Everyone’s brain is constantly growing including those living with an intellectual disability.
Human brains do a lot of growing from childhood to adolescence. We learn to walk, learn to speak, start to recognise other people as sentient creatures, and begin contemplating how the world works. Scientists believed for a long time that our brains stopped growing once we reached adulthood. “You can’t teach an old dog new tricks” as the adage would go, or “a leopard can’t change its spots”. We now know that isn’t true. Instead, our brains stay malleable throughout our lives, adapting to stimuli from our environment, lifestyle, behaviours and even our thoughts and feelings. This knowledge has helped us treat neurological-related conditions like PTSD and Parkinson’s, and aided people with a wide range of disabilities. And with the right mindset, all our brains can continue to grow long into old age.
The human niche
You wouldn’t think we have big powerful brains given how vulnerable our infants are. Human babies are wholly reliant on their parents for years after birth. While baby sea turtles can find the ocean moments after hatching and newborn cows are upright minutes after taking their first breath, our quirky children can do little more than keep their eyes open. Although other primate species also rely on their parents, for human infants to be born with a similar function to a chimpanzee newborn they would have to stay in gestation for eighteen to twenty-one months (1). It seems like a risk to have such vulnerable young, but that’s the trade-off we made for our adaptability.
Most animals don’t need big brains because they find niches to occupy in the animal kingdom. Niches refer to how well a species fits into its environment and take advantage of resources. Humans also have a niche, however, ours is niche-switching. We can move to almost any location on the planet, with any food source, and adapt and thrive in that environment (2). That’s because of our big brains and its ability to reorganise its structures and functions in response to stimuli, a trait called neuroplasticity.
What’s in a brain?
Before we get into how to grow our brains, let’s lay down some groundwork to understand how our brains develop in the first place. For all the technological advancements we’ve made in the past hundred years, nothing compares to the complexity and power of the human brain. It is like a supercomputer with many specialised regions dedicated to sight, movement, memory, and emotion.
Neurons are messengers of the brain carrying information to these different regions and across your nervous system. Your skull is full of them, clustered in different areas like the amygdala which processes emotions, and the cerebellum that is involved in motor learning and the maintenance of posture. These messengers communicate through junctions called synapses, like phone wires connecting each neuron to its neighbours. Every thought you have and every physical or emotional thing you feel is thanks to the connections between your neurons.
Grow
Given how important neurons are you’d think we’d be born with all the neurons we need. Instead, we’re born with brains running at a fraction of their true capacity with many underdeveloped regions. While our DNA has the information to make a fully formed brain at birth, the genes to form a complete brain “switch on” at different stages of our development. Beginning three weeks into gestation (3), progenitor cells (cells that could be anything) differentiate into specific brain cells like neurons, a process called neurogenesis. The brain continues to grow after birth, doubling in size in the first year and reaching 95% of its adult volume by the time a child is six-years-old (4).
Prune
Synapses continually form through to adolescence and the brain is a packed house by the time we reach puberty. The adult brain has an estimated 100 billion neurons, and each neuron has up to 40,000 synapses between them, which means a teaspoon of brain matter has more connections than there are stars in the Milky Way Galaxy (5). It can be metabolically taxing to maintain all these synapses. To make the brain more efficient, it removes synapses that aren’t being used and strengthens connections that are, processes called synaptic pruning and myelination.
Does the brain ever stop growing?
The prefrontal cortex is the last part of the brain to develop after adolescence as it’s the area most associated with abstract thought, requiring other areas to develop first. Its delay in development is argued to be a reason why teenagers have such poor impulse-control—this is hotly debated so we’ll let you decide if this is true or not—. Scientists also believed that our brains did not change much after the age of twenty-five. However, we now know that the brain is continually making changes throughout our entire lives.
Researchers have found that the corpus callosum, a stretch of verve fibres connecting the two hemispheres of the brain, still grows well into our forties. And the Journal Stem Cell observed that the brains of 80-year-olds show just as much neurogenesis as teenagers (6). In fact, an estimated seven-hundred new neurons are being created in the hippocampi of elderly people every day (7), and this is an area that is critical for memory formation and emotional regulation. Knowing this, we can better treat psychosocial conditions like post-traumatic stress disorder (PTSD) and depression and learn new insights into conditions like epilepsy. We may even be able to consider preventative treatments for Alzheimer’s as detecting a decline of neurogenesis in living brains—if it can be done without requiring a dissection—could provide doctors with an early warning sign of the disease (8).
How can neurogenesis help people with disabilities?
Research suggests that promoting hippocampus-neurogenesis can reduce the anxiety of people living with down syndrome while improving learning and memory (9). Evidence also shows that neurogenesis in the hippocampus is essential for memory separation, allowing us to distinguish between two closely related events (10). A lack of neurogenesis in this area could explain why people living with PTSD continually relive traumatic experiences, and people with major depressive disorder (MMD) and anxiety find themselves in loops of negative thoughts and emotions. Promoting neurogenesis has been shown to alleviate these symptoms and increase a person’s resilience to stress (11).
Increasing neurogenesis: how to grow our brains?
