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fMRIs reveal more brain secrets, the default-mode network enables to hold the low-priority idea in abeyance until a time when busy with something else.

"The default-mode network appears to be the brain's back burner for social decision making," said Peter T. Fox, M.D., director of the Research Imaging Institute at The University of Texas Health Science Center at San Antonio. "Usually these back-burner ideas relate to interpersonal interactions and decisions that can't readily be quantified and shouldn't be rushed."

Dr. Fox likened this to putting a computer batch job into background processing to wait until the system is less busy.

A recently released study from the Research Imaging Institute, the Southwest Foundation for Biomedical Research and other institutions offers evidence that genetics plays a role in this back-burner setup, which has been shown to be abnormal in a variety of psychiatric disorders.

The default-mode network is one of several neural networks that operate whether the mind is at rest or is occupied doing a task.

The newer research estimated the importance of genetic effects on the default-mode network by creating maps of eight anatomically distinct regions within the network. These maps were obtained by functional magnetic resonance imaging (fMRI) studies in 333 individuals from 29 randomly selected, extended-family pedigrees.

Network connectivity and gray-matter density were correlated to genetic factors. "We found that more than 40 percent of the between-subject variance in functional connectivity within the default-mode network was under genetic control," Dr. Fox said.

Based on this information, it is possible new diagnostic tools could be considered for various psychiatric or neurological illnesses, he said.

The study also included collaborators from the Yale University School of Medicine, the University of Oxford in Oxford, U.K., and Imperial College in London, U.K. The project is an outgrowth of longstanding collaborations between the UT Health Science Center and the Southwest Foundation for Biomedical Research using tools for gene discovery. It is also a result of substantial collaborations between the Research Imaging Institute and Oxford to develop novel applications of imaging methods.

Source: UT Health Science Center

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