Electric fish generate electric pulses to communicate with other fish and sense their surroundings. Some species broadcast shorter electric pulses, while others send out long ones. But all that zip-zapping in the water can get confusing. The fish need to filter out their own pulses so they can identify external messages and only respond to those signals.
A solution to this problem is a brain function called a corollary discharge. It’s sort of like a negative copy of the original message — something that tells the fish: Ignore this.
But an animal’s brain doesn’t have to block sensory inputs during the entire message to effectively ignore its own signal, according to new research from biologists at Washington University in St. Louis.
Instead, the inhibitory signal — that call to ignore — is delayed in fish that communicate using longer electric pulses, versus those using shorter pulses.
“In fish that communicate with longer pulses, sensory responses to their own pulse are delayed,” said Bruce Carlson, professor of biology in Arts & Sciences. “Thus, a delayed corollary discharge optimally blocks electrosensory responses to the fish’s own signal.”
A brief, well-defined period of inhibition keeps electric fish from missing out on other important external signals, Carlson said.
Scientists have known about corollary discharges since the 1950s. In the decades since, corollary discharges have been found in many different species and sensory systems, but it remained unknown how corollary discharges were modified as communication signals evolved.
Previous work on corollary discharge in electric fish had been done with species that communicate using short-duration electric pulses, those lasting less than 1 millisecond.
For their new study, Carlson and Fukutomi included these fish and five additional species that communicate using electrical pulses ranging in duration from 0.1 to 10 milliseconds.
“We found the sensory neurons respond with spikes in a narrow time window regardless of pulse duration,” Fukutomi said. “These spikes occurred in a specific part of the self-generated pulse, the first peak of the pulse. In addition, we compared the time courses between the corollary discharge inhibition and the pulse and found that the time-shifted inhibition overlapped the first peak of the electric pulse.
“Time-shifted inhibition is a reasonable change because longer-lasting inhibition would result in an unnecessarily long insensitive period,” he said. “I am impressed that there is a solution that makes more sense in real organisms than we might have expected.”
The new findings have broader implications for understanding the evolution of brains.
“Despite the complexity of sensory and motor systems working together to deal with the problem of separating self-generated from external signals, it seems like the principle is very simple,” Carlson said. “The systems talk to each other. Somehow, they adjust to even widespread, dramatic changes in signals over short periods of evolutionary time.”
As part of continuing research, Carlson and Fukutomi are working to pinpoint the place in the brain circuit where the delay is adjusted, and how that adjustment is made. They are also investigating how the inhibition delay changes over the individual lifetime of a fish.
The researchers also recently co-authored a new review paper on the contributions of electric fish to the study of corollary discharge in Frontiers in Integrative Neuroscience.
Even though humans aren’t able to generate electric fields, research on corollary discharge in electric fish has provided insights that are important in medical science as well as basic science. Dysfunction of corollary discharge may be related to psychiatric diseases such as schizophrenia in humans, for example.
“I love strange creatures, including electric fish,” Fukutomi said. “We can only feel electricity as pain, but we never sense electricity as the fish does.
“Surprisingly, electrosensory systems share a lot of general features with other sensory systems,” he said. “I am very excited to be studying these fish.”
Xbox Series X, Series S India Pre-Order Time, Online Retailers Announced
India pre-orders for Xbox Series X and Series S will go live at 9am IST on Tuesday, September 22, Microsoft India has announced. Both Series X and Series S will be available on Amazon, Flipkart, and Reliance Digital’s online store. No offline stores have been announced. India is one of 37 countries where the new Xbox Series family will be up for pre-order on Tuesday, in addition to the US, the UK, Canada, Australia, New Zealand, and parts of Europe, Middle East, and Africa.
While the Xbox Series X and Series S pre-order date was announced alongside the prices — Rs. 49,990 for the Series X and Rs. 34,990 for the Series S — and launch date (November 10) last week, we didn’t have details on an exact pre-order time and where it would be available. Now we know. Gadgets 360 has also reached out to Microsoft India on details regarding special discounts (credit / debit card cashback offers) and financing options (no-cost EMIs), and we will update if we hear back.
For those outside India, here’s where you can pre-order the Xbox Series X and Series S. In the US, pre-orders go live Tuesday, September 22 at 8am PT / 11am ET on Microsoft Store, Amazon, Best Buy, GameStop, Walmart, Target, Sam’s Club, Newegg, and other participating retailers. Up north in Canada, pre-orders also go live at 8am PT / 11am ET on Microsoft Store, Amazon, Walmart, Best Buy, EB Games, The Source, and other participating retailers.
Across the pond in the UK, Xbox Series X and Series S pre-orders will be available Tuesday 8am BST on Microsoft Store, GAME, Amazon, Dixons, Currys PC World, Argos, John Lewis, Smyths Toys, VERY, AO, Tesco, Simply Game, Shopto and other participating retailers. In mainland Europe, as well as the Middle East and Africa, you can pre-order online starting at 9am CEST on Microsoft Store, Amazon, MediaMarkt, GameStop, FNAC, Elkjøp/Elgiganten, and other participating retailers.
