This week; we hear about octopodes having temper tantrums when exposed to HDTV, explore why some people are genetically wired to feel more pain and how eyeless scorpions are not stuck down an evolutionary blind alley. Plus, how scientists can use a brain scanner to see what you're imagining in your mind's eye!
In this episode
00:15 - Octopus mood swings revealed in high definition
Octopus mood swings revealed in high definition
Pushing a high definition TV screen up to the side of an octopus's aquarium tank and showing them images of crabs and other octopuses, scientists have revealed these intelligent marine creatures can undergo major mood swings ranging from glum to excitable and aggressive.
Previous attempts to show moving pictures to octopuses have failed, probably because the old style cathode ray TV screens only show pictures 26 times a second, which isn't fast enough for their sophisticated eyes so the images were probably unrealistic and incomprehensible to them.
Renata Pronk and colleagues from Macquarie University, Australia decided to try octopuses on the new generation of liquid crystal high definition TV screens and with a bit of trial and error they discovered that octopuses do respond to image shown at a rate of 50 frames a second.
They were working a species that lives in Sydney harbour called, Octopus tetricus, and known as the Gloomy Octopus. The team knew the octopuses could see the HD images when they rushed up and tried to attack pictures of a crab - their favourite food.Show them film of another octopus and they dash to the back of the aquarium and try and hide.
Publishing in the Journal of Experimental Biology, the team repeated their tests over the course of several weeks and uncovered the octopuses' mood swings.
In the same day, an individual octopus reacted in a consistent way to film of a crab or another octopus. But later the same week, their behaviour was often very different. Some animals were initially quite excitable, but on another occasion were gloomy and much less enthusiastic.
The team also tested the octopuses' curiosity, showing them film of a jar they hadn't seen before. Some days they weren't bothered by it, and other days they would be curious and go take a look.
While it seems that octopus may have personalities, they aren't especially consistent over time. Get them on a bad day and an octopus can be very grumpy, but try again tomorrow and you might find a very different animal indeed.
Now that Pronk and the team have worked out how to play octopus movies they are keen to find out more about these extraordinary, intelligent animals including how they communicate with each other.
03:54 - Pain perception under genetic influence
Pain perception under genetic influence
Cambridge researchers have identified gene sequences that make some people feel more pain.
Molecular biologist Geoff Woods, together with colleagues internationally, 
made the discovery when he compared the pain scores reported by 578 arthritis patients with the severity of their disease as revealed as revealed by X-rays of their joints.
Some patients, the team found, were reporting more pain than others, despite having arthritis of similar severity.
To find out why the researchers then matched up the patients' pain scores with the DNA sequences they carried for a gene called SCN9A, which is known to be active in pain-conveying nerve fibres.
This led the team to identify two variants of the gene in the patients, a rarer "A" form and a more common "G" form. On average, patients carrying the A variant tended to report more severe pain than patients carrying the G form of the gene, despite having arthritis of similar severity.
To confirm the findings, the researchers then repeated the study on 179 patients with lumbar back pain, with similar results, and also subjected a group of female volunteers to a range of painful stimuli, again demonstrating that individuals carrying the A form of the gene were more pain-sensitive.
To find out why, the researchers expressed the SCN9A gene in cultured HEK293 cells, which have nerve-like properties. The gene encodes part of an ion channel, which sits on the membrane and allows sodium to enter the cell, altering its electrical activity.
In these cells, the team found, the A and G forms of the gene had subtly different electrical properties, sufficient to explain the increased sensitivity of carriers of the A form to painful stimuli.
This shows, say the researchers in their paper in PNAS, that human pain perception is under genetic influence; understanding how to modify the functions of these pain-specific genes will inevitably lead to improved analgesics and the identification of individuals with more specific pain-killing requirements.
07:20 - Eyeless scorpion isn't stuck down a blind alley
Eyeless scorpion isn't stuck down a blind alley
Eyeless scorpions living in deep inside caves in Mexico have returned to light and regained the ability to see, showing that a specialized way of life is not always an evolutionary blind alley.
Lorenzo Prendini from the American Museum of Natural History in New York, leads a team who have been studying a group of closely related scorpions, many of which have lost their eyes and become pale and unpigmented - both adaptations to life in dark, sunless caves.
Prendini and the team scrutinised nearly 200 physical characteristics of the scorpions to work out how closely related individual species are, including mapping the arrangement of tiny hairs on their pedipalps (the scorpions' large pincers). They then used this data to build a family tree, which revealed that the generalist species living closer to the surface, under stones and leaf litter, have evolved independently more than once from cave-dwelling ancestors.
