What does each part of the brain do?

05 July 2016


Researchers use functional magnetic resonance imaging (fMRI) to reveal brain activity during emotional situations. Image credit: Inge Volman et al.



What does each part of the brain hemisphere do to help us live?


Kat Arney put this to neuroscientist Laura Ford, from the University of Cambridge...

Laura - Goodness me! This is a huge question.

Kat - It's basically like, all of neuroscience right?

Laura - Yeah. I can do that in 3 or 4 minutes? Easy! So, maybe I should just take you through a bit of a whistle stop tour of the brain. If we start, we have our brain stem and that takes care of things that we don't think about.

Kat - So that's the bit at the back of my neck.

Laura - Exactly. The bit where you can feel it.

Kat - Let's do this at home. Feel the back of your neck.

Laura - Let's take you through it. so everyone, feel the very bit where you can feel it's a little bit bony, a little bit protruding, and that's where you have your brain stem. And that's where it controls things like swallowing and breathing, and all the things that we don't think about.

Kat - This is the really old bit, isn't it? this is like the ancient brain.

Laura - It absolutely is and for a very good reason, otherwise, we wouldn't be able to breathe or function. On the back of there, there's also something that you can't feel unfortunately but if we move our just hand a little bit further up, we're on the cerebellum. The cerebellum is well-known to most people on the weekend because it's the part that controls our movement and our gait. It's the bit that alcohol allows us to be a little bit woozy. And so we can't walk straight.

Kat - Or controls our dancing to put it a little more positively

Laura - Blame it on the cerebellum, absolutely. And then we have the cerebrum which is really where we're coming up into the hemispheres.

Kat - So this is the top like the big bits at the front of the brain, the big stuff, the grey matter.

Laura - Absolutely. So this is when you ever see a picture of the brain and you see it kind of look all folded. So those are called the sulci and the gyri. The reason that they're like that is because you need more surface area to fit in the hundred billion of neurons that we have that allow us to talk, walk, and for you to listen to me now. If you pop your hand on the back of your head again, you've got it resting over the occipital lobe. This is where the visual processing is done, so we're looking.

Kat - So, seeing at the back of the head.

Laura - Absolutely, light, movement, colour, so on and so forth. And then carrying on moving forwards, as if we're going to come to the front of our forehead but stop before we get there.

Kat - This is where our headphones are resting.

Laura - Absolutely, so you've got them at home. And then we're at the parietal lobe which is kind of responsible for visuospatial information and sensory integration because our sensory cortex sits in there.

Kat - So, it's putting everything together from the world around.

Laura - Absolutely. So when we were talking earlier about feeling on our bottom the seat, things like that. And then if we carry on walking forward, we have the frontal lobes. This, as I mentioned earlier is relating to our personality, our executive planning skills, our working memory, so on and so forth. And then we also have, if you're going to decide you don't want to listen to me anymore, so you wanted to put your hands over your ears, you'd be very close to the temporal lobe. The temporal lobe is responsible for hearing as you would imagine and also, for memory functions. So that's kind of a very quick tour but if we think about how the hemispheres may differ because what we're increasingly finding is the brain is very networked and it utilises both hemispheres for many of the functions that we carry out. But there is some form of lateralisation in some of the things that we do.

Kat - Because I think I covered this recently. We did the myth busting on, are you left brain or right brain? But there are some things that are left and right out there.

Laura - Absolutely, yes. So mainly, and the one that most of you will have heard of is language lateralisation. And that, in most right-handed people is taking place within the left hemisphere. Very interestingly, there is a subset of left-handed people that it will actually be right hemisphere localised. Not all, but some and a fewer still in some people that there's bilateral organisations, that's very interesting. In terms of the right hemisphere, we find from looking at brain injury, most notably, this hemispatial neglect which is really interesting, where you can still see things in one side of the visual space but you just lose your ability to attend to it. and that seems to be more long lasting if you have damaged your right hemisphere than your left. Meaning that it's likely to be more important in visuospatial processing.

Kat - So I think basically, the summary is, all bits of our brain are really important and they're all used. But there are sort of different areas that are special.

Laura - Yes.


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