In previous articles on this blog I’ve described some of the many long-term brain benefits of regular exercise. These have mainly focused on the benefits that regular exercise offers to older people in terms of reducing the rate of age-related cognitive decline. But the brain benefits of taking regular exercise are applicable to everyone, young and old.
Do It For Your Brain’s Sake
People who exercise regularly have lower rates of anxiety and depression. They even boast greater cortical thickness in parts of the prefrontal cortex and the medial temporal lobe. Specifically brain scanning studies have demonstrated that the left and right hippocampus, fundamental both to creating memories and knowing where we are in space, are a little larger than in sedentary people. This increase in tissue thickness is thought to be indicative of a denser meshwork of synaptic connections reflecting a greater complexity of neuronal network. In other words several brain areas fundamentally involved in memory and cognition are able to perform better. What’s more regular exercise leads to improvements in mood and even helps you sleep better. And there is little better than a good night’s sleep for helping brains to reach peak performance.
Exercise leads to increased levels of nerve growth factors like BDNF (brain-derived neurotrophic factors) that promote the birth and survival of new brain cells, synapses and development of new blood vessels. So this is thought to a likely mechanism for the changes in the thickness of various brain regions in people who take regular exercise and quite possible the long term benefits in cognitive ability and mental health.
In my talks, workshops and first book (Sort Your Brain Out) I urge people to move away from thinking about exercise as a pastime motivated by the desire to improve the appearance of our bodies and more as something we should get in the habit of doing regular exercise to manage our mood / productivity in the short term and brain health in the long term. When people are feeling stressed out their motivation to hit the gym is often at rock bottom levels. A huge shame because exercise is exactly what would make them feel much, much better almost immediately.
Athletes often talk of the “runner’s high.” This has long been explained as a result of endorphins released in the brain in response to moderate to intense exercise. It makes good theoretical sense because endorphins, the brain’s natural opiates, have the twin effect of numbing pain and making us feel good. The trouble is that up until 2008 there was little if any hard evidence to back this notion up. Yet further doubt was cast on the whole endorphin hypothesis when a study demonstrated that the runner’s high still occurred even when the effect of any released endorphins was blocked with a drug called naxalone.
Looking elsewhere for a mechanism through which the runner’s high might be achieved researchers started to focus on a possible role for endocannabinoids. Similar in structure to the hundreds of cannabinoid chemicals found in the Cannabis sativa plant smoked recreationally in pursuit of a mood-enhancing effect, endocannabinoids are naturally produced throughout the brain.
Subsequently, elevated endorphin levels were observed in a brain scanning study that compared brains that had recently completed a 2-hour endurance run compared to other brains that hadn’t (Boecker et al, 2008). So consensus now is that the anxiolytic effects of exercise are mediated by a combination of endocannabinoid and endorphin release in the brain.
From an evolutionary perspective pain signals clearly should be switch on and off-able because they can be helpful or disabling depending on the context. Pain signals from damaged body parts helps us to avoid worsening the injury when at rest or engaging in gentle exercise, clearly an advantage when the priority is to allow a twisted ankle, strained knee or inflamed muscle to heal properly. But in the context of evading a predator or attempting to catch prey, such pain signals could lead to the huge potential disadvantage should it lead to getting caught and killed by the predator, or failing to catch the very food that might keep us, and our dependents, alive. The benefit of the analgesic / hedonic effect is that if a person is running to save their skin, then switching off the pain signal and inducing a light high to further compensate for any residual pain resulting in an unimpeded getaway makes perfect sense. Better to endure minor tissue damage if it is the only way to ensure you’ll live to see another day.
There is a huge amount of evidence to support the concept that regular exercise is extremely good for body and brain. The trouble is, we all know this but few actually get around to taking regular exercise. In my view the main reason for this is partly feeling overwhelmed by their busy lives but also probably involves exercising in the wrong way: when people do finally get around to exercising they often overdo it. Spending the whole of the next day aching all over will do little to incentivise them to take the trouble to exercising again any time soon.