Until now, it has been widely assumed that when species evolve specialist characters for a particular environment - such as blindness in caves - they cannot reverse that and become less specialised again. Now the scorpions are showing us that they can.
Scorpions first evolved around 450 million years ago and today there are thought to be around 2000 species in the world, but only 23 of them are known to live in the permanent dark deep inside caves - so-called troglobites. The deepest one lives 1km below the surface.
Many of the surface-dwelling scorpions in this area of Mexico were wiped out around 65 million years ago, perhaps by the nearby meteorite impact that some think killed off the dinosaurs.
But we now know that when scorpions evolved to live in caves, they didn't necessarily condemn future generations to remain stuck in the dark, and that loosing eyesight is not an evolutionary dead end.
09:57 - Reading Thoughts with a Brain Scanner
Reading Thoughts with a Brain Scanner
Dr Demis Hassabis, University College London
Chris - Also in the new this week, researchers at University College London have developed a way to read a person's thoughts and basically see what they're seeing in their mind's eye using a brain scanner. Dr. Demis Hassabis is behind this study and he's with us now. Hello, Demis.
Demis - Hello.
Chris - Welcome to the Naked Scientists. Tell us, if you would first of all, what it is you actually have discovered.
Demis - What we did in the study was to basically get volunteers to view three 
short video clips. These are video clips of every day common events like someone posting a letter or someone throwing a piece of trash in a bin. Then what we did was to ask them to memorise those video clips in as much detail as possible, and then a short while later they were placed in the scanner and they were asked to freely recall those three memories in any order they wanted to, and as many times as they wanted to. After the scanning, we analysed their brain scans and we found we were able to tell which one of the three memories they were recalling and at which time, at an above chance level.
Chris - What was the scanner seeing?
Demis - We were focusing on this small region of the brain called the hippocampus that is known to be essential for this kind of memory. We used quite sophisticated machine learning algorithms to try and spot patterns in people's brain scans, and that's what we're able to do here with just the activity patterns in the hippocampus, and we're able to tell from that which memory someone was recalling.
Chris - How is the brain playing out that memory through that brain structure in a way that you're able to eavesdrop on?
Demis - What we think is going on is that when they first see these videos in the training session, the hippocampus is responsible for laying down a memory trace, or a copy of that memory. So that's what allows you to remember something in the future, you basically reactivate that memory trace. So, what we've done here is try and investigate that memory trace directly and come up with a technique that allows us to look at that memory trace directly in vivo in a functioning human brain.
Chris - And how does this inform our understanding of how that part of the brain actually works? Presumably also, how we then extend that into what happens when it goes wrong with aging and dementia and things?
Demis - This study is part of a program of studies that are investigating the fundamental structure of memory. What we'd like to know is things like - what aspects of an experience are preferentially recorded the brain? Obviously, these are important questions because if we can understand how the brain does that, then maybe we can help form therapies for people who have disorders such as Alzheimer's or dementia, where we can try and enhance their memory for the things that they need to remember, over and above other stuff that is not so essential to them.
Chris - And could you extrapolate the study to look into other modalities, other aspects of memory? You just asked people to watch three short films, but could you make it much more detailed? How far do you think you could take this?
Demis - What we're planning to do next, and in the process of doing at the moment, is extending it further into looking at whether, for example, it's the content of a memory or the context, i.e. what happened or where it happened, that actually best defines the memory. That's the start of actually breaking down memories into their components. So we can actually eventually start looking at which features or which aspects of an experience the brain is coding for.
Chris - But of course, it is a little bit artificial because your system had to learn from these people first in order to know what it was looking for and then record back when they did their free imagination and matched the two things together. It's a bit further down the line before presumably you'll be able to put someone in the scanner and then workout what they're thinking about without having pre-learned?
Demis - Yes, that's right. We're long, long away from creating some kind of general purpose, mind reading machine or something. What we did here is that these are predefined memories that we know that the volunteer is going to choose between. Even then we're not 100% accurate. So very much at the moment, it's still fundamental research rather than any kind of application such as that.
Chris - So the HMRC, the Inland Revenue are going to have to wait a little while before they can tell whether people are being absolutely honest with their tax returns in the future.
Demis - That's right. That's right.
Chris - Demis, thank you very much.
Demis - Thank you.
Chris - That's Dr. Demis Hassabis. He is at University College London. If you'd like to read a bit more about the paper he was discussing that he and his colleagues have published is in the journal Current Biology this week.
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