Growth vs fixed mindset
The first and most important thing we must do to grow our brains is to believe we can. So, we must be sure to start with a “growth mindset”. A growth mindset is a belief that our skills, abilities, and personal traits can be developed strategically through deliberate hard work. By contrast, a “fixed” mindset is the belief nothing about us can be changed in any meaningful way. Henry Ford, the founder of Ford Motor Company, put it best with his take on Confucius by saying…
"Those who think they can, and those who think they can't, are both usually right."
Stanford Psychology professor Dr Carol Dweck, who developed the growth mindset theory, proposed that whether we believed we could make significant changes to our lives impacted how we oriented ourselves to our goals, approached and resolved challenges and responded to criticism (12). This means that we must accept failures as not only unavoidable but an inevitable part of growing into the people we want to become.
Research by Gretchen Marie Hartmann found that students with learning disabilities who were taught skills to develop a growth mindset increased their academic performance and motivation. She watched these students “cultivate awareness of their intellect and embrace new belief skills as they learned about their brains and discussed academic challenges, emotion, and effort” (13). This also applied to the teachers. Teachers who thought their students were competent at a task aligned their teachings to match that belief and would remove barriers limiting a student’s potential.
Tips to develop a growth mindset:
- Convince yourself that change is possible.
- Look for challenges and ask for feedback.
- Invite failure and try again. “Failures are finger posts on the road to achievement.” – C.S. Lewis.
1. Fertiliser for the brain
Now that we have a mindset for success, we can get to some of the practical things we can do to promote neurogenesis and grow our brains.
A sure-fire way to increase neurogenesis is exercise. Researchers at UNSW Sydney found that students who exercise for just five minutes after studying were better able to recall that information than those who didn’t (14). This is because exercise increases brain-derived neurotrophic factor (BDNF), a molecule that promotes neurogenesis by regulating synaptic plasticity (15). Recall how we said the brain either prunes or strengthens the synaptic connections between neurons? The BDNF protein is a major player in maintaining this process and is often called “fertiliser for the brain”. Monash University compiled literature showing that aerobic exercise increased levels of BDNF and promoted hippocampal neurogenesis in people living with MMD, Alzheimer’s and schizophrenia (16).
Some physical disabilities limit the amount of exercise a person can do; however, you don’t need high-intensity workouts to gain many of the benefits of exercise. Clinical studies have found that prolonged low-intensity exercise increases the volume of regions of the brain associated with executive processing in children with cerebral palsy (17). Moderation is key and performing exercises safely will ensure we have the maximum benefit without injury.
2. You put out what you put in
Another way to increase BDNF is by eating foods high in polyphenols such as cocoa, blueberries and low levels of curcumin (also known as turmeric) (18). Omega-3s like those in fatty fish such as salmon are also found to increase BDNF while reducing inflammation, and green tea has been shown to increase neural progenitor cells (precursors to neurons) (19). In short, drink tea and eat chocolate, blueberries, and lots of fish.
Restricting our calories by eating smaller meals, and intermitting fasting, which is reducing the hours in which you eat during the day has a similar effect, and if you’re looking for an overall diet to improve brain growth, many studies have shown that the Mediterranean diet consistently improves cognition and neurogenesis. The diet involves eating lots of vegetables, fruits, and fish, with low amounts of sugar and dairy.
3. A good night’s sleep
Neurogenesis is heavily regulated by our sleep. Disturbances to our sleep can disrupt the brain’s physiology by creating stress and reducing the processes that take place while we rest. Australian researchers have found that cumulative sleep loss dramatically decreases hippocampal neurogenesis and memory-dependent learning (20). We can improve our sleep by:
- Going to bed and waking up at the same time every day, including weekends.
- Reducing exposure to bright light at night, especially the blue light of electronics like phones, TVs, and computers.
- Exercising during the day.
- And avoiding eating big meals before bed
4. Setting and novelty
Finally, If there’s one thing our brains love, it’s novelty. There’s a reason we like eating new foods, watching interesting movies and going on holidays. It’s because the brain thrives when in new and exciting environments. Researchers can stimulate the growth of new neurons in mice models simply by placing them in surroundings that are more cognitively and socially stimulating (21).
London bus drivers who drive different routes every day had bigger hippocampi (important for memory once again) than those who drive the same route every day (22). So, simply going to new places, trying new foods, reading new books, and talking to new people can grow our brains.
Summary
So, who says a leopard can’t change its stripes? The brain might go through growth spurts, but neurogenesis continues throughout our lives and with the right mindset, we can maximise the growth of brains by exercising, eating properly, and getting enough rest. Everyone can benefit from maximising the growth potential of our brains, including those living with a disability.
Raise Your Spirit understands the importance of having a growth mindset and supportive environment. We aim to help others live meaningful and happy lives, so we developed a Disability Performance and Wellness program called The RYS Acceleration SystemTM. This system is a practical at-home guide to help our clients determine the tasks, schedules, and key milestones to maximise their growth. By taking steps together, we hope to see a world where everyone feels great about themselves and their lives.
