, the two responses were not correlated, but in the SOA = 1,350 ms group and putting the two groups together, the two responses were in contrast to each other. In each group, brain areas whose amplitude of low frequency fluctuations (ALFFs) in the resting-state related to the two responses were either completely different or opposite to one another. However, the results were perfectly consistent with the MET proposed by the present study which suggests that the correct inclusion-task response is equal to the correct exclusion-task response is equal to C + A1, and the incorrect exclusion-task response is equal to A2. C denotes the controlled response and A1 and A2 denote two different automatic responses. (2) The improved PDP was proposed to categorize the 12 kinds of triplets as delineating four knowledge types, namely non-acquisition of knowledge, uncontrollable knowledge, half-controllable knowledge, and controllable knowledge with the MET. ALFFs in the resting-state could predict the four knowledge types of the improved PDP among two groups. The participants’ control of the four knowledge types (degree of consciousness) gradually improved. Correspondingly, the brain areas in the resting-state positively related to the four knowledge types, gradually changed from the sensory and motor network to the somatic sensorimotor network, and then to the implicit learning network, and then to the consciousness network. The brain areas in the resting-state negatively related to the four knowledge types gradually changed from the consciousness network to the sensory and motor network. As SOA increased, the brain areas associated with almost all the four knowledge types changed. (3) The inhomogeneous hypothesis of the MET is best suited to interpret behavioral and neuroimaging data; it states that the same components among the four knowledge types are not homogeneous, and the same knowledge types are not homogeneous between the two SOA groups.

The ecological validity of MET was favourable in sitting implicit sequence learning consciousness by eyes closed and eyes open resting states fMRI

“…If the relevant resting-state brain areas of two cognitive tasks differ, the brain mechanisms of these cognitive tasks are different. The relevant resting-state brain areas of a cognitive task are usually proved to be activated by task-state fMRI when the cognitive task is carried out 21 – 23 , 27 , 32 – 33 , which is also holds true for the current study, see results and discussion for details. Therefore brain spontaneous activity in resting-state is a stable indicator of individual cognitive characteristics 38 .…”

“…Zhang et al 33 for the first time tested the PDP improved by Fu et al (2010, 2013) by both behavior and neuroimaging with eyes-closed resting-state fMRI (Zhang et al were also the authors of the current study). They pointed out that the PDP was not established.…”

“…Only the target circle was filled in blue; the other circles were outlined in blue, with unfilled centers. The target-circle location order followed the SOC sequence rule: 3-4-2-3-1-2-1-4-3-2-4-1 5 , 8 , 26 , 33 , in which each target location was determined by two prior target locations, and three target locations formed a smallest-rules unit, namely a triplet.…”

“…Because the study used the dichotomy, it did not assess consciousness in implicit sequence learning and could not separate implicit sequence learning from consciousness (Please see “ The implicit-sequence-learning consciousness and its brain mechanism using the dichotomy ” for details). Zhang et al 33 tested the PDP and explored relevant resting-state brain areas of the MET knowledge with eyes-closed resting-state fMRI (Please see “ The MET and its brain mechanism ” for details), but they did not consider the resting-state types and the ecological validity of the MET.…”

“…Although Zhang et al 33 successfully tested the PDP and presented a more logical and data-friendly MET theory to quantify the MET knowledge in implicit sequence learning by both behavior and neuroimaging with eyes-closed resting-state fMRI, there were problems with the ecological validity of the MET. (1) Participants completed implicit sequence learning while lying down and receiving task-state scanning.…”