Dr. J. Christopher Edgar

Principal Investigator
Associate Professor of Radiology

Dr. Edgar has over 20 years of experience using non-invasive imaging (electroencephalography (EEG), magnetoencephalography (MEG), and structural and functional MRI) to study brain function and structure in psychiatric and neurological patient populations. He is also interested in conducting the basic research needed to assess the strengths and weaknesses of neuroimaging techniques, as well as inform the development of more sophisticated analysis techniques. Over the last 5 years his research has focused on using multimodal imaging to examine the maturation of brain function and structure in adults with schizophrenia and also children with autism.

Email: EdgarJ [at] email.chop.edu (subject: Contacting%20from%20website)

Related Publications

  • 47,XYY syndrome (XYY) is a male sex chromosome disorder where individuals have an X chromosome and two copies of the Y chromosome. XYY is associated with a physical phenotype and carries increased risk of neurodevelopmental disorders such as autism spectrum disorder (ASD). Latencies of auditory evoked responses measured by magnetoencephalography have shown atypical prolongations in several neuropsychiatric and genetic disorders; specifically, delayed auditory responses have been observed in ASD. In this study, we investigated the associations of genotype and clinical phenotype with auditory processing. Whole cortex magnetoencephalography recorded during a passive auditory paradigm (500 Hz tones) was used to assess the auditory evoked response in three groups of male children: idiopathic ASD, typically developing, and XYY boys. Response waveforms were computed for left and right auditory cortex and latencies of the ∼50 ms (M50) and ∼100 ms (M100) components were determined. M50 latencies were significantly delayed compared with typically developing controls in children with ASD in the right hemisphere only, and in children with XYY in the left hemisphere only, irrespective of whether they met diagnostic criteria for ASD. Findings on the later M100 component trended in the same directions but did not attain significance, due to increased variance. Replicating previous findings, decreased M50 and M100 latencies with age were observed bilaterally. Overall, while XYY shares an electrophysiological phenotype (delayed evoked response latency) with idiopathic ASD, the hemispheric differences warrant further investigation.

  • Chen, Y., Saby, J., Kuschner, E.S., Gaetz, W., Edgar, J.C., Roberts., T.: Magnetoencephalography (MEG) of Infant Brain Development. NeuroImage. In press.
  • Matsuzaki J., Ku M., Berman JI., Blaskey L., Bloy L., Chen YH., Dell J., Edgar JC., Kuschner ES., Liu S., Saby J., Brodkin ES., Roberts TPL. Abnormal auditory mismatch fields in adults with autism spectrum disorder. Neuroscience letters, 2018, 698:140-145. Doi: 10.1016/j.neulet.2018.12.043. PMID: 30599264
  • Edgar JC., Fisk CL., Chen, Y., Stone-Howell, B., Hunter MA., Huang MX., Bustillo JR., Canive JM., Miller GA. Identifying auditory cortex encoding abnormalities in schizophrenia: The utility of low-frequency versus 40 Hz steady-state measures. Psychophysiology, 2018 Aug; 55(8): e13074. PMID: 29570815.
  • Chen Y., Stone-Howell B., Edgar JC., Huang MX., Kochunov P., Hunter MA., Wootton C., Lu BY., Bustillo J., Sadek JR., Miller GA., Canive JM. Associations and heritability of auditory encoding, gray matter, and attention in schizophrenia. Schizophrenia Bulletin, 2018 Aug; doi: 10.1093/schbul/sby111. PMID: 30099543.
  • Berman, J.I., M. Lanza, L. Blaskey, J. Edgar and T. Roberts (2013). High Angular Resolution Diffusion Imaging Probabilistic Tractography of the Auditory Radiation. American Journal of Neuroradiology 34(8): 1573-1578.
  • Berman, JI., J. C. Edgar, L. Blaskey, E. S. Kuschner, S. E. Levy, M. Ku, J. Dell and T. P. L. Roberts (2016). Multimodal Diffusion-MRI and MEG Assessment of Auditory and Language System Development in Autism Spectrum Disorder. Frontiers in Neuroanatomy 10: 30.
  • Edgar, J.C., Fisk, C.L., Chen, Y., Stone-Howell, B., Hunter, M.A., Huang, M., Bustillo, J.R., Canive, M.S., Miller, G.A. (2017). By our bootstraps: Comparing methods for measuring auditory 40 Hz steady-state neural activity. Psychophysiology, 54(8), 1110-1127. PMID: 28421620

  • Edgar, J.C., Chen, Y.H., Lanza, M., Howell, B., Chow, V.Y., Heiken, K., Liu, S., Wootton, C., Hunter, M.A., Huang, M., Miller, G.A., Cañive, J.M. (2013). Cortical thickness as a contributor to abnormal oscillations in schizophrenia? Neuroimage Clinical, 4, 122-129. PMID: 24371794