Child Development: Your Guide to the First Five Years part 2 - The beautiful brain

The use of the word 'beautiful' to describe this structure inside our heads may seem a little strange, but I believe that the brain is indeed beautiful. In Nature magazine (1 November 2007, pp56-61), there is a section describing how researchers in America have genetically labelled neurons with different colours so that they can actually track the different interactions in one small area of the mouse brain.

Comparisons with fairy lights, a city at night or a firework display cannot do justice to the sheer complexity and wonder of the workings of the brain. Just in case you are wondering, the brain of a mouse shares a great deal with our brains, as does that of a primate, a dog, a dolphin - even a reptile.

However, you may be asking why you, as a daycare practitioner, childminder or nanny, need to know about how our brains work. The answer is simple. Our brains are the source of who we are because our experiences, working closely with our genetic inheritance as humans, really do physically shape our brains, influencing our motivation, curiosity, emotional well-being and capacity to play and learn. It is the ultimate springboard of all our hopes, thoughts, dreams, emotions, the way we move and sense the world.

In essence, this means that while every human brain follows the same basic plan for both shape and function, what we meet in our daily lives will dictate the type of connections we make in the brain. For example, if we think of typical development, we all learn to walk at broadly similar ages. However, we will all vary, subtly or more dramatically, in how we actually achieve this, so that in the end, we all walk in a way that is common to humans - upright, facing forward, moving both legs alternately - and, at the same time, in a way that is totally unique to each of us. Some of the factors that could make a difference are:

- Context - where are we learning to walk, type of surfaces

- Encouragement

- Opportunity to both attempt and persist at taking the first steps

- Strength of legs and ability to co-ordinate vision and balance

- Experience, or not, of crawling

- Previous experience - have we been held upright, rocked, bounced, allowed to kick freely during care routines?

- Own capacity for exploration, interest and curiosity.

So, if repeated often enough, our experiences will influence the way in which the parts of the brain that deal with movement, balance and vision will be reflected in the pattern of wiring that eventually emerges.

This same combination of a similar framework and individual experience also applies to our emotional and thinking world. How our carers react to us in infancy will influence the kind of pathways that are laid down governing how, what, when we feel both about others and, most importantly, ourselves.

As we go through this developmental series, I will keep returning to the links with the brain and experience. For now, let's find out about the structure and pathways in more detail.

Structure

As I have said, we share a great deal of characteristics of our brains with other animals. This is because our brains are the result of thousands, if not millions of years of evolution. In order to help us think about this, researchers have divided our brain into three essential parts:

- First, there is the oldest part - the brain stem, which extends from the back of the brain into the spinal cord. This is often referred to as the 'reptilian brain' and has been largely unchanged by evolution. This structure, fully developed at birth, contains areas that control breathing, temperature, heart rate, sleep functions, stress responses and consciousness.

- Above this there are structures comprising the middle part of the brain, which is often called the mammalian brain because it has almost 'the same chemical systems and structure as in other mammals' (Sunderland, 2006, p19). These structures deal with our emotions and memory and include the gateway for the processing of all our bodily senses (except smell) from both internal and external stimuli.

- At the top of the evolutionary tree comes the cortex, which has six layers and is divided into four lobes - frontal, parietal, temporal and occipital, each of which has special functions.

1. Frontal: appears to deal with the most abstract and complex of brain functions, for example thinking, planning and conceptualising, and the conscious 'appreciation' of emotion

2. Parietal: appears to be mainly involved with movement, orientation, calculation and types of recognition, somatic sensation and body image

3. Temporal: mainly deals with hearing, language, comprehension, sound and some aspects of memory and emotion

4. Occipital: is mostly taken up with visual processing areas.

The cortex comprises the outermost part of the brain. It is its wrinkly surface which gives us the familiar picture we may have of the brain. All the parts of the brain are closely connected, but the oldest parts can be the strongest, especially when we feel unsafe, physically or emotionally.

The cortex contains the structures that appear to be involved in our most rational acts. In particular, an area known as the 'pre-frontal cortex', located at the front of the frontal cortex, is the location of our capacity to reason, plan, think, be aware and have self-awareness. It is here that we seem to depart from the animals, because while dogs, primates, bears or elephants can certainly show emotion and have strong and frequently complex social bonds, it is this awareness of ourselves as persons and our ability to reflect on ourselves (and others) that makes us uniquely human beings.

If you look at a picture of the brain, you will see that it is in two halves and that each half broadly reflects the other, although there are some variations between them in how they function. They are connected by a structure called the corpus callosum, made up of millions of nerve fibres and messages constantly travelling between the two halves. You can think of it as an 'information highway'.

What emerges powerfully from the research is, first, that we do use all the parts of our brain on both sides in varying degrees, depending on tasks. Second, the ability to pull together information depends on this two-way communication, and this function also develops over time as the brain matures.

- There is also the cerebellum. This structure is situated behind the brain stem at the back of the brain. It is very active during movement and in matters of balance and timing. Putting your finger on your nose involves your cerebellum as well as the visual, motor and sensory parts of the cortex.

