Limitations of ex vivo measurements for in vivo neuroscience.
Author: Opitz A1,2, Falchier A3, Linn GS3, Milham MP3,2, Schroeder CE3,4,5
Affiliation:
1Center for Biomedical Imaging and Neuromodulation, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962; Alex.Opitz@nki.rfmh.org.
2Center for the Developing Brain, Child Mind Institute, New York, NY 10022.
3Center for Biomedical Imaging and Neuromodulation, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962.
4Department of Neurological Surgery, Columbia University College of Physicians and Surgeons, New York, NY 10032.
5Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY 10032.
Conference/Journal: Proc Natl Acad Sci U S A.
Date published: 2017 May 1
Other:
Pages: 201617024 , Special Notes: doi: 10.1073/pnas.1617024114. [Epub ahead of print] , Word Count: 162
A long history of postmortem studies has provided significant insight into human brain structure and organization. Cadavers have also proven instrumental for the measurement of artifacts and nonneural effects in functional imaging, and more recently, the study of biophysical properties critical to brain stimulation. However, death produces significant changes in the biophysical properties of brain tissues, making an ex vivo to in vivo comparison complex, and even questionable. This study directly compares biophysical properties of electric fields arising from transcranial electric stimulation (TES) in a nonhuman primate brain pre- and postmortem. We show that pre- vs. postmortem, TES-induced intracranial electric fields differ significantly in both strength and frequency response dynamics, even while controlling for confounding factors such as body temperature. Our results clearly indicate that ex vivo cadaver and in vivo measurements are not easily equitable. In vivo examinations remain essential to establishing an adequate understanding of even basic biophysical phenomena in vivo.
KEYWORDS: biophysical; electric field; nonhuman primate
PMID: 28461475 DOI: 10.1073/pnas.1617024114
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