CAMBRIDGE, United Kingdom — The discovery of a part of the brain which links actions to outcomes may lead to a treatment to addiction and obsessive compulsive disorder. Researchers from the University of Cambridge say the brain region, called the anterior cingulate cortex, could become a target of therapies which break addiction and help with behavioral disorders.
Impairing the brain’s ability to associate actions with outcomes has a link to compulsive behaviors among people with OCD and those who suffer from severe addiction issues. The new study finds the worrying or obsessive behaviors these people display, like seeking out drugs, may be because patients have their wires crossed and are not correctly associating actions and outcomes.
Previous studies have discovered that part of the brain’s prefrontal cortex plays an important role in applying goal-orientated behaviors. However, the prefrontal cortex is a complex structure with many regions, and so it has not been possible to pinpoint what part is behind these counter-intuitive behaviors.
Now, scientists have discovered exactly what part of the brain determines whether people change their behavior or simply continue doing what they have always done.
“We have identified the very specific region of the brain involved in goal-directed behavior,” Dr. Lisa Duan says in a university release. “When we temporarily turned this off, behavior became more habitual – like when we go onto autopilot.”
Monkey business reveals link between actions and outcomes
To identify what areas of the brain are involved in goal-orientated decision making, the researchers carried out an experiment involving a species of monkeys called marmosets. Researchers chose these animals because their brains share certain similarities with humans. The different regions of their brain can also be manipulated in similar ways.
The team taught the marmosets a goal-orientated behavior, using a colored cross appearing on a touchscreen. If they tapped it, the marmosets were rewarded with their favorite juice to drink. The animals were then given the reward without having to respond, breaking the mental connection between the juice and the image.
Researchers say the marmosets quickly realized they would be rewarded regardless and stopped responding to the image. They were then given drugs which temporarily switched off their anterior cingulate cortex and its ability to communicate with another brain region, called the caudate nucleus.
Repeating the experiment, the drugged animals continued to tap the cross even after seeing they would be rewarded regardless of their actions. When other parts of the brain, also playing a role in decision making, were switched off the animals did not continue behaving this way.
Addiction treatments on the horizon?
Study authors say this shows the caudate nucleus region is specifically responsible for goal-orientated behaviors. Researchers observed a similar effect among patients with Obsessive Compulsive Disorder (OCD) or addiction. When the relationship between an action and an outcome is uncoupled, the patients continue to behave in the same way.
“We think this is the first study to have established the specific brain circuitry that controls goal-directed behavior in primates, whose brains are very similar to human brains,” says co-author Professor Angela Roberts.
“This is a first step towards identifying suitable molecular targets for future drug treatments, or other forms of therapy, for devastating mental health disorders such as OCD and addiction,” adds Professor Trevor Robbins.
The findings appear in the journal Neuron.
SWNS writer Tom Campbell contributed to this report.