Pathways

Our bodies are made up of cells and so are our brains. The real magic of the brain is that the cells in the brain 'talk' to each other. These brain cells are called neurons. We have about 100 billion of these, nearly all of them present at birth.

The parts of the cell that receive information are called dendrites and the cell also has an extension or 'tail' called the axon. While there can be lots of dendrites and neurons can have different shapes, they each only have one axon.

Information received enters the cell via the dendrites and then is passed down the axon to its 'end feet', where there are little sacs of chemicals called neurotransmitters. All sensory information is transformed into an electrical impulse and when this reaches the end of the axon, it is the neurotransmitters that carry the message across the tiny space called a synapse to the dendrites of the next axon.

The other types of cells in the brain are called glia. A particular type of glial cell plays a crucial function in that, over time, they produce a fatty sheath called myelin which covers the axon. This allows information to pass along the axon much quicker.

An important thing to remember is that this process of myelination can take many years in different parts of the brain, which is why children can seem to take so long to answer a question or a baby takes some moments to respond when they are in a 'conversation' with you. In fact, the pre-frontal cortex mentioned above is not fully mature until early adulthood.

Growth

Our brains grow and shape in three ways:

- first, the neurons themselves get bigger

- second, the axons get their fatty coats

- finally, the brain grows because of all the connections that are made as we experience our relationships and our environments.

Our brains will grow whatever our experiences are, but it is the type and quality of the experiences that establish what particular pathways are laid down. When sensory information from both outside and inside the body reaches the brain, many connections are made between different groups of neurons. If the experience is repeated often enough, this makes a pattern between those connections that are most used. Other connections, which may have been made in the first place but not used again or very rarely, just wither away.

When a baby is born, lots of information is entering the brain and the baby has to make sense of it. This is where relationships with carers provide babies not only with their emotional experiences but also with familiar routines, allowing these patterns to emerge and the baby to begin to sort out their world.

I mentioned that brain connections not used wither away. If we think back to the example of walking, as a baby gets more confident, all those extra connections made when the baby was just starting out get pruned away to make the pathway the most efficient - like pruning a rose to make it grow more healthily. This also helps to 'shape' the brain, and during the first five years or so of life especially there are millions of connections being formed, pruned and then reformed to make room for the thousands of new experiences that build on those earlier pathways. This 'pruning' continues throughout life, but not as rapidly or dramatically as in these earliest years.

Skills and abilities

Are there links with the brain's growth, and emerging skills and abilities? In general, yes, as brain surges appear to broadly coincide with changes in skills and abilities - at around eight to 12 months, two to three years, five to seven years and ten to 13 years, and probably throughout adolescence.

Gender

Does whether we are male or female have an effect on the workings of the brain? Yes - but in very subtle ways. The area in which there is most agreement is in that of verbal and visual-spatial skills, with females and males showing different tendencies. For example, women's general use of language, fluency, and grammar, together with manual precision and arithmetic calculation, appears to be more proficient.

Males appear to perform better at tasks that are spatial in nature, and also in mathematical reasoning and in finding their way through a route. They are are more accurate in throwing and catching. However, there is enough research around to make us to think seriously about different approaches to ways of learning.

The brain is fascinating and wonderful. It needs our care, respect and acknowledgement that it is the source of who we are.

Child Development part 3 will be published on 24 January

FURTHER READING

Balog, D (ed) (2006) The Dana Source Book of Brain Science, 4th edition. Washington, Dana Press (www.dana.org)

Baron-Cohen, S (2003) The Essential Difference: The truth about the male and female brain. New York, Basic Books

Blakemore, SJ, Frith, U (2005) The Learning Brain. Oxford, Blackwell

Frith, C (2007) Making up the Mind: How the brain creates our mental world. Oxford, Blackwell

Gerhardt, S (2005) Why Love Matters. Hove, Routledge

Rizzolatti, G, Fadiga, L, Fogassi, L, Gallese, V (2002) 'From Mirror Neurons to Imitation: facts and speculation', in Metlzoff, A, Prinz, W (eds) The Imitative Mind, pp42-62. Cambridge, Cambridge University Press

Robinson, M (2007) Child Development Birth to Eight: A journey through the early years. Open University Press

Sax, L (2001) 'Reclaiming Kindergarten: Making kindergarten less harmful to boys', in Psychology of Men and Masculinity, vol2, no1, pp 3-12

Sunderland, M (2006) The Science of Parenting. London, Dorling Kindersley

Smith, A (2005) The Brain's Behind It. Norwalk, Connecticut, Crown House

WE HAVE 'MIRRORS' IN THE BRAIN

The accidental discovery in primates of 'mirror neurons' was a breakthrough in establishing whether there was a 'brain basis' for imitation. These particular cells 'fired' when the monkey watched a person or another monkey picking up a peanut, for example. Similar mirror neurons have been found in the human cortex, which respond to vision, the senses and movement. So when we watch someone picking up a cup, our brains fire up too.