I would argue that little and often is the best policy. Even at the frantic pace of modern life everyone can fit in 20-30mins of exercise a day. That way, even if some weeks you only hit 50% of your target, you’ll still be getting your heart rate and breathing rate up, flooding the brain with highly oxygenated blood, endorphins, endocannabinoids and BDNF, 3-4 times per week – exactly the recommended dose!
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Mnemonic Techniques by Dr Jack Lewis
There are a wide variety of mnemonic techniques that have been developed over the centuries, some more sophisticated than others. The first memory trick I was ever gifted was: “Richard-Of-York-Gave-Battle-In-Vain” which my primary school teacher taught the class to help us remember the order of the colours of the rainbow.
The first memory trick I ever made up, aged 14 or so, was “purple cof gas” – a memorable mnemonic for me personally because it conjoured up an image of Batman being knocked out with a big plume of noxious, magenta vapours spewing from the tip of the Joker’s umbrella. It was a vivid way to remember some relatively dull facts for when my biology exam came around: the system of classification for living organisms. Every one knows about the Kingdoms, we’ve all heard of the animal kingdom and the plant kingdom etc. But Purple COF GaS enabled me to remember, even now 18 years later, that the correct order for the rest of the classification system was: Phylum, Class, Order, Family, Genus, Species. I had a test that asked about the classification system on several occasions over the years and it was Batman and the Joker that helped me get full marks in that part of the exam everytime, effortlessly…
A useful little trick, but not terribly sophisticated or flexible. The “Memory Palace,” on the other hand, has been exploited since the Romans and Ancient Greeks. A time when poets were expected to recite 5-hour long poems from memory, word-for-word, or end up meeting an untimely demise.
It involves using a personal “Memory Palace” based on a real place that you know like the back of your hand. Each room is visited sequentially and each place and/or piece of furniture within that room visited in a specific order. This provides a mental framework in which to-be-remembered items can be “placed” to enable perfect recall when the journey is repeated in the imagination. However I’ll return to the Memory Palace at a later date in favour of explaining in more detail one that is fantastic for remembering a simple list. A list of historical events, a shopping list, a list of names, a list of points to be raised in a meeting – whatever you like. If you want a way of memorising a list so you can bring the items to mind in exactly the right order, then what I call the chain mnemonic is a great starting point.
The chain mnemonic involves vividly imagining multisensory “pairs” of memories in a manner that creates successive links between one item and the next to form a chain. I’ll walk you through an example to demonstrate how useful it can be in retaining lists of information that must be recalled in a specific order. Lets say for instance that you wanted to commit to memory every team that has won a football World Cup since its inauguration (in reverse chronological order):
West Germany (1990)
West Germany (1974)
West Germany (1954)
The first challenge is to dream up a memory for the first link in the chain i.e. using your imagination to make an association between Spain and Italy that is personal to you. You create a symbolic representation in your mind’s eye for each of the two countries and then you combine them. Simple. When I personally think of Spain I think of bullfighting and matadors. When I think of Italy I think of pasta. So to create an unforgettable link between the two I imagined an action-packed, movie-esque scene with lots of bullfights and spaghetti:
Link number 1 in the chain: Spain (2010) –> Italy (2006)
A bull gushing blood (emotionally charged – shocking, disgusting etc) is charging towards the matador (fear, horror) at the centre of the bull ring. The light is glittering off his garishly decorated outfit (visual sense), the crowd is roaring their approval (auditory sense), there is an overpowering stench of sweat, dust and blood (olfactory sense), but at the moment the bull reaches the matador I realise (horrified) that the cape he is weilding is not made out of cloth, but of strands of spaghetti (emotion: strange, bizarre, worrying – HE’s GOING TO DIE!!).
