SCIENCE
OF MIND AND MATTER
Tom Anderson (Year 10) explains how our little grey cells make a big impact
‘In most areas of science, there are long periods of beginning before we make real progress’ Eric Kandel
T he brain is the most complex organ in the human body, producing every thought, feeling, action, memory and experience we have of the world. We all have this jelly-like mass: weighing in at 1.4kg, it keeps our body functioning and our thoughts flowing. It’s powered by 100bn neurons; each one makes contact with tens of thousands of others via tiny structures called synapses. These connections are constantly changing: a million new connections are forged every second of your life. This constant flux is what makes each brain unique: it is in these connections that memories are stored, habits learned and personalities created. So how exactly does our brain work? If you have ever seen a photograph of a brain, you will notice its light grey colour; this is because it is composed of grey matter and white matter. The grey matter is the cell body of the neurons; the white matter is the network of thread-like tendrils, called dendrites and axons, which connect neurons to other neurons. Around the axons, lipid myelin forms a thin layer – the ‘myelin sheath’ – in order to provide electrical insulation. These are white in colour – hence, ‘white matter’. But why does this matter matter? The role of grey matter is vital: it processes sensory and motor information and controls emotions, memory and intellect. White matter, meanwhile, is the major component of the central portion of the cerebral part of the brain; it nourishes and insulates the nerve fibres in the brain. Brain structure is partly shaped by genes – but largely formed by experience. It was recently discovered that new brain cells are being born throughout our lives in a process known as neurogenesis. The brain, we think, undergoes bursts of growth and then periods of consolidation, when excess connections are pruned. The three main ‘bursts’ come in the first two or three years of life, puberty and young adulthood. What these ‘bursts’ do has yet to be clearly determined. Some evidence suggests that the process is key to functions such as learning and memory. New neurons increase memory capacity and reduce the overlap between different memories: the ‘bursts’, therefore, help to enhance these processes, and that is why during early life, our memories are more vivid – though this is also due in part to our older selves having more memories with which to deal and no ‘bursts’ to help deal with them. There are different parts of the brain, each with their own specific function. The most obvious anatomical feature of our brain is the undulating surface of the
Brain structure is partly shaped by genes - but largely formed by experience
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