October 21, 2013. The decrease in the size of the hippocampus, a seahorse-shaped brain area involved in memory, is related to the levels of a major brain chemical called glutamate, according to a new study published online October 9, 2013, in JAMA Psychiatry, of schizophrenia patients.
Researchers, led by Adrienne Lahti from the University of Alabama at Birmingham, used two different types of brain imaging to examine the size of the hippocampus and measure its glutamate levels. Compared to healthy controls, people with schizophrenia had a smaller hippocampus as well as higher glutamate levels, and the two were related. The more glutamate in a person’s hippocampus, the smaller the brain region was. No relationship between hippocampus size and glutamate levels was found in control subjects. Too much glutamate is toxic to cells, so the findings suggest that the elevated glutamate levels in the hippocampus may be responsible for the reduced hippocampal size. (For more details, see SRF related news story.)—Allison A. Curley.