The ageing brain

THE AGEING BRAIN

Our brain is not a fixed entity, it is designed to develop and change, adapt. And respond throughout life. The average brain has about 85 billion neurons which are in constant flux. The same number of non-neural cells are called glia and these are the waste management infrastructure.

The neurones are woven together into a network of communication which determines who we are, what we think and how we feel. If the communications and connections fail, that part of the brain will die.

A synapse is a gap between the axion of one neuron and the dendrite of another neuron. The communication across the synapse is via an electrical signal called a neurotransmitter eg dopamine, serotonin, glutamine . The strength or weakness of the connection between the synapses determines how we retain memories and the ability to walk and talk .

Neurologically speaking “ Cells that fire together, unite together”. Meaning that the more you use them the stronger they are.

Neuro plasticity means that the neural connections can grow and change through learning and new experiences throughout life. Using our brains more increases its growth and is essential for neuroplasticity. Take for example the London cabbies who " learn the knowledge” of every street in London which was an enourmous undertaking of many years of training. These cabbies had bigger Hippocampus than other people and musicians have more grey matter in the motor cortex. The more practice the more growth.

This plasticity will show in stroke patients even though part of the brain has been starved or oxygen and has died a new part of the brain can learn the processes and grow new neural connections.

Good sleep helps to consolidate these neural connections .

Cognitive processes decline after the age of 30 , however with age also comes the increase of knowledge, expertise, emotional stability, language and verbal abilities.

The decline with age includes ;

A reduction in the brain's processing speed ( rather like an old computer )

The ability to pay attention , we may be more easily distracted

Emotional decision making reduces and we become more gullible, we assess risks less accurately. ( hence more of the elderly being scammed)

Common brain changes are the slowing of the neurons because the myelin sheath that insulates the axion degrades and the message passed along the neuron slows down and even disappears. The pre-frontal cortex ( emotions, attention, impulse command centre) and the hippocampus (memory centre) both show less activity and reduce in size. The connection between these two centres slows down and neurotransmiiters become depleted. This is all part of normal brain changes over time.

Early Alzheimer’s causes disorientation about time and place ( where am I and what am I doing). Memory problems and doing things like putting the keys into the freezer, forgetting familiar things , planning and problem solving is difficult.

Alzheimers occurs because of the disruption between synapses and a build up of protein called Amyloid plaque which damages or eats away at the synapses or the neuron itself. This causes the formation of Tau tangles. This is called a neuro-inflammatory response caused by the release of Microglia which are the brain’s housekeeping squad. This builds up even more plaque and starts to fight even healthy neurone and synapses termed Neuro degeneration.

Beta amyloid is the match that light up the Tau Tangles that then cause the neuro inflammatory response which becomes the bush fire.

Why do some people get dementia ?

There are some things that increase your chances.

1. Being between 65 and 69 years of age you have a 1 in 70 chance, over 85 years a 1 in 3 chance.

2. Your genes might play a role although this is rare.

3. Other factors such as high blood pressure and high cholesterol, diabetes, obesity and smoking. Declining hearing and depression are also factors.

Some health and lifestyle factors can decrease the risk.

1. Learning, mental activity, life experiences, education and a challenging work environment.

2. USE IT OR LOSE IT build a resilient brain by putting it to use.

3. Socialising is quality brain food. Cognitive behaviours are enhanced by social interaction.

4. Exercise boosts oxygen delivery and stimulates feel good hormones such as dopamine and serotonin. This is particularly useful for people suffering from stress and mental disorders.

5. Meditation due to less cortisol from the stress response. Yoga and Tai Chi have a meditative effect as well as being great for balance, stretching and breathing .

6. Sleep. The brain cleans up while we sleep and this is called neurological maintenance. It is highly beneficial for memory formation and brain health.

The best things that you can do to reduce your risk of developing dementia are to take control of your lifestyle factors as listed above.

There are new screening tests for dementia and some medications can slow the process of decline , but the effectiveness of these is some way off being mainstream and with some people developing dementia before middle age, the sooner you take control of the ways you can influence your risks, the better.