(Image caption: When the two eyes of the observer are presented with fast flickering chromatic gratings in orthogonal orientations, his conscious perception stays constant as a uniform yellow disc, while the early visual area resolves the invisible conflict through binocular rivalry. Credit: IBP)

Human Early Visual Cortex Subconsciously Resolves Invisible Conflicts

Our visual system is constantly bombarded with complex optical information. The input information is often insufficient or ambiguous, leading to potentially conflicting interpretations about the structure of the physical world. The human brain has amazing computational powers to resolve these ambiguities and generate a coherent perception almost instantly. As a way to understand how our brain works, scientists have been fascinated about how the human brain achieves this goal.

When two different images are separately presented to the matching retinal locations of the two eyes, instead of seeing a mixed image, normal observers perceive a spontaneous alternation between the two eyes’ images. This striking visual phenomenon, called binocular rivalry, has been used as a powerful tool by cognitive neuroscientists to study the brain mechanisms that resolve ambiguities to generate conscious perception. This is because in binocular rivalry, conscious experience changes while physical stimuli remain constant.

For the brain to engage the conflict resolution mechanism, an intuitive assumption is that the brain first “detects” the conflict. A central question is whether the conflict needs to be consciously detected for it to be resolved. In the case of binocular rivalry, in which the conflict exists between the two eyes, the question becomes whether binocular rivalry requires conscious awareness of the conflicting information between the two eyes. This is the question investigated in a study jointly conducted by Dr. Zhang Peng and Dr. HE Sheng’s research groups, including graduate student Zou Jinyou, from the Institute of Biophysics of the Chinese Academy of Sciences, published online at PNAS on June 27, 2016. The research question is straightforward: If the conflicting features of the two eyes’ images were invisible, leading to identical perceptual interpretations, would rivalry competition still occur?

The researchers used red-green chromatic gratings, presented in orthogonal orientations to the two eyes, thus producing interocular conflicts. However, the red-green stripes were rendered invisible by counterphase flickering of the pattern at 30 Hz. At this flickering rate, the red-green fused and both gratings were perceived as an identical uniform yellow disc. Although these stripes were invisible, researchers demonstrated that the orientation information was processed in the early visual cortex, but was not available to the parietal and frontal cortical areas.

In a series of creatively designed behavioral experiments, researchers revealed that although perceptually there was no difference between the two eyes’ images, the invisible orientation conflict between the two eyes indeed induced rivalry competitions. An invisible grating to one eye produced rivalry competition with a low contrast visible grating presented to the other eye. Switching from a uniform field to a perceptually matched invisible grating, all without observers noticing any change, produced interocular suppression at approximately 200 ms after the onset of the invisible grating. Furthermore, experiments using briefly presented monocular probes revealed evidence for sustained rivalry competition between two invisible gratings during continuous presentations.

These findings show that the human brain initiates mechanisms, presumably in the sensory cortex with minimal involvement of the fronto-parietal cortex, to resolve conflicting information in visual input even when the conflicting information is not consciously perceived. Researchers conclude that visual competition could occur without conscious representation of the conflicting visual inputs. This forms an interesting and important contrast with early findings made by the same group, i.e., that focused attention is required for conflict resolution in the brain.

good.is
Science Just Confirmed One of Buddhism's Main Ideas

by Aimee Kuvadia

Proving that science and religion can, in fact, overlap, University of British 

Columbia researcher Evan Thompson has confirmed the Buddhist teaching of the not-self, or “anatta,” is more than just a theory.

“Buddhists argue that nothing is constant, everything changes through time, you have a constantly changing stream of consciousness,” he tells Quartz. “And from a neuroscience perspective, the brain and body is constantly in flux. There’s nothing that corresponds to the sense that there’s an unchanging self.”

This reality that nothing stays the same should be liberating, because if people believe it, they’ll no longer define themselves by their thoughts or be limited by a fixed idea of who they are. Their possibilities will be endless.

Buddhist Monks have known for thousands of years what science is just now learning: the mind can be changed by training it

Neuroplasticity, as it’s called, endows people with the ability to grow and evolve, triumphing over bad habits and becoming more like the individuals they want to be.

Still, exactly how consciousness relates to the brain eludes both Buddhism and neuroscience. Buddhists suppose there’s an iteration of consciousness that doesn’t require a physical body; neuroscientists disagree.

“In neuroscience, you’ll often come across people who say the self is an illusion created by the brain,” Thompson says. “My view is that the brain and the body work together in the context of our physical environment to create a sense of self. And it’s misguided to say that just because it’s a construction, it’s an illusion.”

