title: Functional connectivity of the cortical swallowing network in humans.
abstract: BACKGROUND
  Coherent fluctuations of blood oxygenation level dependent (BOLD) signal have been referred to as "functional connectivity" (FC). Our aim was to systematically characterize FC of underlying neural network involved in swallowing, and to evaluate its reproducibility and modulation during rest or task performance.
  
  
  METHODS
  Activated seed regions within known areas of the cortical swallowing network (CSN) were independently identified in 16 healthy volunteers. Subjects swallowed using a paradigm driven protocol, and the data analyzed using an event-related technique. Then, in the same 16 volunteers, resting and active state data were obtained for 540 s in three conditions: 1) swallowing task; 2) control visual task; and 3) resting state; all scans were performed twice. Data was preprocessed according to standard FC pipeline. We determined the correlation coefficient values of member regions of the CSN across the three aforementioned conditions and compared between two sessions using linear regression. Average FC matrices across conditions were then compared.
  
  
  RESULTS
  Swallow activated twenty-two positive BOLD and eighteen negative BOLD regions distributed bilaterally within cingulate, insula, sensorimotor cortex, prefrontal and parietal cortices. We found that: 1) Positive BOLD regions were highly connected to each other during all test conditions while negative BOLD regions were tightly connected among themselves; 2) Positive and negative BOLD regions were anti-correlated at rest and during task performance; 3) Across all three test conditions, FC among the regions was reproducible (r>0.96, p<10(-5)); and 4) The FC of sensorimotor region to other regions of the CSN increased during swallowing scan.
  
  
  CONCLUSIONS
  1) Swallow activated cortical substrates maintain a consistent pattern of functional connectivity; 2) FC of sensorimotor region is significantly higher during swallow scan than that observed during a non-swallow visual task or at rest.
authors: Gastroenterology and Hepatology, Department of Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
authors: Arash
authors: A
authors: Babaei
authors: B Douglas
authors: BD
authors: Ward
authors: Robert M
authors: RM
authors: Siwiec
authors: Shahryar
authors: S
authors: Ahmad
authors: Mark
authors: M
authors: Kern
authors: Andrew
authors: A
authors: Nencka
authors: Shi-Jiang
authors: SJ
authors: Li
authors: Reza
authors: R
authors: Shaker
mesh_terms: D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology*; D003679:Deglutition / Q000502:physiology*; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009434:Neural Pathways / Q000502:physiology*; D055815:Young Adult