title: Immediate changes after manual therapy in resting-state functional connectivity as measured by functional magnetic resonance imaging in participants with induced low back pain.
abstract: OBJECTIVE
  The purposes of this study were to use functional magnetic resonance imaging to investigate the immediate changes in functional connectivity (FC) between brain regions that process and modulate the pain experience after 3 different types of manual therapies (MT) and to identify reductions in experimentally induced myalgia and changes in local and remote pressure pain sensitivity.
  
  
  METHODS
  Twenty-four participants (17 men; mean age ± SD, 21.6 ± 4.2 years) who completed an exercise-injury protocol to induce low back pain were randomized into 3 groups: chiropractic spinal manipulation (n = 6), spinal mobilization (n = 8), or therapeutic touch (n = 10). The primary outcome was the immediate change in FC as measured on functional magnetic resonance imaging between the following brain regions: somatosensory cortex, secondary somatosensory cortex, thalamus, anterior and posterior cingulate cortices, anterior and poster insula, and periaqueductal gray. Secondary outcomes were immediate changes in pain intensity, measured with a 101-point numeric rating scale, and pain sensitivity, measured with a handheld dynamometer. Repeated-measures analysis of variance models and correlation analyses were conducted to examine treatment effects and the relationship between within-person changes across outcome measures.
  
  
  RESULTS
  Changes in FC were found between several brain regions that were common to all 3 MT interventions. Treatment-dependent changes in FC were also observed between several brain regions. Improvement was seen in pain intensity after all interventions (P < .05) with no difference between groups (P > .05). There were no observed changes in pain sensitivity, or an association between primary and secondary outcome measures.
  
  
  CONCLUSIONS
  These results suggest that MTs (chiropractic spinal manipulation, spinal mobilization, and therapeutic touch) have an immediate effect on the FC between brain regions involved in processing and modulating the pain experience. This suggests that neurophysiologic changes after MT may be an underlying mechanism of pain relief.
authors.affiliation: Postdoctoral Research Fellow, Rehabilitation Science, College of Public and Health and Health Professions, University of Florida, Gainesville, Fla. Electronic address: chaz.gay@ufl.edu.
authors.forename: Charles W
authors.initials: CW
authors.lastname: Gay
authors.affiliation: Professor, Department of Clinical and Health Psychology, College of Public and Health and Health Professions, University of Florida, Gainesville, FL.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Robinson
authors.affiliation: Associate Professor and Assistant Department Chair, Department of Physical Therapy, College of Public and Health and Health Professions, University of Florida, Gainesville, FL.
authors.forename: Steven Z
authors.initials: SZ
authors.lastname: George
authors.affiliation: Associate Professor, Department of Clinical and Health Psychology, College of Public and Health and Health Professions, University of Florida, Gainesville, FL; Research Health Scientist, VA RR&D Brain Rehabilitation Research Center of Excellence (151A), Malcom Randall Veterans Administration Medical Center, Gainesville, FL.
authors.forename: William M
authors.initials: WM
authors.lastname: Perlstein
authors.affiliation: Associate Professor, Department of Physical Therapy, College of Public and Health and Health Professions, University of Florida, Gainesville, FL.
authors.forename: Mark D
authors.initials: MD
authors.lastname: Bishop
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000175:diagnosis* / Q000534:rehabilitation*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D026882:Manipulation, Chiropractic / Q000379:methods*; D026301:Manipulation, Osteopathic / Q000379:methods*; D020393:Manipulation, Spinal / Q000379:methods*; D008962:Models, Theoretical; D010147:Pain Measurement / Q000379:methods; D058748:Pain Perception / Q000502:physiology; D017288:Pain Threshold / Q000502:physiology; D012307:Risk Factors; D016037:Single-Blind Method; D013997:Time Factors; D016896:Treatment Outcome; D014838:Volunteers; D055815:Young Adult
keywords: Chiropractic; Magnetic Resonance Imaging; Musculoskeletal Manipulations; Neurophysiology Brain