The data acquired yield very large datasets that require special tools for integration, evaluation and reduction. Computer science expertise and a high performance computer cluster at the Brain Sciences Center provide the needed power to achieve these goals and define brain health in a comprehensive way.
Cognitive function is assessed using the Montreal Cognitive Assessment (MoCA). It consists of 30 questions that test visuospatial/ executive functioning, ability to name objects, memory, attention, general language skills (fluency), abstraction, delayed recall, and orientation.
Participants also are asked to provide demographic and lifestyle information. It is well-known that educational level, exercise, smoking, medical conditions such as hypertension, diabetes, and high cholesterol can affect cognitive function and increase the risk for development of dementia. Therefore, taking these factors into consideration is an important aspect of the project. The survey includes questions about alcohol, tobacco, and drug use; basic health screening; neurological testing; physical activity; nutrition; handedness, education, race, ethnicity, living situation, marital status and limitations
Structural magnetic resonance imaging (sMRI) is done to assess gray-matter volume. The data are acquired using a Philips 3T Achieva XL magnet with a SENSE 8 channel head coil. Approximately 500,000 voxels per brain are analyzed. In the first analysis, the volume of about 100 separate brain regions is calculated using FreeSurfer software (www.surfer.nmr.mgh.harvard. edu). This provides a coarse-grain, volumetric analysis of areas of the brain. In the second analysis, called voxel-based morphometry, the density of each voxel is assessed for a fine-grain analysis of each area.5 Typically, gray-matter volume decreases with age but at rates that are different for different people, for different areas of the brain, and for men and women. In that sense, one can talk about "gray-matter age" versus chronological age. A person may be 68 years old but have the gray-matter volume of a 50-year-old. Defining brain age based on measurements (as contrasted with chronological age) is a pervasive theme in this project.
MEG data are acquired while the subject is resting for one minute at 1,017 kHz using a high spatial density system with 248 axial gradiometer sensors (Magnes 3600WH, 4-D Neuroimaging, San Diego, CA). The data consist of 60,000 milliseconds x 248 sensors time series per brain. From these data, following proper prewhitening, 30,628 synchronous neural interactions (SNI) are computed between all possible pairs of sensors.
Blood is acquired for DNA and analysis of polymorphisms; associations with brain, cognitive, and language measures are investigated. DNA is assessed for specific brain-related polymorphisms that are related to cognitive function such as the alleles for apolipoprotein-E, brain-derived neurotrophic factor, and catechol- O-methyl transferase. Brain status predictions from genetics will also be investigated.