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Frequency Dependent Electromagnetic Fields: Models Appropriate for the Brain


Leong, Harrison Mon Fook (1986) Frequency Dependent Electromagnetic Fields: Models Appropriate for the Brain. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/TNQ6-P071.


This dissertation addresses the problem of modeling electromagnetic fields in and about the brain-skull-scalp system that are generated by active neural populations. Specifically, frequency dependence of Maxwell's fields is explored for the case of a dipole-like current source embedded in a spherical conductor surrounded by a vacuum. Frequency dependence was found to be small. Loosely, the difference between frequency dependent and frequency independent fields reached approximately 1% at 103 Hz and reached up to 16% at 104 Hz. Frequency dependence was found to be highly dependent on conductivity, the size of the conductor, and on the phase of generated fields. These findings indicate that the degree to which the magnetic field is coupled to the electric field depends on interference patterns occurring within the conductor. Several highly distinguishable exceptions to general trends in the data were found to be consistent with this view.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Electromagnetic, brain models, dipole models, neural activity, surface integration, fredholm equation of the second kind
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Bioinformation Systems
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Fender, Derek H.
Thesis Committee:
  • Fender, Derek H. (chair)
  • Barr, Alan H.
  • Kreiss, Heinz-Otto
  • Hestenes, John
  • Hamilton, Charles R.
Defense Date:27 December 1985
Funding AgencyGrant Number
Record Number:CaltechETD:etd-03192008-111015
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:1018
Deposited By: Imported from ETD-db
Deposited On:27 Mar 2008
Last Modified:20 Dec 2019 19:33

Thesis Files

PDF (Leong_hmf_1986.pdf) - Final Version
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