81.   Dr. Manuelidis suspects these mice had brain damage because the mutated prion protein injured their brain cells, but that they did not in fact have scrapie.

82.   Dopamine is a neurotransmitter, a molecule released by one brain cell in order to signal another.

83.   Dr. Lorenz Studer at Sloan-Kettering converted the embryonic cells into brain cells.

84.   Earlier research at Johns Hopkins University Hospital proposed that glutamate, an amino acid responsible for carrying messages between brain cells, may be involved.

85.   Dopamine is a chemical known as a neurotransmitter, one of many that help brain cells communicate with one another.

86.   Dopamine is a neurotransmitter, a molecule released by one brain cell to signal another.

87.   Early on, brain cells are not well connected, McClelland said.

88.   During a stroke, the death of brain cells triggers chemical and electrical processes that damage surrounding brain tissue.

89.   Evan Snyder of Harvard Medical School in Boston has also made progress in using stem cells to kill off cancerous brain cells.

90.   Ecstasy enters the bloodstream like Prozac and similarly strikes at those brain cells that release serotonin, a chemical that regulates mood.