The matador’s sword delivers the final death blow at the moment that the bull’s horns strike the cape – ripping it to shreds and sending an explosion of spaghetti up into the air (highly exaggerated bizarre image – see left – almost like something out of a cartoon). As the bull dies it’s twitching and tossing sends more and more spaghetti into the air. This is the key image that successfully intertwines the concept of Spain with Italy – the convulsing bull spreading unfathomable quantities of spaghetti all over the bull ring. Picture this vividly, emotionally and in a multisensory fashion and you will never forget it. The spaghetti splatters the matador from head to toe, it flies high up into the sky and showers down upon the noisy crowd who are finding the spectacle hilarious (emotion: bizarre, unreal). This might seem unnecessarily elaborate, weird and harrowing – but this is what makes the memory memorable. Matador/bull = Spain (winners of the 2010 World Cup). Spaghetti covering the whole bull ring = Italy (winners of the 2006 World Cup). We have successfully created the first link in the chain. Now we have to create the second link in the chain.
Second link in the chain: Italy (2006) –> Brazil (2002)
As I’ve mentioned, it is really important for these memories to be relevant to you personally. For me, something that sticks out in my mind about Brazil is that Brasilians absolutely love to eat barbequed chicken hearts. When I first set eyes on a skewer of chicken hearts it turned my stomach (but as with many things, I ended up loving them in the end). I find piggybacking my mnemonic symbol for Brazil onto a real memory THE most effective way to make it stick. The emotionally-potent real event that I’m think of is when a waiter came over to our table in a Churrascaria (Brasilian restaurant where the waiters constantly circulate with hot meat fresh off the barbeque) with a disgusting-looking skewer of 40 or so chicken hearts. I was coerced into trying it and I’ll never forget seeing the waiter saw ten or so frazzled chicken hearts onto my plate. Everyone must find their own symbolic representations that are emotionally charged and inextricably linked to the item that you’re trying to remember, but the charred chicken heart episode is my personal symbol of Brazil (disgulpa!).
So link number 2, at least in my World Cup chain mnemonic, involves our matador, starving hungry (emotional drive) after a long and arduous bullfight (he’s exhausted), scooping up an armful of spaghetti from the floor all covered in blood and dust (disgusting) and plonking it on a plate at a table that has been ceremonially placed at the very centre of the bull ring. As Ronaldinho (a very famous Brazilian footballer for those who don’t follow soccer) dressed as a very formal waiter (bizarre spectacle) with his big goofy teeth (emotion: humorous) approaches the table wielding a skewer of chicken hearts in one hand (emotion: disgusting, stomach turning) and a big knife in the other (emotion: threatening).
He politely bows to the matador who signals that he wants some hearts on his plate and so Ronaldinho saws off every single chicken heart one by one onto the top of the pile of spaghetti. This is the image that forms the core of link 2: a big knife wielded by a slightly deranged-looking Brasilian footballer (scary/funny), cutting many more chicken hearts than you could ever eat in a lifetime from a BBQ skewer (disgusting) which tumble down the sides of the big pile of dusty bloody oily pasta glistening in the sun (unappetising). We have now created link number 2: Pasta = Italy (winners of 2006 World Cup) and Ronaldinho depositing chicken hearts onto the plate = Brazil (winners of 2002 World Cup).
This process continues all the way through the list. Link number 3 in the chain: Brazil –> France, for me, would involve a revolting scene whereby some of the chicken hearts sprout antennae and start crawling off the plate and leave disgusting looking slug trails all over the table. Chicken hearts are about the same size as a snail and not-dissimilar in texture, so the main image here is the chicken heart (symbol of Brazil) miraculously metamorphosising into a snail (symbol of France).
Once a chain of mnemonics has been imagined and elaborated: linking item 1 to 2, item 2 to 3 all the way to the end of the list – it must be revisited. Shut your eyes and imagine the sequence of events from link 1 to 2 to 3 and if you get stuck re-rehearse the transitions that you’re not remembering well. I cannot emphasise enough how important this step is. Focus on isolating weaknesses in the chain and making them more memorable by imaging more disgusting, horrifying, inappropriate or erotic (yes erotic – if it’s risque you’ll remember it even better) scenes and/or adding more imagined sensory information to the scenario to ensure perfect recall. From time-to-time you will have to change the symbolic representation for an item so that it fits into the flow of your chosen narrative, or you might have to change the story a little bit to make it work. Once these imperfections in recall have been identified and fixed, you’ll find that you can roll off the list of items no problem in no time at all – amazing your friends, family and colleagues with your gob-smackingly-good memory.
