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Lessons

2g - Memory

Posted by Helen St Clair Tracy in Level 2 - How The Brain Learns
Published: 07/03/2019, 12:53am | Updated: 15/03/2019, 3:46pm

Video Link: https://vimeo.com/323250870

Our stored memories are located mostly in the cortex of our temporal lobes.

Stored memories are mostly located in the temporal lobes.

When you are born, whilst there are certain things you are 'pre-programmed' to do without being taught, like breathe, and blink if something approaches your eyes fast, you do not have any memories (although some babies may have memories of music and voices from the womb).

We are born a bit like a blank sheet of paper, or maybe the foundations of a wall, without any bricks laid upon it yet.

The human brain is pre-programmed to learn, and as soon as you are born, your brain starts learning, from the experiences around you

Where an experience is consistent, it is learnt quickly, for example the sound and feel and smell of the baby's mother.

And this knowledge of our mothers, and fathers, and siblings and anyone else regularly close to us, including family pets, will be amongst the first memories we create. As these memories grow they become more complex, in that they have more layers, from more and more experiences.

A complex memory is one that has many different elements to it, and grows and evolves over time. A mother for example is initially simply known, and may be a source of nourishment if breastfeeding. Over time, the comfort of a mother makes the baby feel safer and in turn that makes the baby feel happier. This motivates the baby to want to be with their mother. The baby already has an understanding of the reward (as explained in lesson 2e)

A stranger in the house, who holds the baby differently, and does not sound or smell the same as their mother may not get such a warm reception from the baby.

Think of that baby's extremely limited knowledge:

Mother =

  • Known
  • Source of food
  • Source of comfort
  • Source of feeling safe and happy

Stranger =

  • Unknown

Which of the two do you imagine the baby will want to be with?

And in these very early learning experiences, more complicated learning experiences are taking place, putting things together to gain greater understanding. The stronger, more complex memories of the mother create a strong sense of motivation. Equally, the baby already has experienced and decided they are not motivated by the unknown. With the unknown, the reward is missing.

For this baby, the foundations of their wall now has a few bricks.

This is a very simple explanation, but key is understanding that the memory is formed from the experience, and where an experience is repeated, the memory becomes stronger.

There are many different types of memories stored in the brain, including:

  • Visual memories of what things look like
  • Sound memories, including memories of tunes
  • Touch memories, of what things feel like
  • Smell memories
  • Taste Memories
  • Haptic memories (see shoe laces example below) combining experiences from touch and other senses.
  • Word memories, from combined senses including hearing and vision
  • Speaking memories - how to say different words, combining other senses including sound, sight and haptic
  • Emotional memories, memories attached to strong emotions, what we like or don't like, what makes us laugh and what makes us cry or angry or scared.

The list is endless as the initial simple experiences join up, to create more complicated memories, and new experiences are combined with existing memories from previous experiences. This all helps us understand the world around us.

Emotional Memories

Memories connected with an emotion can be particularly strong. Think back to your childhood and try to remember an event, any event. Of the tens of thousands of hours of your childhood you could have recalled, it is likely you are thinking of something that has a strong emotional connection. Something that made you happy and fall about laughing maybe, or something that may have frightened you or made you very sad. In a future level we will be looking more closely at the development of emotions and how CVI affects this.

Memories fall into two groups of short term memories and long term memories.

Short Term Memories

These help you to remember what you are doing, so if you are making a cup of coffee and get some milk, it is your short term memory that keeps all the information together about what you are doing. Sometimes you may have found yourself going to fetch something, then forgetting what it was you were looking for or why - this would probably be your short term memory not working so well, and it can be affected by many things including feeling tired, or very distracted. To make sense of this sentence, your short term memory holds the words at the beginning, so these words at the end make sense to you.

A part of the brain that is key for the short term memory is called the hippocampus.

The hippocampus, here shown in orange, forms a sort of seahorse shaped loop.

You have two hippocampi, one on each side of the brain. The hippocampus wraps itself around in a sort of seahorse shape (hippocampus means Seahorse) on the image above it is shown in orange, the small oval area at the bottom is the other end of the main part, indicated with a black arrow.

One group of people commonly affected by CVI are babies who are born prematurely, or where there are complications during pregnancy or at birth affecting oxygen getting to the brain, or where there is very low blood sugar (hypoglycaemia). Research has also shown that in this same group, there is a higher than average rate of damage to the hippocampus. This means that those affected may have difficulties with their short term memory.

Here's where things get tricky, because short term memory loss can look a lot like issues with attention, making someone seem extremely distracted, as is common with the condition ADHD. CVI, as we will explain, also affects attention, in many different ways. It is very easy to end up in a great big muddle about what is causing what! Here we stress again, that the approach to understanding has to be completely personal to the person with CVI.