References
1. Dunsworth HM, Warrener AG, Deacon T, Ellison PT, Pontzer H. Metabolic hypothesis for human altriciality. Proc Natl Acad Sci USA. 2012 Sep 18;109(38):15212.
2. Alexander RD. How did humans evolve? Reflections on the uniquely unique species. 1990;
3. Stiles J, Jernigan TL. The basics of brain development. Neuropsychol Rev. 2010 Dec;20(4):327–48.
4. Fair D, Schlaggar BL. Brain Development. In: Haith MM, Benson JB, editors. Encyclopedia of Infant and Early Childhood Development [Internet]. San Diego: Academic Press; 2008. p. 211–25. Available from: https://www.sciencedirect.com/science/article/pii/B978012370877900027X
5. Xia T. Upconversion nanoparticle mediated optogenetics for targeted deep brain stimulation. Science Bulletin. 2018 Apr 15;63(7):405–7.
6. Boldrini M, Fulmore CA, Tartt AN, Simeon LR, Pavlova I, Poposka V, et al. Human Hippocampal Neurogenesis Persists throughout Aging. Cell Stem Cell. 2018 Apr 5;22(4):589-599.e5.
7. Spalding KL, Bergmann O, Alkass K, Bernard S, Salehpour M, Huttner HB, et al. Dynamics of Hippocampal Neurogenesis in Adult Humans. Cell. 2013 Jun 6;153(6):1219–27.
8. Moreno-Jiménez EP, Flor-García M, Terreros-Roncal J, Rábano A, Cafini F, Pallas-Bazarra N, et al. Adult hippocampal neurogenesis is abundant in neurologically healthy subjects and drops sharply in patients with Alzheimer’s disease. Nat Med. 2019 Apr;25(4):554–60.
9. Stagni F, Giacomini A, Guidi S, Ciani E, Bartesaghi R. Timing of therapies for Down syndrome: the sooner, the better. Frontiers in Behavioral Neuroscience [Internet]. 2015 [cited 2022 Jan 29];9. Available from: https://www.frontiersin.org/article/10.3389/fnbeh.2015.00265
10. Clelland CD, Choi M, Romberg C, Clemenson GD Jr, Fragniere A, Tyers P, et al. A functional role for adult hippocampal neurogenesis in spatial pattern separation. Science. 2009 Jul 10;325(5937):210–3.
11. Becker S, Wojtowicz JM. A model of hippocampal neurogenesis in memory and mood disorders. Trends in Cognitive Sciences. 2007 Feb 1;11(2):70–6.
12. Dweck CS, Yeager DS. Mindsets: A View From Two Eras. Perspect Psychol Sci. 2019 May 1;14(3):481–96.
13. Hartmann GM. The Relationship Between Mindset and Students with Specific Learning Disabilities [Internet]. 2013. Available from: https://books.google.com.au/books?id=t3e7oAEACAAJ
14. Most SB, Kennedy BL, Petras EA. Evidence for improved memory from 5 minutes of immediate, post-encoding exercise among women. Cognitive Research: Principles and Implications. 2017 Aug 23;2(1):33.
15. Huang EJ, Reichardt LF. Neurotrophins: Roles in Neuronal Development and Function. Annu Rev Neurosci. 2001 Mar 1;24(1):677–736.
16. Kandola A, Hendrikse J, Lucassen PJ, Yücel M. Aerobic Exercise as a Tool to Improve Hippocampal Plasticity and Function in Humans: Practical Implications for Mental Health Treatment. Frontiers in Human Neuroscience [Internet]. 2016 [cited 2022 Jan 29];10. Available from: https://www.frontiersin.org/article/10.3389/fnhum.2016.00373
17. Ploughman M. Exercise is brain food: the effects of physical activity on cognitive function. Dev Neurorehabil. 2008 Jul;11(3):236–40.
18. Stangl D, Thuret S. Impact of diet on adult hippocampal neurogenesis. Genes Nutr. 2009/08/15 ed. 2009 Dec;4(4):271–82.
19. Wang Y, Li M, Xu X, Song M, Tao H, Bai Y. Green tea epigallocatechin-3-gallate (EGCG) promotes neural progenitor cell proliferation and sonic hedgehog pathway activation during adult hippocampal neurogenesis. Mol Nutr Food Res. 2012 Aug;56(8):1292–303.
20. Meerlo P, Mistlberger RE, Jacobs BL, Heller HC, McGinty D. New neurons in the adult brain: the role of sleep and consequences of sleep loss. Sleep Med Rev. 2008/10/09 ed. 2009 Jun;13(3):187–94.
21. Trejo JL, LLorens-Martín MV, Torres-Alemán I. The effects of exercise on spatial learning and anxiety-like behavior are mediated by an IGF-I-dependent mechanism related to hippocampal neurogenesis. Molecular and Cellular Neuroscience. 2008 Feb 1;37(2):402–11.
22. Maguire EA, Woollett K, Spiers HJ. London taxi drivers and bus drivers: a structural MRI and neuropsychological analysis. Hippocampus. 2006;16(12):1091–101.
