Despite Brain Damage, Working Memory Functions Within Limits

October 12, 2010 By Scott LaFee Researchers at the University of California, San Diego School of Medicine, led by Larry R. Squire, PhD, professor of psychiatry, psychology and neurosciences at UC San Diego and a scientist at the VA San Diego Healthcare System, report that working memory of relational information - where an object is located, for example - remains intact even if key brain structures like the hippocampus are damaged. The findings, published in the October 13, 2010 issue of The Journal of Neuroscience , run contrary to previous research that suggested spatial information, especially if it's linked to other kinds of information, necessarily involves the hippocampus and other regions associated with memory. Working memory is the mental ability to hold small amounts of information in an active, readily available state for a short period of time, typically a few seconds. Conversely, long-term memory involves storing a potentially unlimited amount of information for an indefinite period of time. Squire and colleagues examined four memory-impaired patients with damage to their medial temporal lobes (MTL), a region of the cerebral cortex containing the hippocampus and linked to long-term memory formation. The four patients were asked to briefly study an arrangement of objects on a table, then reproduce the objects' relative positions on another table. When the number of objects was three or less, the patients' ability to recall was similar to that of control subjects without brain damage.