It may seem like a lot of effort to begin with. However, as with all things (see here for more) the more time you spend experimenting with your imagination the faster, better and more efficiently you’ll be able to create and recall the memories. After a while you’ll be able to sit down for 10 minutes with your list of to-be-remembered items, be it a shopping list, or points that you want to raise in a meeting or during a presentation without using prompts, and you’ll nail it every time.
MEMORY AND THE BRAIN – going deeper into HOW and WHY these mnemonics work so well…
The successful creation of memories relies upon a densely packed and highly interconnected network of brain cells called the hippocampus residing deep within the temporal lobes.
We know that the hippocampus is vital for the formation and retention of memories because when it is damaged, by oxygen starvation resulting from ischaemic or haemorrhagic stroke, encephalitis, certain types of epilepsy or Alzheimer’s disease, people become amnesic.
The hippocampus is so named because if you take cross-sectional slices of the temporal lobes, which run horizontally along the left and right sides of the brain, it looks like a seahorse (In greek “Hippo” means “horse” and “campus” means “sea”).
The hippocampus nestles inside the medial or “inward” facing part of the temporal lobe, which is a key component of the emotion-producing limbic system. So the first tip to creating memories that are easily and effectively recalled is to ensure that they incorporate some kind of potent emotion. More on this later.
The hippocampus is also highly connected to all sensory areas. Visual brain areas at the back and underside of the brain that make sense of the light that strikes the retina at the back of the eyeball feed into the hippocampus. Auditory brain areas on the upper portion of the temporal lobes that create the sounds that we hear send millions of neuronal tendrils through the hippocampus. Touch information coarses down from somatosensory areas located within regions of the parietal cortex right at the top of the brain. Tastes feed in from brain stem regions involved in processing chemical stimulation of the tongues taste buds. And smells feed directly in from the olfactory bulb directly above the nasal cavity. Consequently, the second tip for creating memories that are swiftly and faithfully recalled is to make them multisensory. So with any mnemonic strategy you must commit items to memory not just by imagining what it would look like, but also what would it sound like, smell like, feel like and taste like too. This makes them much easier to recall than unisensory memories – those that exploit only one sense. This is because multisensory memories are embedded not only in connections from the different sensory areas to the memory forming and recalling hippocampus, but also in connections between the different sensory areas. Multisensory memories are more powerful than the sum of their parts.
Emotionally-labelled memories are given special priority treatment when it comes to recall because the amygdala, a structure densely connected with the hippocampus and residing at the tips of the medial temporal lobe, becomes activated when the brain is processing emotionally-significant information, imprinting it with HIGH STATUS. The amygdala is most famously involved in the fear response, in which it responds to sensory information indicative of a threat to life and limb, by mobilising body and brain to fight or flee the danger. More recently it has been discovered that it becomes activated by stimuli that induce positive as well as negative emotions, so long as they are potent. Presumably the reason that the mechanism for making emotional inducing stimuli and events more memorable evolved is because, for the event or scene to have produced a strongly positive or negative emotional response, then it is likely to be useful to be able to recall it in the future to guide our behaviour.
So, bear THIS in mind: when dreaming up these mnemonics…
- a disgusting scene such as someone you know vomiting in front of you
- a funny scenario that makes you feel genuinely amused inside
- or, perhaps, an “inappropriate” scenario such as walking in on your boss, your teacher or your parents having sex
…will be much more effective in ensuring recall than emotionally-neutral scenes. Don’t forget: as well as being multisensory in nature, your imagined scenarios must be emotionally-charged.
