title: Artemis 123: development of a whole-head infant and young child MEG system.
abstract: BACKGROUND
  A major motivation in designing the new infant and child magnetoencephalography (MEG) system described in this manuscript is the premise that electrophysiological signatures (resting activity and evoked responses) may serve as biomarkers of neurodevelopmental disorders, with neuronal abnormalities in conditions such as autism spectrum disorder (ASD) potentially detectable early in development. Whole-head MEG systems are generally optimized/sized for adults. Since magnetic field produced by neuronal currents decreases as a function of distance(2) and infants and young children have smaller head sizes (and thus increased brain-to-sensor distance), whole-head adult MEG systems do not provide optimal signal-to-noise in younger individuals. This spurred development of a whole-head infant and young child MEG system - Artemis 123.
  
  
  METHODS
  In addition to describing the design of the Artemis 123, the focus of this manuscript is the use of Artemis 123 to obtain auditory evoked neuromagnetic recordings and resting-state data in young children. Data were collected from a 14-month-old female, an 18-month-old female, and a 48-month-old male. Phantom data are also provided to show localization accuracy.
  
  
  RESULTS
  Examination of Artemis 123 auditory data showed generalizability and reproducibility, with auditory responses observed in all participants. The auditory MEG measures were also found to be manipulable, exhibiting sensitivity to tone frequency. Furthermore, there appeared to be a predictable sensitivity of evoked components to development, with latencies decreasing with age. Examination of resting-state data showed characteristic oscillatory activity. Finally, phantom data showed that dipole sources could be localized with an error less than 0.5 cm.
  
  
  CONCLUSIONS
  Artemis 123 allows efficient recording of high-quality whole-head MEG in infants four years and younger. Future work will involve examining the feasibility of obtaining somatosensory and visual recordings in similar-age children as well as obtaining recordings from younger infants. Thus, the Artemis 123 offers the promise of detecting earlier diagnostic signatures in such neurodevelopmental disorders.
authors.affiliation: Department of Radiology, Lurie Family Foundations MEG Imaging Center, The Children's Hospital of Philadelphia Philadelphia, PA, USA.
authors.forename: Timothy P L
authors.initials: TP
authors.lastname: Roberts
authors.affiliation: Tristan Technologies, Inc., San Diego, CA, USA.
authors.forename: Douglas N
authors.initials: DN
authors.lastname: Paulson
authors.affiliation: Tristan Technologies, Inc., San Diego, CA, USA.
authors.forename: Eugene
authors.initials: E
authors.lastname: Hirschkoff
authors.affiliation: Tristan Technologies, Inc., San Diego, CA, USA.
authors.forename: Kevin
authors.initials: K
authors.lastname: Pratt
authors.affiliation: Tristan Technologies, Inc., San Diego, CA, USA.
authors.forename: Anthony
authors.initials: A
authors.lastname: Mascarenas
authors.affiliation: Tristan Technologies, Inc., San Diego, CA, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Miller
authors.affiliation: Tristan Technologies, Inc., San Diego, CA, USA.
authors.forename: Mengali
authors.initials: M
authors.lastname: Han
authors.affiliation: Tristan Technologies, Inc., San Diego, CA, USA.
authors.forename: Jason
authors.initials: J
authors.lastname: Caffrey
authors.affiliation: Tristan Technologies, Inc., San Diego, CA, USA.
authors.forename: Chuck
authors.initials: C
authors.lastname: Kincade
authors.affiliation: Tristan Technologies, Inc., San Diego, CA, USA.
authors.forename: Bill
authors.initials: B
authors.lastname: Power
authors.affiliation: Department of Radiology, Lurie Family Foundations MEG Imaging Center, The Children's Hospital of Philadelphia Philadelphia, PA, USA.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Murray
authors.affiliation: Department of Radiology, Lurie Family Foundations MEG Imaging Center, The Children's Hospital of Philadelphia Philadelphia, PA, USA.
authors.forename: Vivian
authors.initials: V
authors.lastname: Chow
authors.affiliation: Department of Radiology, Lurie Family Foundations MEG Imaging Center, The Children's Hospital of Philadelphia Philadelphia, PA, USA.
authors.forename: Charlie
authors.initials: C
authors.lastname: Fisk
authors.affiliation: Department of Radiology, Lurie Family Foundations MEG Imaging Center, The Children's Hospital of Philadelphia Philadelphia, PA, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Ku
authors.affiliation: Department of Radiology, Lurie Family Foundations MEG Imaging Center, The Children's Hospital of Philadelphia Philadelphia, PA, USA.
authors.forename: Darina
authors.initials: D
authors.lastname: Chudnovskaya
authors.affiliation: Department of Radiology, Lurie Family Foundations MEG Imaging Center, The Children's Hospital of Philadelphia Philadelphia, PA, USA.
authors.forename: John
authors.initials: J
authors.lastname: Dell
authors.affiliation: Department of Radiology, Lurie Family Foundations MEG Imaging Center, The Children's Hospital of Philadelphia Philadelphia, PA, USA.
authors.forename: Rachel
authors.initials: R
authors.lastname: Golembski
authors.affiliation: Department of Radiology, Lurie Family Foundations MEG Imaging Center, The Children's Hospital of Philadelphia Philadelphia, PA, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Lam
authors.affiliation: Department of Radiology, Lurie Family Foundations MEG Imaging Center, The Children's Hospital of Philadelphia Philadelphia, PA, USA.
authors.forename: Lisa
authors.initials: L
authors.lastname: Blaskey
authors.affiliation: Department of Radiology, Lurie Family Foundations MEG Imaging Center, The Children's Hospital of Philadelphia Philadelphia, PA, USA.
authors.forename: Emily
authors.initials: E
authors.lastname: Kuschner
authors.affiliation: Department of Radiology, Lurie Family Foundations MEG Imaging Center, The Children's Hospital of Philadelphia Philadelphia, PA, USA.
authors.forename: Luke
authors.initials: L
authors.lastname: Bloy
authors.affiliation: Department of Radiology, Lurie Family Foundations MEG Imaging Center, The Children's Hospital of Philadelphia Philadelphia, PA, USA.
authors.forename: William
authors.initials: W
authors.lastname: Gaetz
authors.affiliation: Department of Radiology, Lurie Family Foundations MEG Imaging Center, The Children's Hospital of Philadelphia Philadelphia, PA, USA.
authors.forename: J Christopher
authors.initials: JC
authors.lastname: Edgar
keywords: auditory; infant; magnetoencephalography; resting-state; young child