ANATOMY OF THE BRAIN

OUR BRAINS HAVE THREE MAIN SECTIONS: THE CEREBRUM, CEREBELLUM AND BRAINSTEM THE cerebrum is formed by two hemispheres, each of which has four lobes. Although we now know that most brain functions rely on many different regions across the entire brain working in conjunction, it is still true that each lobe carries out the bulk of certain functions:

attention, planning, making decisions

touch, proprioception (e.g. being able to touch your nose with your eyes closed) hearing, feeling emotions, forming memories vision

The part of the brain that you can see from the outside is called the cortex. The wrinkles in this structure are evolution’s way of fitting as much cortex as possible into our skulls. In fact, the amount of folding has increased throughout mammalian evolution: mice, for example, have no folds, whereas dolphin and human brains are full of them. Each bump is called a gyrus, and each wrinkle a sulcus.

A lot of other brain structures lie beneath the cortex. Our memories about our lives are formed by the hippocampus, a seahorse-shaped brain region in the temporal lobe. Another temporal lobe structure is the amygdala, which is needed to process emotions. Connecting the two brain hemispheres is the corpus callosum, a highway for communication between the left and right sides of the brain. The cerebellum (“little cerebrum”) sits at the rear base of the brain and is important for coordinating and controlling our movements. Intriguingly, more than half of all neurons in the human brain are in the cerebellum, even though it makes up less than 10 per cent of our entire brain volume. The brainstem is, in evolutionary terms, an ancient part of the brain. Vital functions such as breathing and heart function are controlled by the brainstem, as is our sleeping cycle. Because of this, damage to the brainstem can be life-threatening.