EEG Functional Connectivity Patterns Over the Course of Neurofeedback Attention Training for Healthy Subjects: A Pilot Study

Neurofeedback (NFB) training has been applied as a complementary or alternative treatment to several neurological conditions, such as attention deficit and hyperactivity, epilepsy, anxiety, amongst others. However, the technique has yielded controversial findings, mainly due to non-standardized and uncontrolled studies. Moreover, research indicating apparent benefits of NFB training often do not investigate how the observed behavior changes relate to subjacent neural mechanisms. In this study, our aim was to verify whether measures of functional connectivity (FC) changed with the NFB training sessions, and if such variations could be related to the subject's subjective perception of their attention capacity. We analyzed electroencephalography (EEG) data during the resting state (RS) condition for three healthy subjects over 10 NFB sessions and assumed that there are individual, specific sets of FC links that remain for, at least, a certain fraction r of the total RS recording. By setting r = 0.7, we computed the number of these frequent links over the NFB sessions. Overall, we found that pre and post-NFB training RS recordings tend to present distinct patterns, and that there can be specific increasing or decreasing trends for each subject. On the other hand, no correlations were found between the FC results and the subjects' answers regarding their subjective perception of attention. Inclusion of more subjects and other experimental groups, such as control and/or false-NFB, will be performed next to provide more certain insights.