The low-frequency BOLD signal oscillation response in the insular associated to immediate analgesia of ankle acupuncture in patients with chronic low back pain

Anfeng Xiang,1,* Yang Yu,2,* Xize Jia,3,4 Huibin Ma,5,6 Hui Liu,1 Yu Zhang,1 Jun Rong,7,* Sheng Liu1,* 1School of Acupuncture-Moxibustion and Tuina, Shanghai University of Traditional Chinese Medicine, Shanghai, China; 2Department of Psychiatry, the Second Affiliated Hospital of Zhejiang University School of Medicine, Zhejiang, China; 3Center for Cognition and Brain Disorders, Institutes of Psychological Sciences, Hangzhou Normal University, Zhejiang, China; 4Zhejiang Key Laboratory for Research in Assessment of Cognitive Impairments, Zhejiang, China; 5School of Information and Electronics Technology, Jiamusi University, Heilongjiang, China; 6Integrated Medical Research School, Jiamusi University, Heilongjiang, China; 7Department of Sports Rehabilitation, Hangzhou Red Cross Hospital, Zhejiang, China *These authors contributed equally to this work Purpose: The present study evaluated the modulation effect of a painless acupuncture technique, ankle acupuncture (AA), on resting-state functional change in patients with chronic low back pain (CLBP). Patients and methods: Fourteen participants diagnosed with CLBP received AA and underwent one brain functional image scan after tactile stimulation and another one following the insertion of the needle. The needling sensations and clinical pain intensities were evaluated after the end of each functional image scan. The significance levels of Visual Analog Scales/Scores (VASs) before and after acupuncture were determined using paired t-test. The brain areas showing differences in the amplitude of low-frequency fluctuation (ALFF) and fractional ALFF (fALFF) between the two scans were identified. We also explored the relationship between mean ALFF values in brain areas identified and VAS scores based on Pearson correlation coefficient. Results: A complete-case analysis was performed on 12 participants. Neither different needling sensations nor any local sensations during the two scans was found. The clinical findings indicated t