Links in the Brain

In Mice, the Frontal Cortex Has Ties to the Immune System

by Patricia McBroom

Berkeley neuroscientists have discovered what they believe is a basic mechanism through which higher brain centers in mammals may help to regulate the immune system.

The experiments on mice involve the frontal cortex, which is the most evolved structure in the brain, responsible for voluntary, purposeful behavior. It appears that this region has a direct link with the thymus gland, which is the production center for germ-fighting T-cells, and may be able to modulate levels of CD4 and CD8 T-cells.

While it is too early to comment on any clinical applications, the researchers said their discovery, based on 10 years of research, brings together several different lines of evidence all pointing to one conclusion.

"I think we have the mechanism for showing that there is voluntary control over the immune system," said Marian Diamond, professor of integrative biology. She said the frontal cortex of the mouse is comparable to the prefrontal lobes and the motor cortex of the human brain combined. Consequently, the human equivalent to the mouse brain would include both purposeful movement, such as exercising, and planning ahead or forethought.

Both might be playing a role in regulating functions of the immune system, she said.

Diamond headed the research carried out by Gary O. Gaufo, now a postdoctoral fellow in immunology at UCSF.

They recently published a joint paper in the journal Brain Research involving implantation of a thymus in young mice genetically bred to be immune deficient because they are born without a thymus.

The scientists were able to show major effects on the forebrain of the animals due to implantation of the thymus beneath the capsule of the kidneys. The cerebral cortex of this strain of immune deficient mice is typically abnormally thin and underdeveloped. But in the mice Gaufo altered, the frontal area became as thick as normal. It was the only part of the brain to show such changes.



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