Down under all the way in Australia, Xbox Series X and Series S pre-orders kick off Tuesday, September 22 at 8am AEST on Microsoft Store, JB Hifi, EB Games, Telstra, Harvey Norman, and other participating retailers. And in nearby New Zealand, you can pre-order both new Xbox Series consoles starting 8am NZST on Microsoft Store, JB HiFi, EB Games, Spark, and other participating retailers.
Xbox Series S and Series X will launch in 37 countries — including India — on November 10, and 41 countries during “holiday 2020”.
Netflix engineer builds SnapCamera lens to bring a comic book vibe to video calls
Snapchat’s Lens Studio has built-in recognition for 5 hand gestures that means you don’t have to unmute to say hi or BRB.
If you need something to ease the frustration of conversations via video chat, consider a new Snap Camera lens. Cameron Hunter, a senior software engineer at Netflix, created Meeting Gestures. Instead of unmuting to say, “hi,” or “ok,” this lens communicates the information with a gesture instead.
When you raise your index finger, “Question” pops up on your video feed in a red comic-book word bubble. Hunter used the smile recognition in Snap Camera to display “ha, ha” bubbles. Moving outside the frame brings up “I’ll be right back” in a word bubble that fills the screen.
He tweeted that he used five built-in hand gestures in Snap Lens Studio to create the lens.
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Snap Camera is simple to install and use. It works on Zoom, Skype, Microsoft Teams, and Twitch. Once you’ve got Snap Camera installed, set your video conference camera to Snap Camera. You have to run Snap Camera and your web conferencing software at the same time.
From the home screen of Snap Camera, paste this into the search box: https://www.snapchat.com/unlock/?type=SNAPCODE&uuid=16839bd69c67492696d6ccf1296ad31e&metadata=01
Most lenses have a more user friendly name. On Tuesday, Hunter said he was working with SnapChat to resolve an issue with the name of the lens.
That link will bring up Hunter’s lens. The word bubbles will look backward to you but will read correctly for viewers.
Build your own lens
Hunter’s Twitter post sparked several ideas about additional gestures for the Snap Camera library, including sign language. Hunter tweeted that you can lock messages or images to tracked objects such as a hand or a head. Snap Lens Studio does not support the middle finger gesture. Twitter user Johnny Xmas suggested the Meeting Gestures lens would be helpful during a large-scale scrum.
Ryan Brown, content and creative lead at Twitter, built his own meeting friendly lens. When you hold up an open palm, a flash of fire pops up and a heart flashes up when you hold up an index finger.
Lens Studio has a guide that explains how to make a lens. You can create Face Lenses for front camera experiences and World Lenses for rear camera experiences.
There are numerous templates for both types. The General section covers 2D, 3D, face tracking, audio, and scripting. You can even define a hint that will display for a user when a lens is turned on. There are also guidelines on how to submit a lens to the Snap Camera gallery.
New cancer screening study could affect treatment for thousands in the UK
The first UK study to estimate the proportion of womb cancers caused by an inherited cancer predisposition called Lynch syndrome has been carried out by The University of Manchester.
Almost 3% of womb cancers are linked to a hereditary condition named Lynch syndrome, according to new clinical research findings published in the journal, PLOS Medicine. The results of the new study have caused the National Institute for Health and Care Excellence (NICE) to advocate a change in testing practices across the UK.
Knowing that a person has Lynch syndrome can help determine which cancer treatments are likely to be successful. It also means that patients’ family members can be screened for the syndrome and those who test positive can be offered bowel-cancer screening to detect and remove pre-cancerous polyps. This has been shown to save lives. Whilst the link between Lynch syndrome and bowel cancer is well established, however, the link with womb cancers is less well studied.
The University of Manchester has now led the first prospective UK study to determine the prevalence of Lynch syndrome in 500 women newly diagnosed with womb cancer and found 16 to have Lynch syndrome.
Thirteen of the women did not know they had Lynch syndrome and their diagnosis prompted genetics referral, cascade testing of family members and access to prevention interventions (like colonoscopy and aspirin chemoprevention) that will hopefully prevent them (and their relatives) developing other cancers in the future.
The study was led by Professor Emma Crosbie at The University of Manchester and supported by the Medical Research Council and the National Institute for Health Research Manchester Biomedical Research Centre.
Professor Crosbie said: “If all women with womb cancer were tested for Lynch syndrome, we would identify around 220 women every year who didn’t know they had it, plus on average 3 family members per index case. This is around 1,000 people every year in the UK alone who would be diagnosed with Lynch syndrome and empowered to reduce their future cancer risk through proven interventions.
“More people could be enrolled in cancer prevention and screening programmes, and this may reduce the number of people being diagnosed with cancer, particularly at a young age.
“Because womb cancer often presents first, it may be the first sign that a patient has Lynch syndrome and is therefore at risk of developing bowel cancer and other Lynch-related cancers later in life. Finding out they have Lynch syndrome could enable them to take action to protect themselves and their family members from these cancers.”
A similar proportion of bowel cancers are caused by Lynch syndrome, which has led to guidance from the National Institute for Health and Care Excellence (NICE) that anyone diagnosed with bowel cancer should be tested for the condition.
Source: University of Manchester
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