That Neuroscience Guy - Neuroscience Bite - Apraxia

Episode Date: July 1, 2022

Apraxia is a neural disorder that causes serious deficits in various motor functions. In today's Neuroscience Bite, we discuss the neuroscience behind Apraxia. 

Hi, my name is Olof Kreg Olsson and I'm a neuroscientist at the University of Victoria. And in my spare time, I'm that neuroscience guy. Welcome to another neuroscience bite. So I was chatting with a colleague here in New Zealand about apraxia and I realized that we hadn't talked about apraxia on the podcast. So I thought I'd just use it as a quick bite to tell you about a neural condition that has some interesting behavioral consequences. There are two principal forms of apraxia. There's ideational apraxia and ideomotor apraxia. And both of them are typically associated with damage to the parietal cortex

and a specific part of the parietal cortex called the inferior parietal lobule. It appears this is a part of the brain that allows us to work with tools. By tools, I mean literally tools like a hammer or a saw, but also things like a comb or a toothbrush. So with ideational apraxia, it's pretty interesting because a person, if you, for example, showed them a comb, they would know what a comb is. They'd say that's a comb, but they've lost all their memories of what to use that particular tool for. So basically people with ideational apraxia, because of the neural damage that they've suffered, they've lost the concept of the movement. So they know it's a comb but they literally don't know what to use it for and they can't use a comb anymore or other tools.

Typically with apraxia, it's not a specific item but it's a whole range of tools that people just use or lose the ability to work with. But remember, it's only tool use. So they can reach out and touch things, for instance, because they still have control of their limbs. They've just lost this weird ability to interact with tools. And that's ideational apraxia. They don't know how to do that anymore. With ideomotor apraxia, it's a little bit more specific and even a bit more quirky. People with idiomotor apraxia, it's a little bit more specific and even a bit more quirky. People with idiomotor apraxia, for instance, if you gave them a comb and said, well, pretend to brush your hair, they would basically move the comb over the top of

their head and it would look like they were combing their hair. However, if you remove the comb and you say, well, just pretend your finger's a comb, alright, so you can imagine holding out your index finger, pantomime or act out using a comb. And people with ideomotor apraxia, they can't do this. So if you don't have ideomotor apraxia, you would have your index finger and you would move it across the top of your head like you're brushing your hair. But people with ideomotor apraxia have lost that ability. They can't do that. But remember, if you give them a comb, they can brush away. So it's like they're losing their ability to

visualize the tool, if you will. So they can't visualize what you do with the tool, but as soon as you give them the tool, there's enough memory there that allows them to do the appropriate action. So that's a quick neuroscience bite about apraxia. It's an interesting neural disorder, obviously horrible if you have it. It's associated with damage to the parietal cortex and specifically the inferior parietal lobule. My name's Olive Kregolson, and I'm that neuroscience guy. Thanks for listening to another Neuroscience Byte. Please subscribe to the podcast, send us ideas by following me on Twitter, at that neuroscience guy, and of course,

check out our website for our Etsy store and for our links to Patreon, where you can support the podcast. Thanks so much for listening, and I'll see you on Sunday for another episode of the podcast.