Nanogirl Michelle Dickinson: Let me jog your memory

Researchers are testing the biology of memory.

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Forgotten something? We all forget things from time to time, but new research suggests that the simple act of waiting until later in the day could be all it takes to jog our memory.

While scientists know that memories are formed through connections between neurons, the way in which are brains retrieve memories is still poorly understood. With over 100 billion neurons in our brain, it is thought that each individual memory we make comes from tweaking a tiny subset of one or a few of these neurons changing the way they communicate.

While we might believe that we remember things incredibly clearly, our own memories are a highly personal reconstructive process. Rather than remember an exact replica of the things we originally experienced, each of our memories are actually biased by our personal knowledge and experience resulting in the memory of an event being unique and individual to us alone.

Understanding how memories are made is complicated enough however, the biology behind how we forget things is even more complicated. This is because trying to distinguish between what we don't know and what we don't remember is a challenging task.

This week, new research published in the journal Nature communications attempted to measure forgetfulness using a simple mouse experiment. Young adult mice were put through a simple training program in which they went through a learning phase where the mice explored a new object for a few minutes before it was taken away from them.

To test if the mice remembered the object at a later date, they were put through a recall phase where the same object was re-introduced and the amount of time the mice spent touching the object was recorded.

As mice spend less time touching objects that they remember, it was easy for the researchers to determine using time whether or not the mice remembered something they had seen before.

After testing the mice at different times from right before they were due to wake up to right before they were due to go to sleep, they found that the ability of the mice to remember the object was related to the time of day.

Mice that were re-shown the object just before they would normally wake up were much less likely to remember having seen the object than mice that were re-shown the object right before going to sleep. The scientists believed that this was related to a protein called BMAL1 which regulates the expression of many other genes.

BMAL1 is normally low right before animals wake up and high before going to sleep. To test this theory further, the researchers repeated the test using mice that were bred not to produce any BMAL1 at all and as predicted these mice were even more forgetful especially when tested right before they would normally wake up.

The experiments showed that, at least in mice - memory retrieval performance is dependent on the time of day with just before they normally wake up as the peak time for forgetfulness. This agrees with previous research showing that the body's circadian clock affects learning and memory formation.

Understanding how BMAL1 is related to memory could help scientists researching memory deficit diseases like dementia and Alzheimer's.

For those of us who can't change our own biology, it's worth knowing that the strength of a memory, just like a muscle can be trained over time. By actively practicing recalling the memory again and again you are more likely to remember it later on.

So if you do find yourself forgetting things – don't panic, just try again later on in the day – it could just be biology working against you.