We propose to complete construction of a novel whole-head super- conducting image sensor system for Magnetoenceph-alography (MEG) of the human brain, to experimentally calibrate and validate the system using physical phantoms, and to demonstrate system efficacy by direct comparison with a commercial whole-head MEG array. A cost-effective whole-head system will provide important capabilities for non-invasive functional human brain measurements for both clinical applications and basic research. MEG directly measures a physical effect for neuronal currents with temporal resolution not limited by the sluggish vascular response; unlike PET and fMRI that measure hematological changes associated with neuronal activity. High temporal resolution is particularly important for studying neurological disorders such as epilepsy where temporal information is a major diagnostic, and for fundamental studies of synchronization and oscillatory brain activity. The whole-head MEG system proposed here has been supported by NIH during the initial project period of this grant. The system is based on the Los Alamos-patented principle of super-conducting image surface gradiometry where magnetic sources are imaged on the surface and magnetometers near this surface sense the combined fields as if the sensors were MEG systems. The whole-head MEG system design is complete; fabrication and assembly are about 90% complete. Additional key accomplishments include (A) the super-conducting imaging principle was experimentally verified; (B) comparison of niobium and lead imaging surface performance demonstrated superior performance in the lead; (C) a new cryogenic sensor support material was patented; and (D) development of novel software and analog background rejection techniques. Support is now being requested to (1) complete assembly of the whole-head MEG system will all SQUID magnetometers; (2) complete flux-locked loop design implementing our new control and background cancellation techniques; (3) implement a powerful real-time data acquisition system with data management, display and analysis; (4) use phantom measurements to test and calibrate sensitivity, imaging and noise performance, and shielding characteristics of the sensor array; (5) experimentally verify system using a sophisticated phantom; and (6) acquire experimental data for human subjects under the same conditions as NIH-funded experimental studies of the visual and somatosensory systems. The work proposed here will result in a fully functional whole-head MEG system based on new physics applications, sensors design, and fabrication techniques that promise to dramatically reduce system cost and complexity while improving system performance. Such a system will be of great value to both basic neuroscience and clinical applications.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS031052-07
Application #
6188131
Study Section
Special Emphasis Panel (ZRG7-SSS-X (07))
Program Officer
Heetderks, William J
Project Start
1992-05-01
Project End
2002-04-30
Budget Start
2000-05-01
Budget End
2001-04-30
Support Year
7
Fiscal Year
2000
Total Cost
$497,486
Indirect Cost
Name
Los Alamos National Lab
Department
Type
Organized Research Units
DUNS #
City
Los Alamos
State
NM
Country
United States
Zip Code
87545