title: The Impact of Alzheimer's Disease on the Resting State Functional Connectivity of Brain Regions Modulating Pain: A Cross Sectional Study.
abstract: It is currently unknown why people with Alzheimer's disease (AD) receive less pain medication and report pain less frequently.
  
  
  
  The purpose of this study was to determine the impact of AD on thermal psychophysics and resting-state functional connectivity (RSFC) among sensory, affective, descending modulatory, and default mode structures.
  
  
  
  Controls (n = 23, 13 = female) and age-matched people with AD (n = 23, 13 = females) underwent psychophysical testing to rate perceptions of warmth, mild, and moderate pain and then completed resting-state fMRI. Between groups analysis in psychophysics and RSFC were conducted among pre-defined regions of interest implicated in sensory and affective dimensions of pain, descending pain modulation, and the default mode network.
  
  
  
  People with AD displayed higher thermal thresholds for warmth and mild pain but similar moderate pain thresholds to controls. No between-group differences were found for unpleasantness at any percept. Relative to controls, people with AD demonstrated reduced RSFC between the right posterior insula and left anterior cingulate and also between right amygdala and right secondary somatosensory cortex. Moderate pain unpleasantness reports were associated with increased RSFC between right dorsolateral prefrontal cortex and left ACC in controls only.
  
  
  
  While AD had little effect on unpleasantness, people with AD had increased thermal thresholds, altered RSFC, and no association of psychophysics with RSFC in pain regions. Findings begin to elucidate that in people with AD, altered integration of pain sensation, affect, and descending modulation may, in part, contribute to decreased verbal pain reports and thus decreased analgesic administration.
authors.affiliation: School of Nursing, Vanderbilt University, Nashville, TN, USA.|Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA.|Psychiatric Neuroimaging Program, Vanderbilt University Medical Center, Nashville, TN, USA.|Department of Psychiatry and Behavioral Sciences, Vanderbilt University, Nashville, TN, USA.
authors.forename: Todd B
authors.initials: TB
authors.lastname: Monroe
authors.affiliation: Department of Neurology & Ophthalmology, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, USA.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Beach
authors.affiliation: School of Medicine, Vanderbilt University, Nashville, TN, USA.
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Bruehl
authors.affiliation: School of Nursing, Vanderbilt University, Nashville, TN, USA.|School of Medicine, Vanderbilt University, Nashville, TN, USA.
authors.forename: Mary S
authors.initials: MS
authors.lastname: Dietrich
authors.affiliation: Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA.
authors.forename: Baxter P
authors.initials: BP
authors.lastname: Rogers
authors.affiliation: Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA.
authors.forename: John C
authors.initials: JC
authors.lastname: Gore
authors.affiliation: School of Nursing, Vanderbilt University, Nashville, TN, USA.|Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA.|Psychiatric Neuroimaging Program, Vanderbilt University Medical Center, Nashville, TN, USA.
authors.forename: Sebastian W
authors.initials: SW
authors.lastname: Atalla
authors.affiliation: Psychiatric Neuroimaging Program, Vanderbilt University Medical Center, Nashville, TN, USA.|School of Medicine, Vanderbilt University, Nashville, TN, USA.
authors.forename: Ronald L
authors.initials: RL
authors.lastname: Cowan
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001921:Brain / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001931:Brain Mapping; D003430:Cross-Sectional Studies; D005260:Female; D006358:Hot Temperature; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009434:Neural Pathways / Q000000981:diagnostic imaging / Q000503:physiopathology; D010146:Pain / Q000503:physiopathology*; D010147:Pain Measurement; D017288:Pain Threshold; D011601:Psychophysics; D012146:Rest
keywords: Acute pain; Alzheimer’s disease; brain mapping; dementia; experimental thermal pain; functional connectivity; neurobiology; neuroimaging; pain perception; pain threshold; psychophysics