Animal memories. When Fido greets you at the door, does he actually remember that you fed him that morning and took him for a walk? Philosophers and psychologists have long pondered whether animals have recollective memory — the kind of memory that enables humans to remember specific details about people and events — as opposed to recognition, or the feeling that you’ve seen someone or something before.
Although Aristotle believed recollection to be a purely human faculty, researchers at the Center for Memory and Brain (CMB) have recently published experimental evidence indicating that rats have the capacity to recollect, and that the capacity for recollection depends on the hippocampus.
The research team, which includes Norbert Fortin, a CAS psychology research associate in the Laboratory of Cognitive Neurobiology, Howard Eichenbaum, a CAS psychology professor and CMB director, and Sean Wright (UNI’03), a CAS psychology research technician, adapted a technique known as receiver operating characteristic (ROC) curves, which customarily is used to study memory in human beings, to study smell memory in rats.
Presented with an odor-memory task, the rats generated ROC curves similar to humans’ — a combination of asymmetrical and curvilinear components — which indicates that the rats use both recollective memory and recognition. In later testing of an experimental group of rats whose hippocampus had been removed, the recognition ROC curve remained, but the asymmetric result was lost, indicating that recollection was no longer functioning in those animals.
Although the researchers clearly state that their findings shed no light on the subjective experience of the animals, they do provide the first objective evidence of a distinction between these two types of memory in a nonhuman species.
This research was published in the September 9 issue of the journal Nature. Further information about research at the Center for Memory and Brain is available at http://www.bu.edu/cmb.
Babies and AEDs. Not all antiepileptic drugs (AEDs) are equally safe for pregnant women, according to a recent study by Diego Wyszynski, a MED research assistant professor of medicine, epidemiology, and biostatistics. Wyszynski is senior epidemiologist with the North American Antiepileptic Drug Pregnancy Registry.
At a recent meeting of the European Federation of Neurological Societies held in Paris, Wyszynski announced the results of two large studies comparing the risk of birth defects among the babies of women taking various AEDs. He found that women taking valproic acid, an AED used since the 1970s, had a risk of babies with birth defects between two and three and a half times greater than that of women taking newer medications.
The research was based on data from two pregnancy registries that have tracked women taking AEDs during pregnancy for the past 10 years. The data from a UK registry of 2,637 women in Britain revealed that the risk of serious birth defects is 2.9 and 2.3 percent for the babies of women taking lamotrigine and carbamazepine, respectively. These figures are within the range observed in the general population of women not taking any AED. However, the risk is substantially higher for women taking valproic acid: 6 percent. Data from a North American registry of 3,400 women showed a 2.9 percent risk for the newer drugs, compared to a 10.7 percent risk for valproic acid.
Approximately 25 million women worldwide have epilepsy; most have normal pregnancies and healthy children. However, since uncontrolled seizures pose significant health risks to both mother and child, physicians continue to prescribe AEDs during pregnancy. Approximately 50 percent of all women with epilepsy continue using the first AED prescribed to them, according to Wyszynski, so it is important that these women and their physicians be better informed about the comparative risks of the various medications as early as possible.
Further information about Wyszynski’s research can be found at http://genetics.bumc.bu.edu/people/faculty/wyszynski.htm. For more information on the North American Antiepileptic Drug Pregnancy Registry, go to http://aedpregnancyregistry.org/.
Briefs" is written by Joan Schwartz in the Office of the Provost. To read
more about BU research, visit http://www.bu.edu/research.