Long Term Memories

These are the building bricks we have referred to in your wall of knowledge. You use your long term memories to make sense of what you are doing, whilst using your short term memory.

Think about tying your shoelaces.

When you first learnt, it is likely that the only skill you started with was being able to hold the lace between your thumb and index finger. That is called a pincer grip, and is something you would have learnt, so your pincer grip is one brick.

You can see and recognise the laces on the shoe - so that is another brick, you know what shoes are and what the laces are for.

As you learn to tie your laces, the early attempts will be frustrating and difficult and probably unsuccessful - you are trying to build new bricks onto a layer that is not strong enough, but with each attempt, the bricks get stronger and stronger, until you can confidently tie your laces, even being able to tie your laces without looking at them.

  • Your short term memory is needed to tie the laces, and remember why you are tying them (to go outside maybe).
  • Your long term memory provides you with everything you need to actually tie your laces.

Your short term and long term memories are quite different therefore, but work together, and need each other.

This skill, to tie your laces, where your sense of touch, supported by other senses, particularly vision, educates your movement, speed and muscles, so you know how much pressure to apply, when gripping the laces and tying them, is called haptic memory.

So memories are complicated, and, in line with our experiences, often combine many different senses.

Problems With Memories

A memory can be wrong, or unreliable or simply absent for different reasons, including the following three:

1) The existing memory is affected due to an injury or condition, for example dementia.

Here, CVI could be also present. It is estimated that 40% of the brain is dedicated to visual processing, this means that there is a good chance that any injury, disease or infection altering the brain, is likely to affect a part responsible for visual processing.

2) The short term memory is affected

Here, as we briefly explained, some groups of people ,where there is a high chance of CVI being present, may also have short term memory loss.

3) The formation of the memory is flawed, due to something in the experience process.

Here, we know CVI creates particular difficulties, where the experience is not good enough to form strong memories.

Do you recall the lotus flowers from a previous lesson?

How much harder would it be to learn what a lotus flower is where vision is impaired?

Where vision may be absent, for example due to eye blindness, or reduced, due to other conditions, people can very effectively learn to use their other senses and learn in different ways to do things very well.

CVI is different.

Although in many people affected by CVI, vision is impaired, there is not necessarily a lack of vision or even reduced vision. With CVI what you see can be:

  • Inconsistent
  • Overwhelming
  • Unreliable
  • Untrustworthy
  • Stressful, even frightening

And this creates different challenges to learning. It is adding further difficulties to the learning process, by also making the experience inconsistent. So, when the lotus flower is seen several times, what is remembered may be different each time, so it is not learnt or is much more difficult to learn.

The solution is to understand how the person's vision is different, and then to match the teaching to the known challenges.

Example

For example, to teach what a lotus flower is, to a child with language learning difficulties, first think how a memory can be most powerful, especially if there may be a short term memory issue - attach it to a strong emotion. Emotional memories work both ways, and the happy ones are as powerfully positive, as the distressing ones are negative, or interfere with memory formation.

So, firstly, plan to create a fun happy environment:

  • Who would that be with? Someone well known and liked.
  • Where would that be? Somewhere known, quiet and uncluttered.
  • What time would that be? A time of day when the person with CVI is not tired, hungry or otherwise distracted.

Introduce one lotus flower on its own, using the words 'lotus flower' - and repeat - just like learning to tie your laces, when learning something new, particularly if difficult, the bricks are still weak. Consistent repetition is key. Let the person feel it, bring it to their mouth to explore, repeating only two words 'lotus flower', spoken very slowly, like an old record playing on a slow speed. Take as much time as the activity is of interest. The first time this may only be a second or two, but the next time it may be five seconds, and so on. Always stop when the person loses interest - remember that emotional memory attachment - keep it positive, the happier the experience, the stronger the memory.

Then, when out and about, and you see a lotus flower, point out the flower and use the name, and over time, combining the consistent experience with the consistent word, the person with CVI will learn more and more that what they are looking at is a lotus flower. You are creating a memory and a pathway between the visual memory and the word. That is neuroplasticity.

With CVI, the memory of the word to match the visual experience can be extremely important, and we will follow this example into the next section on Recognition, and explain why, without a word or other way for the brain to label what it is looking at, vision can be extremely confusing and make no sense at all for a person with CVI, particularly children born with the condition.

Checklist:

Before you move on to the next level, please check:

  • You understand some of the different types of memory
  • You understand the difference between short term and long term memories.
  • You understand some of the challenges to memory, and with CVI a particular difficulty is the experience may not be complete.
  • You understand why visual experiences for a person with CVI can cause additional challenges to learning.
  • You understand why, in relation to how the brain learns, the learning environment should be happy and positive.

Next lesson: Level 2h How the Brain Learns - Recognition

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