Functional Near-infrared Spectroscopy Based Neurofeedback Improves Conflict Adaptation

In the face of complex and changeable environment,people need to adjust their behaviors timely according to the changes of environment,and researchers study how individuals make flexible adjustment by studying the conflict adaptation effect.Conflict adaptation effect refers to the fact that when individuals perform congruency task(such as Stroop task,etc.),the conflict they experienced in the previous trial will make them better solve conflicts in the current trial.Conflict adaptation has attracted much attention because it reflects the ability of individuals to make flexible adjustments in complex environment.However,few studies have reported on whether conflict adaptation can be improved through known training intervention methods,which may be because conflict adaptation is a complex cognitive function involving completely different cognitive processes,making it difficult to improve through traditional methods(such as cognitive training).In recent years,neuroimaging-based neurofeedback has gradually become a popular training method due to its non-invasiveness,short periodicity and effectiveness.This study focused on whether the nirs-based neural feedback can effectively improve the individual ability to adapt to conflict,and magnetic resonance imaging technology was combined to explore the effect of neural feedback training on the brain activity in resting state.The purpose of study one was to investigate whether the nirs-based neural feedback training could improve individual conflict adaptation.Before and after the training,the traditional word color Stroop task was used to investigate the individual’s conflict adaptation,and the subjects were required to ignore the word meaning of the stimulus and respond to the word color.When selecting the target brain area,considering the lateralization in conflict adaptation,the experimental group included two different conditions: one group took the left dorsolateral prefrontal cortex(left DLPFC)as the target brain area,and the other group took the right dorsolateral prefrontal cortex(right DLPFC)as the target brain area.During the training,the subjects were required to adjust their brain activity according to the given strategies,but only the experimental group received the real feedback signal,and the feedback signal of the control group was derived from the brain signal of the experimental group.After eight times of training,the study found that the experimental group can stabilize the activation of the corresponding DLPFC,but only for left DLPFC targeted group who performed worse in the pretest significantly improved the conflict adaptation after the training.The result shows the neurofeedback training can improve the conflict adaptation,but only has a significant effect on poor individuals.Moreover,the experiment offered a causal evidence showing that the left DLPFC was indeed a core brain region in conflict adaptation.But for the role of right DLPFC,considering the Stroop task whose processing is lateralized,this study cannot conclude that the right DLPFC is not a core brain region in conflict adaptation.The study1 confirmed the effectiveness of nirs-based neurofeedback training on improving the conflict adaptation.Moreover,on one hand,we want to further answer the questions raised by study1,and to clarify the role right DLPFC in conflict adaptation.On the other hand,we want to explore the effects of neurofeedback training on brain activity through magnetic resonance imaging(fMRI).In order to avoid the influence of experimental paradigm on lateralization,the pre-and post-training task of study 2 was changed to Flanker task,and mri protocol was added to obtain the brain data of subjects in resting state.The training setup was the same as in experiment l.The experimental results showed that after the training,the group with poor performance in the pretest was significantly improved after the training,while the high group and the control group had no significant changes.At the same time,through the analysis of the resting-state fmri data,we found that after training,the connectivity between ventral attention network and salience network was strengthened,and the ventral attention network degree centrality received a significant boost.And through the selection of brain areas as ROIs,the study found the connectivity between the DLPFC and insula also got significant improvement.Based correlation analysis,the study found that changes of the connectivity within the ventral attention network and the connectivity between the ventral attention network and the salience network were correlated to the behavioral changes.In general,the study demonstrated that the nirs-based neurofeedback training had a lot of effects on the activity of multiple brain network in resting state and the potential mechanisms underlying the behavioral changes.The nirs-based neurofeedback training can effectively improve the individual conflict adaptation,and offered a causal evidence that the bilateral DLPFC is both the core of conflict adaptation.The fMRI analysis helped us find that the training induced changes on different neural network and also benefit further understanding of application and mechanism of neurofeedback training.The future study can explore the effects neurofeedback training from different modal,and explore whether it can be applied to other different cognitive abilities,which can boost our understanding and application of neurofeedback training.