Toward a brain functional connectivity mapping modality by simultaneous imaging of coherent brainwaves.
Matching the proton-magnetic-resonance frequency to the frequency of a periodic neural oscillation (e.g., alpha or gamma band waves) by magnetic resonance imaging techniques, enables direct visualization of brain functional connectivity. Functional connectivity has been studied by analyzing the correlation between coherent neural oscillations in different areas of the brain. In electro- or magneto-encephalography, coherent source reconstruction in a source-space is very tricky due to power leaking from the correlation among the sources. For this reason, most studies have been limited to sensor-space analyses, which give doubtful results because of volume current mixing. The direct visualization of coherent brain oscillations can circumvent this problem. The feasibility of this idea was demonstrated by conducting phantom experiments with a SQUID-based, micro-Tesla NMR/MRI system. We introduce an experimental trick, an effective step-up of the measurement B-field in a pulse sequence, to decouple the magnetic resonance signal from the strong magneto-encephalographic signal at the same frequency.
Center for Brain and Cognition Measurement, Korea Research Institute of Standards and Science (KRISS), Doryong-dong, Yuseong-gu, Daejeon 305-340, Republic of Korea. Electronic address: kwkim@kriss.re.kr.
Kiwoong
K
Kim
Center for Brain and Cognition Measurement, Korea Research Institute of Standards and Science (KRISS), Doryong-dong, Yuseong-gu, Daejeon 305-340, Republic of Korea.
Seong-Joo
SJ
Lee
Center for Brain and Cognition Measurement, Korea Research Institute of Standards and Science (KRISS), Doryong-dong, Yuseong-gu, Daejeon 305-340, Republic of Korea.
Chan Seok
CS
Kang
Center for Brain and Cognition Measurement, Korea Research Institute of Standards and Science (KRISS), Doryong-dong, Yuseong-gu, Daejeon 305-340, Republic of Korea.
Seong-Min
SM
Hwang
Center for Brain and Cognition Measurement, Korea Research Institute of Standards and Science (KRISS), Doryong-dong, Yuseong-gu, Daejeon 305-340, Republic of Korea.
Yong-Ho
YH
Lee
Center for Brain and Cognition Measurement, Korea Research Institute of Standards and Science (KRISS), Doryong-dong, Yuseong-gu, Daejeon 305-340, Republic of Korea.
Kwon-Kyu
KK
Yu
D000465:Algorithms; D000513:Alpha Rhythm / Q000502:physiology; D001931:Brain Mapping / Q000379:methods*; D058256:Brain Waves / Q000502:physiology*; D004569:Electroencephalography; D004574:Electromagnetic Fields; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods*; D008280:Magnetics; D015225:Magnetoencephalography; D009434:Neural Pathways / Q000502:physiology*; D019047:Phantoms, Imaging
Biomagnetic resonance; Brain functional connectivity; MRI; NMR; SQUID