title: The dynamic dielectric at a brain functional site and an EM wave approach to functional brain imaging.
abstract: Functional brain imaging has tremendous applications. The existing methods for functional brain imaging include functional Magnetic Resonant Imaging (fMRI), scalp electroencephalography (EEG), implanted EEG, magnetoencephalography (MEG) and Positron Emission Tomography (PET), which have been widely and successfully applied to various brain imaging studies. To develop a new method for functional brain imaging, here we show that the dielectric at a brain functional site has a dynamic nature, varying with local neuronal activation as the permittivity of the dielectric varies with the ion concentration of the extracellular fluid surrounding neurons in activation. Therefore, the neuronal activation can be sensed by a radiofrequency (RF) electromagnetic (EM) wave propagating through the site as the phase change of the EM wave varies with the permittivity. Such a dynamic nature of the dielectric at a brain functional site provides the basis for an RF EM wave approach to detecting and imaging neuronal activation at brain functional sites, leading to an RF EM wave approach to functional brain imaging.
authors.affiliation: Neuroengineering Lab, National University of Singapore, 9 Engineering Drive 1, Singapore 117575.
authors.forename: X P
authors.initials: XP
authors.lastname: Li
authors.affiliation: Newrocare Pte Ltd, 6 EU Tong Sen Street, #12-03, The Central, Singapore 059817.
authors.forename: Q
authors.initials: Q
authors.lastname: Xia
authors.affiliation: Neuroengineering Lab, National University of Singapore, 9 Engineering Drive 1, Singapore 117575.
authors.forename: D
authors.initials: D
authors.lastname: Qu
authors.affiliation: Neuroengineering Lab, National University of Singapore, 9 Engineering Drive 1, Singapore 117575.
authors.forename: T C
authors.initials: TC
authors.lastname: Wu
authors.affiliation: Guilin University of Electronic Technology, No.1 Jinji Road, Guilin 541004, Guangxi, P.R. China.
authors.forename: D G
authors.initials: DG
authors.lastname: Yang
authors.affiliation: Guilin University of Electronic Technology, No.1 Jinji Road, Guilin 541004, Guangxi, P.R. China.
authors.forename: W D
authors.initials: WD
authors.lastname: Hao
authors.affiliation: Guilin University of Electronic Technology, No.1 Jinji Road, Guilin 541004, Guangxi, P.R. China.
authors.forename: X
authors.initials: X
authors.lastname: Jiang
authors.affiliation: Guilin University of Electronic Technology, No.1 Jinji Road, Guilin 541004, Guangxi, P.R. China.
authors.forename: X M
authors.initials: XM
authors.lastname: Li
mesh_terms: D000818:Animals; D001921:Brain / Q000502:physiology*; D003198:Computer Simulation; D004574:Electromagnetic Fields; D059907:Functional Neuroimaging / Q000379:methods*; D009474:Neurons / Q000502:physiology; D017207:Rats, Sprague-Dawley; D009435:Synaptic Transmission