Scientists identify part of brain that makes us 'think twice'
Neuroscientists at University College London in the UK and Ghent University in Belgium have found the brain circuit involved in thinking twice and controlling impulsive behaviour. Writing in the Journal of Neuroscience, the neuroscientists describe their discovery of an area in the fronto-median cortex of the brain that is activated when humans begin to think 'I am not going to go through with this' and stop themselves from doing what they were about to do. According to the authors of the study, this specific brain network is involved in self-control and controls and limits the desired actions of human beings. This is important in everyday life, where decisions to act or not in a given situation can have irremediable consequences. 'Many people recognise the 'little voice inside the head' that stops you from doing something, like pressing the send button on an angry e-mail,' says Professor Patrick Haggard from the UCL Institute of Neuroscience. 'Quite often we have an immediate desire to perform an action, but reflecting on the wider consequences could, and sometimes should, make us cancel the action. Our study identifies the brain processes involved in that last-minute rethink about what we're doing. These brain functions are important for human society in general: the ability to withhold an action prevents us all from being egoists, driven by our immediate desires.' In the past, similar studies have looked at a person's ability to cancel a prepared action in response to an external signal, like a stop sign for example. In this study, however, participants prepared for an action themselves, but then decided whether to go through with the action, or whether to withhold at the last minute. This allowed the scientists to identify the brain basis of 'self-initiated inhibition of action'. The team then monitored the brain activity in the fronto-median cortex using functional magnetic resonance imaging (fMRI) technology, while volunteers made up their minds when to push a button. The scientists discovered a small area in the anterior fronto-median cortex of the brain was active only when people restrained from an action that they had previously prepared. When people prepared and actually went through with the action, this area was considerably less active. 'We wanted to identify the brain areas that show more activity when people prepare an action and then inhibit it, than when they prepare the same action and then actually make it,' explains Dr Marcel Brass from Ghent University. The researchers were even able to predict how often individual volunteers inhibited actions from the brain activity in the fronto-median cortex. Those with strong activity in this area withheld actions frequently, while those with weak activity pressed the button more frequently, despite the instruction to sometimes withhold action. 'This could be a factor in why some individuals are impulsive, while others are reluctant to act,' believes Professor Haggard. 'Developments in brain imaging are bringing us ever closer to a scientific understanding of why a particular individual is the way they are. The ability to check, reconsider and withhold an action is essential given the complex social settings in which we live,' he concluded.
Countries
Belgium, United Kingdom