Two researchers share their reasons for researching transcranial magnetic stimulation (TMS) for treating cocaine addiction, and describe challenges to moving forward this potentially promising therapy.
In mice, a cocaine-induced imbalance in the activity of two key populations of neurons in the reward system persists for a longer period after repeated exposure to the drug. For long-term users, this change could both weaken the cocaine “high” and strengthen the compulsion to seek the drug.
Adolescent monkeys that were exposed to THC fell progressively further behind THC-free monkeys in their ability to recall the location of an object after a brief delay.
This animation shows the rapid passage of cocaine through the brain. It demonstrates that the intensity of the cocaine “high” parallels the trajectory of cocaine levels in the brain.
The Scientific Director of NIDA’s Intramural Research Program talks about switching off animals’ compulsive cocaine seeking by optogenetically activating the prefrontal cortex, and the implications of this work for people. In an accompanying podcast, Dr. Bonci walks viewers through experiments that showed that prefrontal cortex activity levels may constitute a simple switch controlling whether or not animals compulsively seek cocaine.
Methamphetamine alters brain structures involved in decision-making and impairs the ability to suppress habitual behaviors that have become useless or counterproductive. The two effects were correlated, indicating that the structural change underlies the decline in mental flexibility.
Researchers have shut down laboratory rats’ compulsive cocaine seeking by stimulating an area of the animals’ prefrontal cortex. The finding raises the possibility that stimulating neurons in this brain area may weaken or break cocaine’s grip on the behavior of people who are addicted to the drug.
New research demonstrated that, in rhesus monkeys, ongoing cocaine exposure weakens two brain functions that people require for successful behavioral change: cognitive flexibility and memory. But the study determined that these changes may not be permanent.
While viewing images of cigarettes, smokers reported milder cravings when they shifted their focus from the pleasures of smoking to its harmful effects. Brain imaging showed a correlation between the reductions in craving and altered activity levels in regions associated with emotional regulation and reward.
