AN INTRODUCTION TO HOW THE BRAIN STORES MEMORIES — AND PRACTICAL WAYS YOU CAN BOOST YOURS.
YOU’RE RUNNING LATE and, for the life of you, you can’t remember where you put your keys. Ah, memory... it can be so befuddling — occasionally working marvellously well, but often giving you the slip.
Don’t fret: it’s not just you. The way human memory works is so complicated that scientists are still trying to figure it out. What we do know is that nerve cells communicating with each other in the presence of neurotransmitters (aka the chemicals that facilitate the transmission of neural signals) to process information in the brain, and the strength of these signals, is what is believed to be behind the formation of memories. “The persistent strengthening of these activated synapses (connections) between neurons is called long-term potentiation (LTP),” explains William Griffith, a cellular neuroscientist at the Texas A&M Health Science Center College of Medicine. “LTP is the most recognised cellular mechanism to explain memory because it can alter the strength between brain cell connections. If this strength is maintained, a memory can be formed.”
Memory is composed of sensory cues like sight and smell, meaning different parts of the brain need to be firing at the same time to summon memories of any type, from your nana’s homecooked meals, to how to ride a bicycle. Moreover, sensations only become memories if they’re ‘encoded’ into the brain, which is achieved using chemicals and electrical impulses. For that, you’ll need to have been paying attention to something. If you aren’t, chances are the event won’t be encoded, and you therefore won’t have any associated memories.
Your initial sensory perceptions of an event get stored as short-term memory. These perceptions can be visual, tactile, aural or olfactory (ie smell). Memories can even be a combination of these. Short-term memories have an expiry date, but recall them a few times and they become part of your long-term memory. The more you recall something, the stronger the synaptic connections, the stronger and longer the memory.
There’s no such thing as ‘good’ or ‘bad’ memory. We all deem different things to be important, so our memories are just as selective and varied as our personalities. If you’ve forgotten where you left your keys, you either weren’t paying attention to where you left them or, when searching for them, there are too many distractions around you, hampering the recall power of the memory. Moreover, if one or more synaptic connections didn’t fire at the time of recollection, it is possible that those connections can get made later, giving you the proverbial light-bulb moment when you remember where you left your keys long after you’ve stopped looking.
MEMORY AND AGING
After the age of 20, our brains begin to experience the occasional breakdown of the memory recall processes. This is absolutely normal, and increases in frequency as we get older, as ageing causes the strength in the brain’s nerve synapses to falter, affecting our ability to remember things. In fact, some areas of our brain that are important to memory recall become vulnerable as we get older, like the hippocampus, which loses 5% of its cells for every decade we age. So not being able to remember a person’s name at a social event is quite normal, and may not necessarily be a sign of dementia.
Like any other organ in the body, the brain undergoes wear-and-tear as we get older, and without proper ‘exercise’, the brain also suffers. As we mentioned in a previous Get Psyched column (see issue 67, page 19), creative and intellectual pastimes (like reading and crossword puzzles) keep the brain firing and, according to a study published in the journal ‘Neurology’ in 2013, can help to reduce the risk of late-life cognitive degeneration by up to 32%.
Along with these kinds of ‘brain workouts’, a healthy lifestyle also goes a long way in keeping the brain ticking. Eating the right foods (like the Mediterranean diet, which is known to contain memory-boosting foods), plenty of physical exercise and keeping regular sleep patterns have also been known to have positive effects, as does keeping your brain hydrated by making sure you drink enough water.
Social interactions are known to ward off depression and other stress factors which can affect memory recall. So get out there and be social — and we don’t mean via Facebook!