The Neurobiology of Drug addiction
What happens in the brain that turns normal motivation into an addiction? Addiction is believed to be underlied by alterations of specific synapses in the reward system. These alterations may cause the incontrollable desire to consume the drug. Which synapses are altered during the development of addiction? What exactly are the changes? Can we attenuate addictive behavior by compensating for the synaptic alterations caused by drugs? A main goal in our lab is to reveal the permanent synaptic changes that occur in drug addiction in specific neurons of the reward system. We then aim to target the altered synapses with the intention to attenuate addictive behavior. To achieve this we use animal models of drug addiction together with electrophysiological and optogenetic/chemogenetic tools in transgenic mice.
The glutamatergic input to the nucleus accumbens, measured as AMPA/NMDA, is permanently potentiated after extinction of cocaine use and even further potentiated after reinstatement. The level of potentiation is strongly correlated with the motivation to obtain cocaine during the reinstatement session.
(Adapted from Gipson*, Kupchik*, Shen* et al. 2013 Neuron)