title: Functional magnetic resonance imaging of the primary somatosensory cortex in piglets.
abstract: OBJECTIVE
  The piglet is an excellent model for the developing human brain, and has been used increasingly in various centers for studies of traumatic brain injury and other insults. Unlike rodent or primate models, however, there are few behavioral scales for the piglet, and the available ones are used to test general responsiveness rather than specific functional outcome. The differing behavioral repertoires of animals of different ages provide an additional challenge when age-dependent injury responses are compared. To overcome these experimental limitations of piglets in brain injury research, the authors developed a functional magnetic resonance (fMR) imaging paradigm that can be used to track recovery in the somatosensory cortex over time in anesthetized animals of different ages.
  
  
  METHODS
  Fifteen fMR imaging studies in eight piglets were performed before and after scaled cortical impact injury to the primary somatosensory cortex subserving snout sensation. Specific anesthetic and imaging protocols enabled visualization of cortical activation, and comparison with somatosensory evoked potentials obtained before and after injury was obtained. A piglet brain template for group-level analysis of these data was constructed, similar to the fMR imaging techniques used in humans, to allow for group comparisons and longitudinal change analysis over time.
  
  
  CONCLUSIONS
  Loss of function in a specifically traumatized cortical region and its subsequent recovery over time can now be demonstrated visually by fMR imaging in the piglet. Besides its value in understanding intrinsic recovery mechanisms and plasticity at different ages, this functional outcome measure will enable the use of the piglet model in treatment trials specifically designed for the immature brain.
authors.affiliation: Department of Pediatric Neurosurgery, Children's Hospital at Dartmouth, Dartmouth Hitchcock Medical Center and Dartmouth Medical School, Lebanon, New Hampshire 03756, USA. acd@hitchcock.org
authors.forename: Ann-Christine
authors.initials: AC
authors.lastname: Duhaime
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Saykin
authors.forename: Brenna C
authors.initials: BC
authors.lastname: McDonald
authors.forename: Carter P
authors.initials: CP
authors.lastname: Dodge
authors.forename: Clifford J
authors.initials: CJ
authors.lastname: Eskey
authors.forename: Terrance M
authors.initials: TM
authors.lastname: Darcey
authors.forename: Loretta L
authors.initials: LL
authors.lastname: Grate
authors.forename: Paul
authors.initials: P
authors.lastname: Tomashosky
mesh_terms: D000367:Age Factors; D000818:Animals; D001931:Brain Mapping; D002648:Child; D004195:Disease Models, Animal; D004292:Dominance, Cerebral / Q000502:physiology; D017352:Echo-Planar Imaging; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D016489:Head Injuries, Closed / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D020127:Recovery of Function / Q000502:physiology*; D013003:Somatosensory Cortex / Q000293:injuries* / Q000473:pathology / Q000503:physiopathology; D013552:Swine