Watching memory work. Translating a sentence from an unfamiliar language or figuring a math problem in your head relies on working memory -- the capacity to keep information in memory while using the information. At BU’s new Center for Memory and the Brain, several scientists are studying how this memory process operates.
Chantal Stern, a CAS associate professor of psychology, studies working memory in people using functional magnetic resonance imaging (see also “Research Briefs,” October 25, 2002, for related studies by SAR Professor Gloria Waters). CAS Psychology Professor Howard Eichenbaum studies the brains of rats as they solve complex problems. Michael Hasselmo, also a CAS psychology professor, examines the intricacies of working memory on a cellular level.
Recent studies by Hasselmo and his colleague, Angel Alonso, at the Montreal Neurological Institute and McGill University, reveal that contrary to previous expectations, individual neurons in the entorhinal cortex (an area of the brain near the hippocampus) fire single electrical impulses, or spikes, not only when they are activated by sensory input, but for several seconds after sensory input ceases. This sustained neuronal activity indicates working memory, says Hasselmo.
The researchers’ most recent studies reveal that neurons in the deep layers of the entorhinal cortex not only sustain activity, but do so at graded firing rates. If they start firing at five spikes per second (five Hz) they maintain firing at five Hz; if additional input pushes them to seven Hz, they maintain a seven Hz level, and so forth. This ability, says Hasselmo, is important for storing information about continuous dimensions, such as keeping track of compass headings and distant landmarks as you navigate a kayak, for instance.
The researchers are now examining the relationship between sustained neuronal activity and the neurochemical acetylcholine -- a substance known to activate neurons but which is depleted in the brains of individuals with Alzheimer’s disease. By better understanding the cellular processes underlying working memory, the researchers hope to find mechanisms that lead to effective treatments for Alzheimer’s disease.
This research was published in the November 14 issue of Nature. It can be found online at http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v420/n6912/abs/nature01171_fs.html.
Getting it right. Medical errors contribute to at least 44,000 deaths in the United States each year, according to a recent report published in Circulation: Journal of the American Heart Association. Medication errors make up a significant proportion of these, and the number is increasing, particularly in acute cardiac care.
Jane E. Freedman, a MED associate professor of medicine, pharmacology, and experimental therapeutics and the lead author of the report, notes that preventable medical mistakes are more frequent among elderly patients who may be suffering from a number of chronic and acute conditions for which they are taking multiple medications, making their care extremely complex.
Among the proposals offered by Freedman and her colleagues are computerized systems to report and track adverse events and to prescribe drugs. These systems may help catch potentially harmful drug interactions and suggest appropriate doses. Improved education is also needed to make physicians more conscious of drugs with similar names that can easily be confused and to keep them up to date about new medications that might require adjustments in their patients’ regimens.
Freedman advises patients to keep lists of their medications, to ask questions, and to ask for resources where they can learn more about the medications they are taking.
Briefs" is written by Joan Schwartz in the Office of the Provost. To read
more about BU research, visit http://www.bu.edu/research.