We’ve all been there. Whether it’s at a crucial moment of an exam, walking into a room for a specific purpose, or making an impromptu speech, your mind goes blank.

It can be frustrating, stressful or worrying.

But what’s really going on in your brain? And when should you go to your GP for a check-up?

What is mind blanking?

One of the earliest observations in psychology is that our thoughts usually produce a stream of consciousness, flowing almost constantly.

Often our attention and thoughts are focused. Other times, our mind wanders.

But less often (perhaps about 15% of the time) our mind goes completely blank. So in recent years, researchers have begun trying to find out why.

Mind blanking can happen when we intend to retrieve a memory, and find it gone. This could be completely forgetting the answers to questions in an exam, or forgetting why we walked into a room.

It can also happen when we are not aware of thinking at all. Someone might ask us a question, and we realise we had “zoned out”.

Sometimes this zoning out is due to our mind wandering, and we are aware of our thoughts. However, at other times, when we’re not sure where our mind went, this is mind blanking.

Some people are much more likely than others to say their mind goes blank. These include people with ADHD (attention deficit hyperactivity disorder) or anxiety.

Mind blanking is also more common in certain kinds of dementia, such as Lewy body dementia, and in people who are sleep deprived, or after intense physical exercise.

Let’s start with the brain

To understand what causes our mind to go blank, we need to start with how our brain usually pays attention and learns new memories.

A key brain network involved in these processes is the executive attention network. This is a network of interconnected brain regions that’s important for being alert, paying attention and feeling motivated.

These brain areas are connected to regions in the outer layer of the brain, the frontal and parietal cortex, which support our planning, decision-making and sensory integration.

This executive attention network is used both for passing information to our memory systems for storage, and then later retrieving those memories when we need them.

One of the key brain chemicals that supports this network is noradrenaline, also known as norepinephrine. This controls our alertness and readiness for action.

So what happens when our mind goes blank?

Disruption in any part of the executive attention network can impact the brain’s ability to pay attention and retrieve memories, leading to a blank mind.

When we’re sleep-deprived

Fatigue caused by sleep deprivation or sleep disorders can impact the alerting part of the network.

When we are very tired, we can experience “local sleep”. This is where the activity in parts of our brains is sleep-like even if we are awake. This can cause the attention system to temporarily shut off, which researchers think may lead to mind blanks.

Neuroimaging research shows parts of the executive attention network are “deactivated” during mind blanking.

This likely explains what causes the “zoning out” kind of mind blank.

When we’re stressed

High levels of stress or anxiety, such as what we might experience in an exam room, can result in high levels of noradrenaline. This puts the body in “fight or flight mode”.

This focuses our attention on immediate threats, reducing its ability to retrieve what it sees as non-essential memories, such as information you’ve been revising the day before.

When we’re multi-tasking

If the executive attention network doesn’t encode a memory efficiently in the first place – because for example, we were multi-tasking or distracted – then it might not be easily retrieved later on. This can also lead to a mind blank.

When is it time to see your GP?

While mind blanking is common and usually no cause for concern, frequent mind blanking can be a sign of a medical condition.

Some conditions that affect these attention network systems, include depression, anxiety, dementia or stroke. A condition that affects the memory systems themselves, such as Alzheimer’s disease, can also look like mind blanking, as can some kinds of seizures.

So, generally speaking, if you’ve noticed mind blanking becoming more common, if there has been a sudden onset of symptoms, or if your friends or family have raised concerns, see your GP for a check-up.

If you’ve noticed any changes to your ability to undertake your daily activities, or you find yourself confused or disorientated, you should also see your GP.

If you go to your GP for a check-up, they may take a medical history, and ask you some questions to assess your thinking and memory skills.

They may also refer you for neuropsychological or neurological assessment, or request a brain scan (like a CT or MRI scan) to check for any brain changes caused by stroke or dementia.

Sophie Andrews, Associate Professor and Lead, Healthy Brain Ageing Research Program, Thompson Institute, University of the Sunshine Coast

This article is republished from The Conversation under a Creative Commons license. Read the original article.