Connecting the Dots

Our brain contains over 100 trillion connections. To analyse how its structure makes it function in certain ways involves building a connectome – a complete map of all the nerves in a typical brain and their connections. This huge job involves imaging large areas of brain with enough resolution to identify the individual nerve cells, and their tangled extensions – dendrites and axons. A new system for producing images like this has recently been developed. Called the brain-wide positioning system, it simultaneously takes pictures of the cell nuclei (shown in red) and whole neurons labelled with fluorescent protein (green). Comparing these two sets of images can help to identify neurons and establish which connections are which. Although this picture was taken in a mouse’s brain, this technology will help us to accurately image individual human brains, which we can use to build up the picture of the human connectome.

Written by Esther Redhouse White

You can also follow BPoD on Twitter and Facebook

Researchers Devise Tool to Improve Imaging of Neuronal Activity in the Brain

In a partnership melding neuroscience and electrical engineering, researchers from UNC-Chapel Hill and NC State University have developed a new technology that will allow neuroscientists to capture images of the brain almost 10 times larger than previously possible – helping them better understand the behavior of neurons in the brain.

Nervous systems are complex. After all, everything that any animal thinks or does is controlled by its nervous system. To better understand how complex nervous systems work, researchers have used an expanding array of ever more sophisticated tools that allow them to actually see what’s going on. In some cases, neuroscience researchers have had to create entirely new tools to advance their work.

This is how an electrical engineering researcher ended up co-authoring a Nature Biotechnology paper with a group of neuroscientists.

A UNC-Chapel Hill research team made up of Jeff Stirman, Ikuko Smith and Spencer Smith wanted to be able to look at “ensemble” neuronal activity related to how mice process visual input. In other words, they wanted to look at activity in neurons across multiple areas at the same time.

To do that, the researchers used a two-photon microscope, which images fluorescence. In this case, it could be used to see which neurons “light up” when active.

The problem was that conventional two-photon microscopy systems could only look at approximately one square millimeter of brain tissue at a time. That made it hard to simultaneously capture neuron activity in different areas.

This is where Michael Kudenov comes in. An assistant professor of electrical and computer engineering at NC State, Kudenov’s area of expertise is remote imaging. His work focuses on developing new instruments and sensors to improve the performance of technologies used in everything from biomedical imaging to agricultural research.

After being contacted by the UNC researchers, Kudenov designed a series of new lenses for the microscope. Stirman further refined the designs and incorporated them into an overall two-photon imaging system that allowed the researchers to scan much larger areas of the brain. Instead of capturing images covering one square millimeter of the brain, they could capture images covering more than 9.5 square millimeters.

This advance allows them to simultaneously scan widely separated populations of neurons.

As the group notes in its Nature Biotechnology paper, this work addresses “a major barrier to progress in two-photon imaging of neuronal activity: the limited field of view.”

wired.co.uk
Why do we sleep? Scientists uncover how late nights can physically change the brain
Sleep deprivation can lead to increased synaptic strength in the brain but decreased memory power
By Amelia Heathman

By Amelia Heathman

We all sleep – some of us less than others – and yet the exact role sleeping plays on our bodies and minds has largely remained elusive.

By focusing on the effects of sleep deprivation on the brain, scientists now believe sleep is needed in order to ensure brain function stays on track, and to prevent connectivity changes.

Christoph Nissen and his team from the University Medical Center Freiburg, in Germany, compared the brain activity of 20 participants. The first study was done after a full night’s sleep while the second study was carried out after a night of sleep deprivation, a total of 24 hours without any sleep.

During both experiments, the scientists applied magnetic pulses to the motor cortex, the area of the brain responsible for controlling movement, in order to activate neurons in the participants’ brains.

From this, the team discovered that sleep deprivation causes significant, so-called ‘connectivity changes’ to occur. In particular, it was found that in sleep-deprived applicants the strength of the pulse needed to produce a muscle response in the left hand was much lower for the sleep deprived participants, suggesting brain excitability was higher after lack of sleep.

Brain excitability refers to the strength of reactions of the brain to a given stimulus or irritation. It is believed that brain excitability reflects the overall strength of connectivity in the area of the brain it is targeting, therefore when it is affected by something like sleep deprivation, excitability changes meaning in a way that causes the strength of synapses in the brain to change.

(excerpt - click the link for the complete article)

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Report Details Pre and Postnatal Brain Defects From Zika

“Imaging is essential for identifying the presence and the severity of the structural changes induced by the infection, especially in the central nervous system,” said the report’s lead author, Fernanda Tovar-Moll, M.D., Ph.D., vice president of the D'Or Institute for Research and Education and professor at the Federal University of Rio de Janeiro, in Rio de Janeiro, Brazil. “Microcephaly is just one of several radiological features.”

