Lights! Neurons! Action! Binge-drinking lab rats go cold turkey
A new study using light to target and stimulate specific neurons in lab rats trained to drink much the way human binge-drinkers do finds the rodents "flat out stopped drinking."
Forget rehab, medication, and counseling. What if light could one day help cure us of our addictions?
Reporting in the journal Frontiers in Neuroscience, researchers at the University of Buffalo and Wake Forest University shed light on a different way to go about deep brain stimulation that may have profound and lasting effects -- at least when it comes to binge drinking in lab rats.
Instead of using electricity to blast neurons indiscriminately, the researchers turned to an emerging technique known as optogenetics, using light to target and stimulate specific neurons (in this case dopamine).
And it worked. Very convincingly.
"The rats just flat out stopped drinking," first author Caroline Bass, a University at Buffalo assistant professor of pharmacology and toxicology, said in a news release. "By stimulating certain dopamine neurons in a precise pattern, resulting in low but prolonged levels of dopamine release, we could prevent the rats from binging."
What's more, the rats, who had been trained to drink much in the way that human binge-drinkers do, stopped drinking altogether after the stimulation, avoiding the available alcohol.
"For decades, we have observed that particular brain regions light up or become more active in an alcoholic when he or she drinks or looks at pictures of people drinking, for example," Bass added, "but we didn't know if those changes in brain activity actually governed the alcoholic's behavior."
By demonstrating a causal effect, the researchers say they now better understand the neurochemical basis of drug addiction and are hopeful that the approach could not only extend to humans but have implications beyond alcoholism, helping inform treatments for a wide range of addictions and neurological illnesses.
Because our brains house many different types of neurons, which in turn have various neurotransmitters and functions, the team used optogenetics so that they could target one type of neuron in particular: dopamine. Bass created a virus that would introduce a gene encoding a protein that is responsive to light -- but only when in dopaminergic neurons. This enabled her team to target and then activate one type of dopamine neuron in the brain's reward system.
In doing so, they were able to see that the neuronal pathways affected by binge drinking are the ones known to play a role in a range of neurological disorders, which is why they are hopeful that this approach could also prove useful in people with Parkinson's, schizophrenia, depression, addiction, and beyond. And by targeting genes to specific dopamine neurons, it's possible that gene therapy in the brain could someday play a role in treatment as well.
The research was funded by the National Institutes of Health and is in step with the goals of BRAIN, President Obama's Brain Research for Advancing Innovative Neurotechnologies initiative.