If you find this useful and/or interesting it would be really great if you could take the time to write a comment. I don’t get paid for this and it’s very time consuming. I do it because I’m passionate about the brain and want to share this passion with the world. So prove yourself to be one of the determined few who got right the way through to the end and please do me a favour by letting me know you’re there and leaving a comment.
All the best and enjoy expanding your mnemonic abilities, DrJ
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From adolescence onwards we all begin to lose brain cells. As a consequence our brains gradually and inexorably shrink (compare the “old” brain on the left to the “young” brain on the right). In fact by the age of 80 your brain will occupy 15% less of the space within your skull than in the prime of life. Yet over the course of adulthood, as our brains are losing more and more cells, our knowledge and repertoire of skills nonetheless continues to grow as we accumulate more and more experience. How is this possible? Well, despite the incremental decrease in quantity of brain cells over the years connections between neuronal networks that are in regular and intensive communication with each other are selectively reinforced. This enables increased efficiency in execution of the mental processes that those networks support. Hence we can do more with less as we age. Sadly, for all of us, there will always come a time when the degree of brain cell loss is such that mental function begins to decline. In other words, if we all could live forever, dementia will inevitably strike at some point in time.
Although we cannot halt the process of grey matter loss completely, the good news is that we can slow down its progression. This month a study conducted at the University of Pittsburgh and published in the journal “Neurology” describes the influence of regular exercise on the rate of reduction of brain volume and cognitive function in 299 elderly individuals.
It was observed that those individuals of this group of average age 78 who walked in excess of 6 miles per week had a significantly reduced rate of grey matter loss and consequently a lesser degree of cognitive decline. The greater the distance walked each week, the smaller the reduction in volume over a 9 year period within their frontal lobe, occipital lobe, entorhinal cortex and critically, in the hippocampus. My post last month described the vital role that the hippocampus plays in the creation and recall of long term memories.
This begs the question – how and why does exercise slow down the rate at which grey matter shrinks? An exciting possibility is that all that walking might actually increase the rate at which new brain cells are created; a process known as neurogenesis. This boost in the creation of new brain cells might help to compensate for the loss of old brain cells. Evidence to support this hypothesis comes from research conducted over a decade ago suggesting, in the mouse brain at least, that exercise does indeed increase the rate of neurogenesis.
Exactly why this happens is unclear, but I would propose that, given the hippocampus is heavily involved in navigation, particularly when it comes to flexibility in finding the best route from A to B, it would make sense for physical activity to trigger production of new cells in this brain area. A greater number of hippocampal neurons would presumably support a greater capacity to memorise routes and landmarks encountered whilst exploring the environment. This could feasibly convey a critical survival advantage by helping to prevent people from getting lost. Over the thousands of years of our species evolultion, getting lost was probably an excellent way of deleting oneself from the gene pool and so those with movement-triggered hippocampal neurogenesis may have been more likely to survive.
This seems a plausible (but by no means concrete) account of why older individuals who take regular exercise appear to have more grey matter and superior cognitive function than those who do not. Whatever the true explanation, it seems clear if you want to hang onto your marbles in the long term then it’s probably a good idea to take a regular stroll for the rest of your life.
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The terminology associated with brain anatomy can seem intimidating to the uninitiated, but really there’s no need to be intimidated.
A pair of cartoon rodents (Pinky and the Brain) managed to get their heads around it and so will you.
Here’s their quick guided tour to the different parts of the human brain.
It’s a shame they don’t really mention the role of each area they name.
I guess that would have made making the lyrics rhyme even more complicated!
To supplement their guide to neuroanatomy (what bit is where) I’ve given a quick overview of what each bit does in the order they’re covered in the cartoon:
1) Neocortex – the whole large sheet of brain cells on the brain’s outer surface, folded up into the skull giving it the appearance of a walnut.
2) Frontal lobe – the region of the neocortex at the front of the brain, behind the forehead, which is much larger in humans than our monkey cousins and enables us to do all those complex functions that other primates cannot.