The research is in Radiology. (full open access)

Interesting Reviews for Week 34, 2016

Cognitive mechanisms for responding to mimicry from others. Hale, J., & Hamilton, A. F. de C. (2016). Neuroscience & Biobehavioral Reviews, 63, 106–123. http://doi.org/10.1016/j.neubiorev.2016.02.006

Coordinating different representations in the hippocampus. Kelemen, E., & Fenton, A. A. (2016). Neurobiology of Learning and Memory, 129, 50–59. http://doi.org/10.1016/j.nlm.2015.12.011

Tracking the flow of hippocampal computation: Pattern separation, pattern completion, and attractor dynamics. Knierim, J. J., & Neunuebel, J. P. (2016). Neurobiology of Learning and Memory, 129, 38–49. http://doi.org/10.1016/j.nlm.2015.10.008

Pattern separation, completion, and categorisation in the hippocampus and neocortex. Rolls, E. T. (2016). Neurobiology of Learning and Memory, 129, 4–28. http://doi.org/10.1016/j.nlm.2015.07.008

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Giant Artwork Reflects The Gorgeous Complexity of The Human Brain

The new work at The Franklin Institute may be the most complex and detailed artistic depiction of the brain ever.

Your brain has approximately 86 billion neurons joined together through some 100 trillion connections, giving rise to a complex biological machine capable of pulling off amazing feats. Yet it’s difficult to truly grasp the sophistication of this interconnected web of cells.

Now, a new work of art based on actual scientific data provides a glimpse into this complexity.

The 8-by-12-foot gold panel, depicting a sagittal slice of the human brain, blends hand drawing and multiple human brain datasets from several universities. The work was created by Greg Dunn, a neuroscientist-turned-artist, and Brian Edwards, a physicist at the University of Pennsylvania, and goes on display at The Franklin Institute in Philadelphia. 

“The human brain is insanely complicated,” Dunn said. “Rather than being told that your brain has 80 billion neurons, you can see with your own eyes what the activity of 500,000 of them looks like, and that has a much greater capacity to make an emotional impact than does a factoid in a book someplace.”

To reflect the neural activity within the brain, Dunn and Edwards have developed a technique called micro-etching: They paint the neurons by making microscopic ridges on a reflective sheet in such a way that they catch and reflect light from certain angles. When the light source moves in relation to the gold panel, the image appears to be animated, as if waves of activity are sweeping through it.

First, the visual cortex at the back of the brain lights up, then light propagates to the rest of the brain, gleaming and dimming in various regions — just as neurons would signal inside a real brain when you look at a piece of art.

That’s the idea behind the name of Dunn and Edwards’ piece: “Self Reflected.” It’s basically an animated painting of your brain perceiving itself in an animated painting.

To make the artwork resemble a real brain as closely as possible, the artists used actual MRI scans and human brain maps, but the datasets were not detailed enough. “There were a lot of holes to fill in,” Dunn said. Several students working with the duo explored scientific literature to figure out what types of neurons are in a given brain region, what they look like and what they are connected to. Then the artists drew each neuron.

Dunn and Edwards then used data from DTI scans — a special type of imaging that maps bundles of white matter connecting different regions of the brain. This completed the picture, and the results were scanned into a computer. Using photolithography, the artists etched the image onto a panel covered with gold leaf.

“A lot of times in science and engineering, we take a complex object and distill it down to its bare essential components, and study that component really well” Edwards said. But when it comes to the brain, understanding one neuron is very different from understanding how billions of neurons work together and give rise to consciousness.

“Of course, we can’t explain consciousness through an art piece, but we can give a sense of the fact that it is more complicated than just a few neurons,” he added.

The artists hope their work will inspire people, even professional neuroscientists, “to take a moment and remember that our brains are absolutely insanely beautiful and they are buzzing with activity every instant of our lives,” Dunn said. “Everybody takes it for granted, but we have, at the very core of our being, the most complex machine in the entire universe.”

Image 1: A computer image of “Self Reflected,” an etching of a human brain created by artists Greg Dunn and Brian Edwards.

Image 2: A close-up of the cerebellum in the finished work.

Image 3: A close-up of the motor cortex in the finished work.

Image 4: This is what “Self Reflected” looks like when it’s illuminated with all white light.

Image 5: Pons and brainstem close up.

Image 6: Putkinje neurons - color encodes reflective position in microetching.

Image 7: Primary visual cortex in the calcarine fissure.

Image 8: Basal ganglia and connected circuitry.

Image 9: Parietal cortex.

Image 10: Cerebellum.

