Everyone has experienced the gripping fear of being lost. Whether it is accidentally wandering too far from Mom in a department store or making a wrong turn down a dead-end street, getting lost is a normal part of life. We make mistakes, can’t find our way for a few moments, but we always end up making our way back to safety soon enough. For some people, though, that feeling of being lost is not a rare event, but a daily occurrence. For those suffering from Developmental Topographical Disorientation (DTD), not knowing where they are is as normal as breathing.
![Path integration navigation is what allows you to get up in middle of the night and get a glass of water while you are barely conscious. [Graphic by Staff Illustrator]](http://www.curiousyoungwriters.org/wp-content/uploads/2014/06/path-navigation.png)
Path integration navigation is what allows you to get up in middle of the night and get a glass of water while you are barely conscious.
[Graphic by Staff Illustrator]
But what exactly is DTD? To answer this question, we first need to determine exactly how people remember directions and locations. Navigation can be grouped into two categories: landmark orientation and path integration (Iaria, 2011). Landmark orientation takes geographic and manmade features and turns them into signs telling you when to turn or move straight ahead. For example, you might know that your friend’s street is the second left after the bakery. In this case, the bakery is a landmark which helps you decide where to go. Path integration relies more on memorization of how many turns a person needs to make or how far they need to move. This type of navigation is what allows you to get up in middle of the night and get a glass of water without banging into walls or tripping over furniture. Your brain automatically remembers how many turns to make to get out of your room or steps to take down the hall, so even in your sleepy state, you can find your way.
Luckily for you, your brain seamlessly combines both landmark orientation and path integration so you can move about without thinking too much. Unfortunately, for some people the brain simply can’t retain all this information. Neuroscientist Giuseppe Iaria of the University of Calgary, the man who discovered DTD, explains that patients with DTD can’t form “cognitive maps,” meaning they cannot mentally visualize their surroundings, and so never form memories of their locations (Siddique, 2013).
![Place cells located in the hippocampus of the brain help form mental maps of your location. [Photo: Hippocampus from Anatomography, Life Science Databases, License: CC BY-SA 2.1 JP]](http://www.curiousyoungwriters.org/wp-content/uploads/2014/06/hippocampus.png)
Place cells located in the hippocampus of the brain help form mental maps of your location.
[Photo: Hippocampus from Anatomography, Life Science Databases, License: CC BY-SA 2.1 JP]
Neuroscientists Dr. Nachum Ulanovsky and his student, Dr. Michael Yartsev, of the Weizmann Institute were not satisfied. They realized that rat models only dealt with movement in a two-dimensional space, yet, humans do much more than run in straight lines; they move in a three-dimensional space.
In order to update the model for spatial navigation, scientists are beginning to study the brains of our furry mammalian friends: bats. Bats move three dimensions: right or left, forward or back, and also up or down. Bats are best known for their ability to navigate using a series of sound waves, also known as echolocation.
![Bats are famous for their ability to navigate using sound waves, also known as echolocation. [Edited Photo: Bats by ASU - Ask a Biologist, License: CC BY-SA 3.0]](http://www.curiousyoungwriters.org/wp-content/uploads/2014/06/echolocation.png)
Bats are famous for their ability to navigate using sound waves, also known as echolocation.
[Edited Photo: Bats by ASU – Ask a Biologist, License: CC BY-SA 3.0]
![Big brown bats, such as these, are helping scientists learn more about spatial memory and DTD. [Photo: "Big Brown Bat (Eptesicus fuscus), in Flight at Night, Rogue River National Forest, Oregon" by Angell Williams, License: CC BY 2.0]](http://www.curiousyoungwriters.org/wp-content/uploads/2014/06/bat.png)
Big brown bats, such as these, are helping scientists learn more about spatial memory and DTD.
[Photo: “Big Brown Bat (Eptesicus fuscus), in Flight at Night, Rogue River National Forest, Oregon” by Angell Williams, License: CC BY 2.0]
In Brief:
- Developmental Topographic Disorientation (DTD) is a mental condition with no known cause or cure that stops people from forming mental maps of their surroundings.
- People with DTD are unable to remember how to move to and from places, even those as familiar as their own homes.
- Recent studies involving bats’ ability to form long-term spatial memories of specific environments offer a new way to learn more about the causes of DTD.
This article was written by cYw22. As always, before leaving a response to this article please view our Rules of Conduct. Thanks! -cYw Editorial Staff
June 6, 2014
Fascinating article – thank you! I’m always lost – this helps to explain why. Kathleen
June 15, 2014
I’m glad you enjoyed it! I get lost extremely easily too (one of my earliest memories is of being lost in a department store!) so it was really interesting to learn more about how our brain deals with directions and navigation.
June 6, 2014
fascinating article – and very clearly put – thank you! As a person who is always lost in space, this gives me at least a possible reason why – DTD.
June 15, 2014
Thank you so much for reading! I can definitely relate on constantly being lost – I always seem to “zone out” only to look up and realize I have no idea where I am! Hopefully, as researchers learn more about DTD and the way our brains navigate, we can find ways to gain a better sense of direction.
June 6, 2014
Dear Cyw22,
Thank you for the article drawing attention to a condition that is little known. Most important, you make us ponder, and appreciate, the many activities the brain coordinates every day without our having to think them through. I applaud you for highlighting the exploration of brain function through animal models.
June 15, 2014
Thank you so much for your kind comment! I’m so glad I got to share some of my newfound knowledge about this rather unknown condition! To be honest, before I first started researching, I had never even heard of DTD, so it was a very enjoyable and educating experience to learn more about the condition and about our brain in general. I definitely don’t take the many functions our brain intuitively fulfills for granted anymore! In general, the whole experience of researching and writing has made me extremely excited about the future of neurology and all the incredible discoveries there are still to make.
June 9, 2014
Much as I am terrified of bats, I was fascinated by what we can learn from these amazing creatures. And I certainly applaud their finely honed senses of direction, a gift I am not blessed with. As always, I find these cYw articles informative, easy to digest and always leaving me with a thirst for more knowledge.
June 15, 2014
Bats are certainly not the fuzziest or most cuddle of creatures! Still, I can’t help but admire their amazing echolocation and all the knowledge they have given us. Thank you for reading and for your kind comment; it’s very excited to share my findings on these incredible animals!
June 16, 2014
Great article, I have just one comment.
The bats in the picture at the top of the article are little red flying foxes (Pteropus scapulatus), which, unlike the big brown bats in Barchi et al. study, do not use echolocation to navigate. Fruit bats, or flying foxes, use sight and smell to locate their food–fruit, nectar, and pollen.
June 16, 2014
Thanks for your insight, I didn’t realize that before! I suppose it just goes to show that there is an extraordinarily amount of diversity, even among similar creatures, in modes of survival. Strangely enough, though, it seems that navigation sparks a common thread between certain fruit bats (namely the Egyptian fruit bat) and other insect-eating ones. Dr. Ulanovsky and Dr. Yartsev of the Weizmann Institute (mentioned briefly within the article) experimented with Egyptian fruit bats, only to realize that they rely on “place cells” to form mental maps of their surroundings in the same way that big brown bats do. However, it’s important to note that this specific species does use echolocation, unlike the majority of fruit bats, as you mentioned. It would be fascinating, though, to see how non-echolocation-using bats deal with navigation and whether that matches the methods of their echolocation-using cousins.
September 4, 2014
Numerous reports by owners of blind dogs indicated that their dogs were mapping based on sounds and echoes, plus scents. // thanks for a near report.