The retinal nerve fiber layer is the one part of the brain where nerve cells are not covered with the fat and protein sheathing called myelin, making this assessment specific for nerve damage as opposed to brain MRI changes, which reflect an array of different types of tissue processes in the brain.

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Using the stem cells, researchers have developed cells called oligodendrocytes, which are precursors to nerve cells and which produce a protective layer around nerve cells known as myelin.

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Ann Kelley has found an even more powerful layer of control in the amygdala, a center for emotions that also has rich nerve connections to the nose.

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