Using optogenetics, a Swiss research team has at last proven the long-suspected link between cocaine use and physical brain change. The team also found a means to reverse such changes in the brains of newly addicted mice.1
Cocaine increases the firing potential of neurons in the nucleus accumbens (NAcc), the part of the brain that governs reward and pleasure. Monitoring mice that have been given several rounds of cocaine, the team expressed light-sensitive ion channels in cortical neurons that communicate with neurons in the NAcc. They then fired laser pulses to set off a “storm of chatter” between the two neuron types. This caused the neurons to reduce firing on their own, mitigating the effect of the cocaine. This method does not constitute a method for treating addiction since it appears only to work on the brains of mice that are newly addicted. Apparently, the brains of long-term addicts are changed in other less-understood ways after extended cocaine use. But the researchers hope next to find and undo other drug-induced brain changes in mice.
A method that combines genetics and light-based control of selected cells in living animals, optogenetics is a nascent, versatile application that holds has already had a significant impact on both biomedical research and treatment.
1. V. Pascoli, M. Turiault, and C. Lüscher, Nature, doi:10.1038/nature10709 (2011).