Smokers may have a reason to avoid kicking the habit if they wish to maintain their optimum level of memory and cognitive functioning.

A study published in the April 5 issue of the journal Neuron found that for those people who smoke regularly, nicotine can stimulate certain chemicals involved in higher cognition and memory function, said Huibert Mansvelder, associate professor of neuroscience and researcher at the University of Amsterdam.

He added it also stimulates memory and cognitive functioning for Alzheimer's and Parkinson's disease patients.

In the past 20 years, research has indicated that nicotine has an effect on learning, but until Mansvelder's study the exact cellular processes involved were unclear, he said "The question that came out of [previous research] was, although we know nicotine has an effect on people, we have no idea of [its] cellular effects," he said.

Researchers used memory tests to evaluate the effects of nicotine on higher cognition, Mansvelder said. Subjects who regularly smoke cigarettes performed worse on tests if they had not smoked just before taking the exam, he said.

Because of frequent exposure to nicotine, regular smokers have developed more receptor cells in the brain that are activated by chemicals like nicotine, Mansvelder said. Thus, when smokers have a cigarette, all of their receptor cells are activated and cognitive functioning is brought to their optimum levels, he said.

David Vandenbergh, associate professor of biobehavioral health, said the process of learning requires a change in the strength and frequency of brain cells firing -- a change that occurs when the brain is exposed to chemicals including nicotine. Students should not smoke cigarettes with hopes of doing better on exams in school, Vandenbergh said. "One cigarette is not going to measurably change your IQ," he said.

Patients with conditions such as Alzheimer's and Parkinson's lack acetylcholine -- a chemical that activates brain cells involved with higher cognition and long-term memory, he said. Although acetylcholine is not the same as nicotine, the chemicals' structures are similar enough that nicotine can bind to and stimulate acetylcholine receptors to increase activity in certain brain areas. "Nicotine can increase their attention behavior," he said.

Laura Klein, associate professor of biobehavioral health, said nicotine stimulates the area in the brain associated with rewards, arousal and learning. Dopamine, a chemical involved in attention and rewards, is the same chemical that is involved in addiction. Because learning and addiction work with similar cellular processes, Klein said addiction should be considered a "learning problem" rather than a problem with behavior.

Mansvelder said the findings of the research may be used to develop drug treatments for patients with psychiatric disorders, whose cognitive functioning could be brought to optimum levels by a treatment containing nicotine, he said. "I hope in the future pharmaceutical companies will be helped by the knowledge and understanding that our [research] provides," Mansvelder said.