Recently a study conducted by researchers on freely moving mice showed how the use of addictive drugs influence the neural processes associated with learning and memory.
The use of drugs, as is known to all, affects the level of dopamine secretion in the brain and this neurochemical has a pivotal role to play in the brain’s reward system. Dopamine also takes part in the neural processes involved in learning by strengthening the neural connections known as synaptic potentiation. Research evidence has also pointed out that the hippocampus, a brain structure involved in formation of new memories, is also responsible for development of drug addiction.
Physiologically relevant quantity of nicotine, the addictive component of tobacco was applied to freely moving mice and the corresponding changes in the brain were recorded by the researchers. It was noted that nicotine induced synaptic potentiation correlated with the mice learning to prefer a place associated with nicotine use. But these effects require a local dopamine signal within the hippocampus.
“Although addictive drugs like nicotine have been shown to influence the induction of synaptic potentiation, there has been little or no research in freely moving animals that monitors ongoing induction of synaptic potentiation by a biologically relevant drug dose,” explains senior author Dr. John Dani from the Department of Neuroscience at the Baylor College of Medicine in Houston, Texas.
“An animal’s memories or feelings about the environment are updated when the dopamine signal labels a particular event as important, new, and salient. Normally these memories help us to perform successful behaviors, but in our study, those memories were linked to the addictive drug.
When specific environmental events occur, such as the place or people associated with drug use, they are capable of cuing drug-associated memories or feelings that motivate continued drug use or relapse,” concluded Dani.
The study has been published in the journal “Neuron.”