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Aitor Zandueta
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Cephalopod Pupils

Octopus and other cephalopods seem to use colour, including in some cases to match their skin colour and pattern to their backgrounds, and yet they only have a single-type of monochromatic photoreceptor in their retina. Other animals, like us, perceive colour thanks to photoreceptors tuned to different frequency ranges of light. In the past researchers have proposed that mechanisms in the skin of cephalopods may detect colours, but only one type of opsin has been found in the skin, even via the recent octopus genetic sequencing effort, nor has a method of filtering that single known opsin response been found.

UC Berkeley graduate student Alexander Stubbs and others believe that they have a possible answer; the strange dumbbell, u- and w-shaped pupils of cephalopods may be used to allow light to reach multiple areas of the retina simultaneously, to create a blurred image with chromatic aberration or colour fringes which can be interpreted by the cephalopod to perceive colour at the expense of sharpness.

“We propose that these creatures might exploit a ubiquitous source of image degradation in animal eyes, turning a bug into a feature,” Stubbs said. “While most organisms evolve ways to minimize this effect, the U-shaped pupils of octopus and their squid and cuttlefish relatives actually maximize this imperfection in their visual system while minimizing other sources of image error, blurring their view of the world but in a color-dependent way and opening the possibility for them to obtain color information.”

More here (press release): https://goo.gl/KklcYo

Video (YT ~4 mins.): https://goo.gl/7QeiyC

[...]
As a specific example, we constructed a computer model of the visual system of cephalopods (octopus, squid, and cuttlefish) that have a single unfiltered photoreceptor type. We compute a quantitative image quality budget for this visual system and show how chromatic blurring dominates the visual acuity in these animals in shallow water. We quantitatively show, through numerical simulations, how chromatic aberration can be exploited to obtain spectral information, especially through nonaxial pupils that are characteristic of coleoid cephalopods.
[...]

More here (paper open): https://goo.gl/gNV60Z

Image: https://goo.gl/OsFAFP
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I just love this ->
This collection just surpassed 20,000 followers! That's a lot of science and approximately 0.44% of the followers Neil deGrasse Tyson has on Twitter!

I'd like to personally apologize to Google for the bandwidth required to serve up all these GIFs. By my estimates, the last post required 182.9GB of bandwidth!

#ScienceGIF   #Science #GIF 
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#spiderman  

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Best Metroid fan film E-V-E-R

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Xenomorph cuteness

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Compressorhead, the future of heavy music

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Back to the Future IV esklusiban etorkizunetik ekarria

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All the ships from Battlestar Galactica (and some more)

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I just got this message. What do I click? #ttip  
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