title: The frequency and reliability of cortical activity using a novel strategy to present pressure pain stimulus over the lumbar spine.
abstract: BACKGROUND
  The blocked stimulus presentation strategy, in fMRI study designs, is an important means to study brain function related to a particular stimulus. Specifically, applying pressure stimuli perceived as painful to different anatomical regions has been used to improve our understanding of central sensitization, which is an important clinical phenomenon in chronic pain.
  
  
  METHODS
  This paper introduces a novel MR-compatible device used to apply pressure pain stimuli to the lumbar spine of 13 subjects in the supine position. We present the frequency of individuals and within-subject reliability of cortical activity in the following brain regions: the primary somatosensory cortex, insula and anterior cingulate cortex bilaterally.
  
  
  RESULTS
  Using the novel MR-compatible device, a high frequency of individuals showed cortical activity within the a priori brain regions. There was good to excellent run-to-run reliability for peak voxel, while cluster size was less reliable. We found a higher than expected association between stimulus presentation and movement artifacts.
  
  
  CONCLUSIONS
  Unlike previous methods, the current strategy can apply pressure stimuli to subjects over the lumbar spine while they lay supine. Previous methods required subjects to lay prone.
  
  
  CONCLUSIONS
  This strategy could be used for evaluating pressure stimuli related central sensitization associated with back pain.
authors.affiliation: Rehabilitation Science Program, University of Florida, Gainesville, FL, USA. Electronic address: chaz.gay@phhp.ufl.edu.
authors.forename: Charles W
authors.initials: CW
authors.lastname: Gay
authors.affiliation: Department of Research, New York Chiropractic College, Seneca Falls, NY, USA. Electronic address: opapuga@nycc.edu.
authors.forename: Mark O
authors.initials: MO
authors.lastname: Papuga
authors.affiliation: Department of Physical Therapy, College of Public Health and Health Professions, University of Florida, Gainesville, FL, USA. Electronic address: bish@phhp.ufl.edu.
authors.forename: Mark D
authors.initials: MD
authors.lastname: Bishop
authors.affiliation: Department of Research, New York Chiropractic College, Seneca Falls, NY, USA; Department of Orthopedics, School of Medicine, University of Rochester, Rochester, NY, USA; Canadaigua VA Medical Center, Canadaigua, NY, USA. Electronic address: Paul.Dougherty@va.gov.
authors.forename: Paul
authors.initials: P
authors.lastname: Dougherty
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000098:blood supply / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008159:Lumbar Vertebrae; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010146:Pain / Q000209:etiology* / Q000473:pathology*; D010147:Pain Measurement; D011312:Pressure / Q000009:adverse effects*; D011601:Psychophysics; D015203:Reproducibility of Results
chemical_list: D010100:Oxygen
keywords: Back pain; Pain processing; Pressure pain; Reliability; fMRI