October 12, 2016 Although commonly associated with psychiatric disorders, healthy people can also have visual hallucinations after taking drugs, being sleep deprived or suffering migraines. Credit: Shutterstock A new method for inducing, modelling and measuring visual hallucinations in healthy individuals suggests these complex experiences share a common underlying mechanism with normal visual perception, UNSW researchers say. Although commonly associated with psychiatric disorders, healthy people can also have visual hallucinations after taking drugs, being sleep deprived or suffering migraines. These involuntary experiences are thought to arise when spontaneous changes in the brain temporarily hijack visual function, but the exact causes and underlying mechanisms aren't fully understood. "We have known for more than 100 years that flickering light can cause almost anyone to experience a hallucination," says UNSW Associate Professor Joel Pearson from the School of Psychology. "However, the unpredictability, complexity and personal nature of these hallucinations make them difficult to measure scientifically," he says. The content of these visions – including colours and forms that appear and how they move around – are constantly changing over time and are inherently subjective. "Previous studies have typically relied on drawings and verbal descriptions, but these don't provide us with a way to precisely identify the mechanisms in our brain that cause hallucinations," says Pearson. One of the grand challenges in the field has been inducing hallucinations in the lab that are stable and identical for all people. Now, thanks to Pearson and his team, this is possible. It means they can scientifically measure the strength of hallucinations without relying on subjective descriptions. Using a flickering white light against a black backdrop, the UNSW team was able to induce visual hallucinations in a number of healthy volunteers, causing them to 'see' pale grey blobs. It is recommended that anyone with a history of migraines, epilepsy or psychiatric disorders refrain from watching the video below. You should see pale grey blobs appear in the ring and rotate around it, first in one direction and then the other. "With our technique we get rid of the unpredictability. People don't see windmills, lines, or different colours; they just hallucinate grey blobs. Once the hallucination is stable like this, with just the blobs, we can start to objectively investigate the underlying mechanisms," says Pearson. "Nobody has been able to do this before, because they haven't been able to overcome this key challenge. Understanding how Parkinson’s patients experience visual mental imagery is providing hope that their uncontrolled hallucinations can be treated. Credit: defeatparkinsons.com Using new techniques, they were able to measure the strength of the hallucinations, and pinpoint that the hallucinations were arising inside the visual cortex – the region of the brain that processes visual information and allows us to see. "The induced hallucinations also seem to obey many of the same laws and properties as normal visual perception," says Pearson. The team's results are published today in the journal eLife and comes as Australia marks Mental Health Week. Pearson says the next step is to investigate whether the experimental methods can be used to model hallucinations produced by psychiatric disorders. The team has begun working with people with Parkinson's disease. "Not everyone who gets Parkinson's has hallucinations," says Pearson. "If we can use these models to study their hallucinations, we can find out what might be causing them, and hopefully learn more about other symptoms that accompany natural hallucinogenic states." Healthy volunteers reported seeing pale grey blobs appear in the ring and rotate around it, first in one direction and then the other. Credit: Joel Pearson "It will help inform us about what is happening pathologically in the brain during hallucinations, and ultimately help us develop new treatments." "As we mark Mental Health Week, this study highlights the urgent importance of translational science for understanding and developing new treatments for mental health. "The World Economic Forum has predicted mental health care will cost around six trillion a year by 2030, so we urgently need new methods and laboratory models to understand mental illness," says Pearson. Flickering lights and a pale grey blob – how the scientists induced and measured hallucinations The volunteers were university students with no history of migraines or psychiatric disorders. The students watched an image of a plain white ring flicker on and off up to around 130 times per second against a black background. To measure the hallucinations, the team placed a second ring marked with permanent grey blobs inside the white ring. By stating whether the hallucinated blobs were lighter or darker than the real blobs, the participants were able to communicate how strong the hallucination was. Credit: Joel Pearson All individuals reported seeing pale grey blobs appear in the ring and rotate around it, first in one direction and then the other. To measure the hallucinations, the team placed a second ring marked with permanent grey blobs inside the white ring. By stating whether the hallucinated blobs were lighter or darker than the real blobs, the participants were able to communicate how strong the hallucination was. Using behavioural science techniques, the team was able to demonstrate that the hallucinations were arising inside the visual cortex, without the need for MRI scans. They did this by showing volunteers two flickering-lights – one for each eye, displayed out of synchrony. These lights were flashing about 2.5 times per second – a relatively slow rate, which normally doesn't induce strong hallucinations, explains Pearson. But the volunteers were experiencing hallucinations consistent with lights flashing about 5 times per second. "They were combining the signals from the two eyes. This really only happens in the visual cortex, not in the eye, or other initial processing areas of the brain," says Pearson. Working with mathematicians from the University of Pittsburgh, the team developed neural models of the visual cortex to try to understand what was happening. Pearson likens these models to the vibrational phenomena known as cymatics, where sound frequencies can be seen pushing sand grains into geometric patterns. "Rather than a metal plate and sand, we're talking about the visual cortex, where we see these reverberating, self-organising patterns of activity. We think this could be how the brain is creating the hallucination, and it might also help to explain normal consciousness, and our experience of what's happening around us every day." Provided by: University of New South Wales Video:"http://medicalxpress.com/news/2016-10-breakthrough-door-hallucinations-scientifically.html http://medicalxpress.com/news/2016-10-breakthrough-door-hallucinations-scientifically.html
Many people struggle to learning new things. But what if I told you the problem might not be with what you are learning, but with how you are learning it?
