Between a glass of fruit juice now and a glass of champagne, what do you choose? Do you find it difficult to resist immediate pleasures or do you prefer to wait for an even greater joy? This dilemma, we are inevitably confronted with it on a daily basis. The Inserm team led by Mathias Pessiglione wanted to know why we sometimes give in to temptation.
Discovering the mechanisms involved can help us understand a lot of things that impact our health, for example why we eat too much fat and sugar when we are exposed to cholesterolor overweight or why we continue to smoke so much when we know perfectly long-term risks.
The French study, published in the journal Plos Biology, lifts the veil on these a priori irrational choices. In fact, they would find their origin in the dorso-lateral region of the prefrontal cortex. This region of the brain plays a role in controlling behavior.
Alzheimer’s disease leads to temptation
During several experiments, the researchers subjected an MRI of the brain to a set of volunteers. They had to choose between an immediate financial gain, 10 euros for example, or a greater gain later (11 euros tomorrow). Some choices seemed more difficult to make because they appealed to the imagination. It was a question of choosing an immediate gift visible on a photo or a more interesting gift but in a more distant future and more difficult to imagine.
The same tests were done on patients with Alzheimer’s.
It became clear that the choice of future rewards is associated with the activity of the prefrontal cortex. Alzheimer’s patients preferred immediate satisfaction, since their deficient memory makes them incapable of imagining future pleasures. “This is because the hippocampus is needed to imagine future situations with a wealth of detail that makes them appealing enough,” says Dr. Pessiglione.
