“Compared to saline injections, nicotine strengthens nerve connections — sometimes up to 200 percent. This strengthening of connections underlies the formation of a new memory.”
Most smokers or ex-smokers will tell you that the urge to smoke is stronger when one drinks. Sometimes an ex-smoker will not miss smoking at all, but the moment he touches an alcoholic drink, all he craves is a cigarette. Researchers at Baylor College of Medicine say the culprit is nicotine, which “tricks” the brain into creating memory associations between environmental cues and smoking behavior. The results of this research appeared in the journal Neuron.
Our brains usually create these associations between the things that underpin our existence and the environmental cues in order to manage behaviors that lead to successful lives. Danny, a professor of neuroscience at BCM and co-author of the study, “The brain sends a reward signal when we behave in a way that contributes to our well-being.” “However, nicotine drives this unconscious learning process in the brain so we start to act as if smoking is a positive action.”
Danny explained that in the future, smoking-related events can become signals that lead one to smoke. These signals are all familiar to former or current smokers and can include finishing a meal, a drink, and even driving a car. To analyze these associations, Danny and his team decided to record the rats’ brain activity while they were exposed to nicotine, by letting them walk around in a space with two separate sections, one containing nicotine and the other on benign saline.
The researchers recorded how long the mice spent in each compartment, while recording activity in the hippocampus, an area of the brain associated with creating memories. “The change in brain activity was amazing,” Danny said. “Compared to saline injections, nicotine strengthens nerve connections — sometimes up to 200 percent. This strengthening of connections underlies the formation of a new memory.”
Nicotine strengthens memory, forming nerve connections
Unsurprisingly, the mice learned to spend more time in the nicotine chamber. “We found that nicotine can only strengthen synaptic connections when so-called reward centers send a dopamine signal. This was a critical process in forming memory connections even with bad behavior such as smoking.”
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