The Brain

Welcome to your brain! On your run today, you'll see how the brain works, from core functions common to many animals, to unique elements of the human brain. Over 10K, you'll travel the 500,000 miles of connections between the neurons and cells that make up your brain, and through millions of years of evolutionary history. As you start running, take notice of your heart rate rising, and your breathing speeding up, and we'll see how these critical functions are managed.

The brainstem is right at the base of the brain, connected to the spinal cord. This controls functions that take place without conscious thought, such as heart rate and breathing. It acts as a signal exchange, and monitors cardiovascular function to regulate heart rate and blood pressure.

The cerebellum is located behind the brainstem and draws in information to coordinate your voluntary movements, such as running! It also helps set your posture, and maintains your balance.

Your eyes send information as electrical signals to the occipital lobe, but also to regions of the brain that deal with memories and actions. That means that if something suddenly runs in front of you, you can take evasive action before you even recognise you've seen it!

Your ears turns the noise vibrations they pick up into electrical signals, which are sent to the auditory cortex. The auditory cortex acts as a filter, splitting background noise from the sounds that are important for you to pay attention to. Your brain is particularly attuned to picking up voices.

The auditory cortex is the first of a series of sorting houses for noise. The signals go on to a part of the brain stem called the cochlear nuclei. It decides where to send noise information based on duration, loudness, frequency, etc. Your brain uses this to work out if you're in danger.

Managing emotions is a big job! There are three bits of the brain responsible for emotional responses. The amygdala handles fear, working out what you need to respond to urgently. In a split second, it can make a decision and trigger chemicals such as adrenaline, to get your body ready to run.

Your "gut feeling" is handled by the insula. It takes information from your senses and combines it with other information, such as past experience, to decide how to react. It's linked to emotions like love, pain, and enjoyment, as well as the feeling of consciousness, and social emotions that help you assess facial expressions. The third area is the periaqueductal gray, or PAG for short. The PAG controls your heart rate in response to emotional stimuli, is your risk assessor, and is where feelings such as anxiety and fear begin.

Short-term memories are are stored in the prefrontal cortex, and allows you to retain a small amount of readily accessible information. It might store words on a sign you just saw. Important short-term memories can be moved into long-term memory . The hippocampus acts as a waiting room for memories being moved to long-term memory. When your memories are stored, your brain changes itself by altering nerve cells, and strengthening connections between nerves. The more you use a memory, the easier it is to find it when you need it.

Understanding language involves many parts of the brain working together, including parts that deal with memory and emotion. Broca's area is in the frontal lobe and is split into two sections. The front part is responsible for understanding the meanings of words (semantics). The back part is responsible for understanding how words sound (phonology). It's connected to Wernicke's area, which is responsible for decoding written and spoken language.

You can stop running now and have a drink. While running, you've lost water through sweat and in your breath. When you lose water, your brain gets signals from your organs, and the hypothalamus sends out a "drink now" message. Your brain is 70% water, and even mild dehydration can impact your mood, sleep, and general health. So be kind to your brain, and take a drink next time you set out for a run!