It is called avolition (or abulia) and is the almost total inability to make decisions or initiatives: it is a common symptom in disorders such as depression, schizophrenia and Parkinson’s, and makes it impossible for those affected to carry out even the most banal activities (such as making a telephone call) if considered unpleasant.
Until now it was not clear how the brain transformed poor motivation into a real block on action; now a study published on Current Biology has identified two brain areas which, by communicating with each other, slow down decisions.
The experiment. To understand how this internal brake works, the researchers worked with macaque monkeys, training them to perform two versions of the same task. In one, execution simply guaranteed a reward; in the other, an annoying puff of air on the muzzle was added to the reward.
The result was predictable: when they only had to carry out the task the macaques acted immediately, while faced with the discomfort of the breath of air they hesitated or gave up completely, even if the reward remained the same.
Motivational brake. The scientists then momentarily weakened a specific brain connection that unites two areas of the brain involved in motivation, the ventral striatum and the ventral pallidum. After this modification, the macaques asked to decide whether to face the task accompanied by the annoying puff of air were much more likely to throw yourself.
The results suggest that the circuit that connects the two brain areas acts as a real motivational brake, inhibiting our internal “start button” especially when an action is perceived as stressful or unpleasant.
Release the brake, but not too much. In light of what they discovered, the authors hypothesize that, in the future, it will be possible to intervene on this mechanism with tools such as deep or non-invasive brain stimulation, or with new pharmacological therapies, to regulate the motivational brake in people suffering from abulia.
Be careful, however: «excessively weakening this motivational brake could lead to dangerous behavior or an excessive propensity for risk», warns Ken-ichi Amemori, coordinator of the study. For this reason, he underlines, rigorous scientific validation and careful ethical reflection will be essential to understand when and how it is appropriate to intervene.
