How stress blocks working memory


If you have ever had to perform under stress, whether it be sitting an exam, auditioning for a play or presenting in a meeting, you may recognise that despite “knowing” your stuff, your actual performance may not always match up to expectations. This is likely to be exacerbated if during that time you are distracted by a noise or interruption.

 

But more than that, stress is thought to account for half of all work place related accidents and contributes significantly to the escalating incidence of mental illness in our society.

 

Stress has an effect on the part of our brain, the pre frontal cortex, which is also known as our “executive suite”. This part of our brain is vital for us to be able to pay attention, plan, organise, regulate our emotion and is the place where we have our working memory, where neurons hold information for short periods of time. Our working memory has been likened to a whiteboard in class used to write up information. Once that information has been discussed or learnt, the whiteboard can be wiped clean ready for the teacher to write up something different.

 

It has been thought that the effect of stress on our executive suite, simply suppressed brain cell activity. However, new research indicates that the way stress actually affect our brain is that it modifies how the neurons are working.

 

It turns out that our clever neurons, which communicate with each other every thousandth of a second (even Usain Bolt can’t match that pace) fire and refire to keep the stored information fresh. A neuron can “remember” what it did one to one and a half seconds ago, but if it don’t self stimulate itself again, that information is then lost.

 

So in the presence of stress, our neurons simply get distracted from this repeated self stimulation, and the information gets lost as the neurons react to other stimuli such as white noise or whatever else the stress distraction might be. It appears that distractions, (the bane for many of us) have an effect right down to the level of an individual neuron.

 

In rat studies where the animals had to find a reward (a chocolate chip) in a maze, when unstressed they achieved a 90% success rate because their brains stored the memories for long enough for them to remember the correct route. However in the presence of white noise causing stress, this success rate was reduced down to 65%.

 

Humans have been shown to exhibit similar stress patterns to white noise as rats. So for people working in areas where they may be exposed to high stress or distractions (does that include the vast majority of the working population?) their ability to perform well or accurately is significantly impaired.

 

Working in an office with distractions is one thing, but what about people working in environments where your ability to stay focussed and on track is more critical, such as air traffic controllers, military personnel and neurosurgeons?

 

More than ever, our ability to recognise and manage our distractions is being recognised as being crucial to our ability to work well. How do you manage your distractions and stress at work?

 

Ref:

Devilbiss DM, Jenison RL, Berridge CW. Stress-Induced Impairment of a Working Memory Task: Role of Spiking Rate and Spiking History Predicted Discharge. PLoS Computational Biology, 2012; 8 (9): e1002681 DOI: 10.1371/journal.pcbi.1002681

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