• Question: When you concentrate really hard how much electricity is being used/created in your brain

    Asked by anon-285569 on 3 Mar 2021.
    • Photo: David McGonigle

      David McGonigle answered on 3 Mar 2021:

      Hi Angel! Eek – hard question: I have a feeling I’m going to need a lot of energy to answer it…
      But – bad jokes aside – I like to use the term *energy* when thinking about how hard the brain works. You’re right that brains use ‘electricity’ – it’s just not the exact kind of electricity that you’d find in the wiring of your house, for example. Brain cells – neurons – are part of the family of cells in the body that use ‘bioelectricity’ to communicate. The thing is, though, they’re not all wired directly to each other – there’s a tiny gap, roughly the size of a bacteria, separating each one. It’s not a perfect comparison, but neurons are a bit like little batteries: they each store a tiny amount of charge. When this charge changes, they release chemicals called ‘neurotransmitters’ that cross the gap to the next neuron in the chain, and – most of the time – they signal the message onwards.
      Phew! Biology bit over – so what does this have to do with your question?
      Well, batteries run down, right? Well, not if you have rechargeables: they need some kind of energy to recharge them to use again. It’s not so different in the brain: every time your brain cells talk to one another, they need to recharge and get ready for the next time, which burns off energy from your body. Now, the brain is an *incredibly* hungry bit of your body – it takes up only 2% or so of your weight but uses 20-25% of the *total* energy. And you’re right: when you’re concentrating, you do use more energy, because the neurons need that to work. But it’s only a tiny bit more than the large amount that the brain’s already using just to, well, be your brain, so for a final answer: not much, really (!). Thanks for a great question!

    • Photo: Dennis Relojo-Howell

      Dennis Relojo-Howell answered on 3 Mar 2021:

      Whoa! What a question. That feels like a question from University Challenge. LOL. I did a bit of reading and here’s two interesting factoids I came across:

      • It’s estimated that our brain spends around 20% of our total energy requirements – that’s around 400 to 500 calories a day.
      • According to Kwabena Boahen, a computer scientist at Stanford University, a robot with a processor as smart as the human brain would require at least 10 megawatts to operate.

      With a question like that, I feel that you’d be good at neuropsychology! Keep it up.

    • Photo: anon

      anon answered on 4 Mar 2021: last edited 4 Mar 2021 7:28 am

      Hi Angel,
      The two scientists above have explained this really well!
      I wanted to add a bit of a different comment – what the brain does when it’s not concentrating (but still using lots of electricity!) – this is called the ‘default mode network’. Most people believe that when we think hard that the brain uses up a lot of power, but actually, it uses up just as much, but in different ways when we are doing and thinking about absolutely nothing! So things like daydreaming or mind-wandering are great examples here. It has been suggested that this electrical activity in the brain is actually the basis of consciousness, essentially who we are as individuals and the basis of how we think.

      This can be measured by scanning the brain in something called an ‘fMRI machine’. This is a way of looking at the brain in ‘real time’ as the person is thinking or in this case not thinking. It measures the level of neuron activity (which David has given a great description of) and has found that some areas light up more than others and in different ways when comparing concentrating to daydreaming.

    • Photo: Alex Baxendale

      Alex Baxendale answered on 4 Mar 2021:

      This is a really great question! And it’s a little hard to explain all at once so I can break it down for you! Electricity is simply the movement of particles from one place to another, negatively charged particles will push away positively, and positively charged will push away negatively (like a magnet!), our brain does this with specific chemicals to create very tiny charges, in fact we measure it using Microvolts (1 volt is about 1,000,000 microvolts). It was mentioned by Lara that we use a method called the ‘default mode network’ which is our brain doing ‘background stuff’ when we aren’t concentrating (definitely check out her more detailed description!), so we don’t actually use more energy or electricity when thinking hard – the default mode network does stuff all over the place, and concentrating hard stops the default mode network and pushes all of the activity to a specific place where we concentrate – but it is still the same amount of effort! Some scientists think that our brains run on around 20 watts of energy (standard lightbulbs use 40 – 60 watts!)

    • Photo: Christina Brown

      Christina Brown answered on 4 Mar 2021:

      Hi Angel,

      Everyone else has answered your question thoroughly so I won’t repeat what they’ve said here. I just wanted to elaborate on how we can apply experimental techniques to show what brain areas are more active in a particular task in animals. This is similar to the fMRI technique we use in humans, but instead we can see what specific brain cells are active during learning.
      When brain cells are activated (producing bioelelectricity), they express a protein that prepares the cell for being activated again. You can use a technique that adds a colour marker on the protein so you can see what cell is activated during a specific task. For example this could be a mouse getting a reward when it hears a bell. We can then pinpoint where the most of these activated cells are to observe what brain area is most important and most active during this task. This has helped us discover what brain areas are most important in storing memories.

    • Photo: anon

      anon answered on 4 Mar 2021: last edited 4 Mar 2021 2:29 pm

      Hi Angel,

      This is a really good question! I don’t specialise in neuropsychology (this is the part of psychology which focuses on how the brain and the nervous system control how people think and behave), so I am definitely not an expert on this topic so I will let the others handle the specific details of this! I do know that the brain uses around 20watts of energy to function, which is actually really low – the average lightbulb takes about 60watts to light up! The brain uses glucose as fuel, which it gets from the food you eat.

      Thanks for your question!

    • Photo: Lisa Orchard

      Lisa Orchard answered on 4 Mar 2021:

      A great question! This is not in my area so I will leave the answer to the professionals above. 😀

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