A2 Grammar practice: prepositions of place and movement. Key provided.Here you are more similar practice:https://en.islcollective.com/resources/printables/worksheets_doc_docx/prepositions_of_place_and_movement/prepositions-of-movement/99153 - ESL worksheets
Phrasal Verbs – CLEAR, Definitions and Example Sentences Clear away Meaning: to take away sth to clear a place Example Sentence: You should clear away all your toys before bedtime. Clear out (of) Meaning: to leave a place Example Sentence: She’ll clear out of the house in two weeks. Clear sb off Meaning: to make sb go away from a place Example Sentence: The police’ll use dogs to clear the protesters off the road. Clear up Meaning: to solve or explain Example Sentence: I think the trouble will clear up in a couple of days. Clear up Meaning: to tidy Example Sentence: Did you clear
Designed for ESL students, for practice with simple prepositions of place: in, on, under, near, next to, behind, between, in front of. The first page is for studying; the second page is a practice worksheet.
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In this post, we will learn naming alkenes by the IUPAC Nomenclature Rules including when the E and Z configuration needs to be addressed.
By contributing writer Colleen Are you studying the human body with your kids this year? Kids of all ages can benefit from learning about their body systems, how they work, and how to keep themselves healthy. Since little ones often have ear infections, the ear and its canals is a great place to start. Even the […]
Lucky number thirteen! I love the number 13 - it's my favorite. Hubby and I were married on Friday the 13th and 13 has always felt like a pretty lucky number to me. Let's celebrate my 13th follower!!!!! For our social studies unit on families we talked about how we and our family change over time. Click here for a cute little timeline worksheet. Click here for a different look of the same worksheet.
Hello Everyone! One wonderful perk about the 15 hour drive home? I was able to put the finishing touches on my Landforms unit. This unit is coming up in our curriculum, so I'm glad I had time to organize and put everything together. This mini unit includes almost 70 pages of learning centered around exploration of landforms. There are some social studies activities (of course), some ELA (abc order, vocabulary, antonyms, written expression), some math, and a couple of craft connections. I hope you can use even a small part of this. Here are a few pics of the unit. Landforms book inspired by AIMS curric. Unit includes patterns! mystery picture includes clues with mixed math practice If you are interested, please click here for your free unit! Well, spring break is almost over. I have missed my kids so much!! Can't wait to see them! But that's going to have to wait one extra day as I have jury duty tomorrow. Thank goodness for a wonderful substitute teacher who just so happens to be a dear friend. My kids are in good hands!! Next up? Natural resources and geometry units! Stay tuned!! As always, thanks for taking time to take a peek! I appreciate each and every one of you!! Take care! Joyfully! Nancy
Sailors didn't have it easy, here's a look at their menu.
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Happy Sunday. I'm linking up with Collaboration Cuties to share a favorite text to use with social studies. One of my favorite social studies books is Mapping Penny's World by Loreen Leedy. This book is very similar to Me On the Map by Joan Sweeney (another favorite). In this book Lisa learns about different types of maps. She uses her dog Penny to complete a mapping project. I love this book because of the illustrations, the in depth explanation of maps, and because it is part of a series of three books that feature Penny (Measuring Penny and It's Probably Penny). My first graders love all of these books. Below you will find a freebie to use with Mapping Penny's World. Students can draw a maps of their bedrooms and create a key to go with their maps. Click on the picture below if you would like a copy. The clip art is from Scrappin Doodles. I highly recommend Mapping Penny's World and all of the other Penny books for your classroom library. The stories are cute, the information is abundant, and your kids will really enjoy them. For more tried and true recommendation head on over to Collaboration Cuties and check out the other Must Read Mentor Texts for social studies. Thanks for reading and have a great week.