3) Brainstem – the part of the brain that ninja assasins aim for with their deadly chop where neck meets skull, it is involved in coordinating all the vital bodily functions that keep us alive e.g. breathing and heart rates.
4) Hippocampus – key brain area at the core of the temporal lobes (which run horizontally down the sides of the head from the temple to behind the ears) which is heavily involved in not just creating, but also retrieving memories. It also creates new brain cells in response to exercise!
5) Neural node – erm, I think they just needed something sciency sounding to rhyme with the other lines. The image THE BRAIN enlarges with the magnifying glass is a single brain cell complete with nucleus (which contains all the DNA) at it’s centre, the dendrites (receiving information from other brain cells) plus a single axon (along which electrical messages are sent to other brain cells).
6) Right hemisphere – the left and right sides of the neocortex are separated by a fluid filled gap yet are connected by a massive bundle of neuronal connections called the corpus callosum that bridge the gap enabling left and right sides to send and receive information between them.
7) Pons – All of the commands travelling from parts of the neocortex involved in motor control (i.e. body movements) pass through the pons which sits on top of the brainstem which is at the very top of the spinal cord through which the brain controls all the muscles of the body.
8) Cortex visual, usually referred to as the visual cortex, sits right at the back of the brain. So the eyes quite literally detect light striking the retina, at the back of the eyeball, and send this information all the way to the back of the brain before we can see anything!
9) Pineal, usually referred to as the pineal gland, is about the size of a grain of rice and produces melatonin which regulates the sleep/wake cycle. Daylight in the morning switches off melatonin production to make us feel awake, switching production back on in the evening so we can sleep.
10) Cerebellum left and right, critical for balance and co-ordinated muscle contractions important for effective speech, walking, running, swimming and all sporting activities etc.
11) Synapse – the gap between one neuron and the next. Electrical signals arriving at the end of one neuron releases tiny packets of brain chemicals that travel across the synapse, bind with special receptors on the other neuron to trigger or inhibit electrical signals its own electrical messages.
12) Hypothalamus – the most important site of hormone production and release that powerfully regulates innumerable body and brain functions.
13) Striate, a. k. a. striatum – enormously important subcortical brain area (deep in the brain not on the surface of the neocortex) involved in reward and motivation, planning and modulation of movements, named thus due to its stripy appearance.
14) Axon fibres – as mentioned before this is the part of the brain cell that sends electrical messages to other brain cells.
15) Matter grey, usually know as the famous Grey Matter. This is darker than the white matter as this is where all the synapses and cell bodies are. So it is in the grey matter that all the computational power of the brain is unleashed.
16) Central tegmental pathway: the tegmentum is a part of the midbrain – which lies between the striatum and the brain stem. Activation of the ventral tegmental area, i.e. the “belly” of the tegmentum, causes the feelings of intense pleasure when people eat, drink, have sex or take drugs.
17) Temporal lobe – the upper surface of the temporal lobes is the part of the brain we hear with.
18) White core matter, usually referred to as White Matter, consists of millions and millions of axonal fibres that ferrying electrical signals from one brain area to the next.
19) Forebrain – we’ve done that already
20) Skull – the bone in which our brain is cradled
21) Central fissure – the name for the fluid filled gap described earlier which separates the left and right hemispheres
22) Cord spinal, usually known as the spinal cord, through which axons pass sending messages from brain to body and body to brain.
23) Parietal – one of the lobes of the neocortex – involved in spatial awareness, focusing attention and mathematical calculations.
24) Pia mater – is the innermost of the three brain sacks (or meninges) which cushion and protect the brain.
25) Meningeal vein – blood vessels taking waste materials away from the outer parts of the neocortex.
26) Medulla oblongata – lower part of the brain stem, also involved in triggering reflexes like vomiting, sneezing, coughing etc.
27) Lobe limbic – usually known as limbic system, deep inside brain beneath the temporal lobes, involved in generating emotions.
28) Microelectrodes – there is not a microelectrode in sight so just ignore that lyric!
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