Don’t Judge a Brain by its Size

Jumping spider (Phidippus audax)
Jumping spider (Phidippus audax)
Device used to inject electrode into spiders' brains
Device used to inject electrode into spiders’ brains

According to Ronald Hoy, a professor of neurobiology and behavior at Cornell University, jumping spiders are one of the smartest invertebrates, despite having a brain the size of a poppy-seed (less than a millimeter in diameter). Instead of making a sticky web to catch their prey, jumping spiders find their victims, stalk them and then jump on them. What enables jumping spiders to have such precise hunting behaviors? Jumping spiders have a unique visual system which collects information from 2 large eyes which specialize in high-resolution vision, and 6 smaller eyes which detect motion. This visual system essentially gives them a 360-degree view of their surroundings. However, little is known about the neural mechanisms behind the visual brain areas of jumping spiders. This lack of information has stemmed from the fact that, until recently, there was no way to insert an electrode into a spider’s brain without causing inner fluids to squirt out, which ultimately kills the spider.

A group of Cornell University researchers (G. Menda., et. al., 2014) developed a way to gain access to jumping spiders’ nervous system without causing catastrophic fluid loss. This technique has allowed us to gain a better understanding of the neural basis behind jumping spiders’ special visual network. The researchers took recordings of the spiders’ brains while they watched videos of naturalistic things like prey and other spiders. They discovered a neuron that seemed to  “integrat[e] the information from the spider’s two independent set of eyes, a computation that might be expected to involve a network of brain cells” (Gorman). Prey-like objects, such as flies, caused bursts of excitation from single cells. Although jumping spiders have only a fraction of the number of neurons of mammalian brains, they behave much more like mammals than spiders. Even though their brains are minuscule, their visual brain areas allow them to take part in precise hunting behaviors.

 

Work Cited:
G. Menda., et. al., (2014). Visual perception in the brain of a jumping spider. Current Biology, 24, 2580-2585.

Gorman, James. “Unexpected Complexity in a Spider’s Tiny Brain.” The New York Times. The New York Times, 03 Nov. 2014. Web. 10 Apr. 2015. <http://www.nytimes.com/2014/11/04/science/mapping-the-tiny-brain-of-the-aristocrat-of-arachnids.html&gt;.

S. Heinze, (2014). Neurobiology: Jumping spiders getting on board. Current Biology, 24, R1042-R1044.

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4 thoughts on “Don’t Judge a Brain by its Size

  1. This article was quite interesting to read! The information that is presented is completely new to me but I feel like the author explained the current research very thoroughly. It is exciting to learn that current research has found a way to access the neural brain system of jumping spiders without causing death. This new developing research allows us to get a great visual understanding of the neural basis behind their visual network.

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  2. This definitely puts the saying “the bigger, the better” out of business. It is really interesting to think about something that small being able to function on a heightened neurological level. The 360 view is also an awesome concept. Wouldn’t that just make life a whole lot easier. Also the fact that we can analyze a brain that is the size of a poppy seed is incredible! That just shows how far science has come and the potential to understand even more fascinating information about brains in the future.

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  3. What an interesting invertebrate to study! The new technology that we are discovering will most likely reveal even more amazing skills of these tiny insects and bugs. Before we could only observe and make an educated guess on why animals were capable of certain behaviors. This article shows that we can step pass those boundaries and get inside the smallest of brains. With this new knowledge I’m sure we will only discover more about the jumping spider and many other small invertebrates. Hopefully, we will even discover a small amount about our own brain as we discover information about more and more animals.

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  4. Wow, more reasons to be afraid of spiders then!! I wonder how they use the integrated visual information to produce the quite elegant motor responses they perform. Maybe mammalian brains are just highly inefficient in computation, thus require a much larger volume. If that’s the case, we can copy the neural networks in jumping spiders to produce even more elegant artificial intelligence algorithms. Just maybe.

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