Posted on 24 October 2017
Scientists, including Dr Deniz Vatansever from the University of York’s Department of Psychology, have shown that far from being just ‘background activity’, the so-called ‘default mode network’ may be essential to helping us perform routine tasks.
When we are performing tasks, specific regions of the brain become more active – for example, if we are moving, the motor cortex is engaged, while if we are looking at a picture, the visual cortex will be active. But what happens when we are apparently doing nothing?
In 2001, scientists at the Washington University School of Medicine found that a collection of brain regions appeared to be more active during such states of rest. This network was named the ‘default mode network’ (DMN). While it has since been linked to, among other things, daydreaming, thinking about the past, planning for the future, and creativity, its precise function is unclear.
Abnormal activity in the DMN has been linked to an array of disorders including Alzheimer’s disease, schizophrenia, attention-deficit/hyperactivity disorder (ADHD) and disorders of consciousness. However, scientists have been unable to show a definitive role in human cognition.
Now, in research published in the Proceedings of the National Academy of Sciences (PNAS), scientists have shown that the DMN plays an important role in allowing us to switch to ‘autopilot’ once we are familiar with a task.
Dr Vatansever said: “Rather than waiting passively for things to happen to us, we are constantly trying to predict the environment around us.
“Our evidence suggests it is the default mode network that enables us do this. It is essentially like an autopilot that helps us make fast decisions when we know what the rules of the environment are. So for example, when you’re driving to work in the morning along a familiar route, the default mode network will be active, enabling us to perform our task without having to invest lots of time and energy into every decision.”
Dr Vatansever carried out the study as part of his PhD at the University of Cambridge, before joining York as a Research Associate last year.
Senior author Dr Emmanuel Stamatakis from the Division of Anaesthesia at the University of Cambridge, said: “The old way of interpreting what’s happening in these tasks was that because we know the rules, we can daydream about what we’re going to have for dinner later and the DMN kicks in. In fact, we showed that the DMN is not a bystander in these tasks: it plays an integral role in helping us perform them.”
This new study supports an idea expounded upon by Daniel Kahneman, Nobel Memorial Prize in Economics laureate 2002, in his book Thinking, Fast and Slow, that there are two systems that help us make decisions: a rational system that helps us reach calculated decisions, and a fast system that allows us to make intuitive decisions – the new research suggests this latter system may be linked with the DMN.
The researchers believe their findings have relevance to brain injury, particularly following traumatic brain injury, where problems with memory and impulsivity can substantially compromise social reintegration. They say the findings may also have relevance for mental health disorders, such as addiction, depression and obsessive compulsive disorder, where particular thought patterns drive repeated behaviours, and the mechanisms of anaesthetic agents and other drugs on the brain.
The research was supported by the Yousef Jameel Academic Program, The Stephen Erskine Fellowship from Queens’ College Cambridge, and the NIHR Cambridge Biomedical Resource Centre.
His study of the default mode network, published in Proceedings of the National Academy of Sciences (PNAS), was carried out as part of his PhD at the University of Cambridge. He is now working on neural representations of mind-wandering (daydreaming) with Dr Jonathan Smallwood at York.