If you give a mouse a cookie, it’s going to ask for a glass of milk. If you give a mouse cocaine, its children may experience short-term memory loss, according to a paper by three Yale researchers.

Their research demonstrates that prenatal cocaine exposure in rats disrupts the activity in certain areas of the brain related to short-term memory. The investigation, published earlier this year, is part of a series of studies conducted by Bret Morrow, John Elsworth and Robert Roth, members of the psychiatry and pharmacology faculties who have been surveying both the anatomical and behavioral effects of cocaine exposure in young rats.

The team exposed pregnant rats to the substance and then monitored the behavior and cerebral activity of their offspring.

In one part of the study, researchers gave both cocaine-exposed and normal rodents objects to explore, removed the objects and replaced them a short time later. They then measured the amount of time each animal spent reexamining the objects, assuming that the longer the animal spent, the less familiar it was with the item.

“We noted that [the cocaine-exposed rats] did have short-term memory deficits that were different than regular rats,” Morrow said.

The researchers then examined the areas of the brain associated with short-term memory and attention, particularly the medial prefrontal cortex. Morrow said this region was significantly more active in the affected rats than in the control animals.

“They have a hyper-activated prefrontal cortex, and it seems to be due to a loss of inhibitory function,” he said. “Basically, they can’t turn off that part of their brain.”

In their most recent report, the scientists announced that changes on the cellular level occur within the brains of cocaine-exposed rats, limiting the production of inhibitory structures. This means that there are actual anatomical differences between the brains of drug-exposed and normal animals, Morrow said.

The team’s research came about in response to an increase in the number of children exposed to cocaine in the womb after the drug’s usage surged in the United States in the 1990s, Morrow said.

According to the National Institute on Drug Abuse, up to 1 million children born in the United States since the mid-1980s have been exposed to cocaine prenatally.

Children who are affected by prenatal cocaine exposure exhibit symptoms similar to those of attention deficit disorder, Morrow said, and they can experience attention-related difficulties in school.

But he said it is sometimes difficult to pinpoint the effects of prenatal cocaine exposure in child subjects because their mothers’ substance abuse problems are usually not limited to one drug.

“One of the problems is that there are not a lot of kids that you can look at and are prenatally exposed that have just one problem,” Morrow said.

Bernetta Witcher-Boateng, the program director for Amethyst House Crossroads, a substance abuse treatment center in New Haven, said most, if not all, of the women at the facility who smoked crack cocaine when pregnant also abused alcohol.

However, studies conducted in the last few years have attempted to isolate and examine the effects of prenatal cocaine exposure.

Dr. Lynn Singer and her team of researchers at Case Western University in Cleveland, conducted some of the few studies examining the development of cocaine-exposed infants over time.

“There is actually quite a line of findings … [in which] we have identified attention difficulties in cocaine exposed children,” she said.

Singer said visual attention difficulties have been identified in children as young as one month old, and language reception difficulties have also been linked to cocaine exposure.

Maternal cocaine abuse is primarily a problem within low-income areas and is present in New Haven, Boateng said.

Of the approximately 45 women admitted to the Amethyst House each year, 90 percent are crack cocaine addicts and used the drug while they were pregnant, she said.

The center has a rehabilitation program for children exposed to cocaine before birth.

“For the children, because they are exposed to drugs, we have a therapeutic nursery,” she said. “They work on social, emotional and physical development.”

Many of the women who have left the Amethyst House report that their children need further therapy and experience problems in school, Boateng said.

Morrow said the Yale research team hopes its results will pave the way for new and more effective treatments for prenatal cocaine exposure in children.

Further progress on the anatomical level may make these objectives possible, Singer said.

“Obviously if you can understand the chemical structure, it paves the way for developing medications that can potentially make a difference,” she said.