Credit for all Images: Greg Dunn“Self Reflected”

Source: The Huffington Post (by Bahar Gholipour)

Chemicals Banned 40 Years Ago Linked to Increased Autism Risk Today

Chemicals used in certain pesticides and as insulating material banned in the 1970s may still be haunting us, according to new research that suggests links between higher levels of exposure during pregnancy and significantly increased odds of autism spectrum disorder in children.

The research is in Environmental Health Perspectives. (full access paywall)

How to Hijack Your Brain’s Reward Circuitry and Make it Work *For* You

The reward circuit of the brain has several component parts, each of which plays a distinct but interconnected role.  We’re going to focus on the five most important parts: the ventral tegmental area (VTA), the ventral striatum, the amygdala, the hippocampus, and the cerebral cortex.

Read the rest of the article here!

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Book Recommendations: Books that have helped me think and write critically when it comes to scientific literature. I’ve never gotten below a 4.0/1st in a lab report.

This post will be especially helpful for those taking psychology, neuropsychology, neuroscience, cognitive neuroscience, pharmacy etc. All books are written by world leading academic researchers and are very well referenced. 

Bad Science by Dr Ben Goldacre - 342pgs, Age 11+.

If there is a book on this list that you read, let it be this! Dr Goldacre focuses on the misuse of science by journalists, homeopaths, schools and big pharmaceutical companies. The book has a great segment on understanding “The Placebo Effect”. Other topics include; Brain Gym, misleading cosmetic adverts, issues with vitamin pills and “toxins”. He has a blog he runs Badscience.net that has great free articles! The book is beautifully referenced and really easy to read, definitely worth investing in. If you can’t spend money on the book just yet, there is a similar free talk here

Drugs: Without the Hot Air by Prof David Nutt - 316pgs, Age 12+.

Prof Nutt incurred the wrath of the UK government when he put forth research papers stating that alcohol and tobacco were more harmful than many illegal drugs, including LSD, ecstasy and cannabis. In “Drugs”, he talks us through the science of what drugs are and how they work, quantifying and comparing the harms caused by different drugs, as well as drug addiction. This book is a great starting point and has educated me on all major drugs better than any textbook has. It’s written in simple English with numerous references and even has a wonderful segment titled “What should I tell my kids about drugs?”. I have had the pleasure of meeting Prof Nutt multiple times and given the slander he has endured, he remains passionate and dedicated to his field. Prof Nutt runs a website aimed at the general public Drugscience.org. There is a similar free talk here.

Bad Pharma by Dr Ben Goldacre - 404pgs, Age 15+.

Another gem by Dr Goldacre, this is a slightly heavier text than the above two books but is a must read for those going into pharmacy or research. Bad Pharma explains where new drugs come from and issues with missing data in clinical trials. Companies run bad trials on their own drugs, which distort and exaggerate the benefits by design. When these trials produce unflattering results, the data is simply buried. Dr Goldacre discusses the issues with design and also the harms of not making the missing trial data available. This book is not ‘anti-drug’, this book highlights issues with publication bias and how this needs to be and can be mended in order for doctors and patients to make better informed decisions on the drugs they are prescribing/prescribed.There is a similar free talk here.

The Man who Mistook his Wife for a Hat by Dr Oliver Sacks - 246pgs, Age 11+.

Written by the late Dr Oliver Sacks, this was the first book I purchased at the age of 13 in the field of neurology that made me go nuts for the brain. As a huge fan of Roald Dahl’s style, this book was just perfect. Dr Sacks turned patient case studies into short stories, inviting you into the incredible world of neurological disorders. The following phenomena are covered: visual agnosias, memory loss, Parkinsonion-symptoms, hallucinations etc. Dr Oliver Sacks has multiple books that are worth investing in, have a look at  Oliversacks.com. There is a similar free talk here.

Phantoms in the Brain by Dr V. S. Ramachandran - 257pgs, Age 15+.

Ramachandran, through his research into brain damage, has discovered that the brain is continually organising itself in response to change. Phantoms in the Brain explores case studies and experiments invented by Dr Ramachandran like the Mirror Box to help understand the underlying issues. Examples of the case studies involve a woman who persists that her left arm is not paralysed (albeit her entire leftside is paralysed) and a young man loses his right arm in a motorcycle accident, yet he continues to feel a phantom arm with vivid sensation of movement. In a series of experiments using nothing more than Q-tips and dribbles of warm water the young man helped Dr Ramachandran discover how the brain is remapped after injury. This book is really enjoyable and is a slightly more in-depth read than The Man who Mistook his Wife for a Hat. There is a similar free talk here.  

The Lucifer Effect by Dr Philip Zimbardo - 488pgs, Age 18+ (due to explicit images).

Prof Zimbardo provides an in-depth analysis of his classic Stanford Prison Experiment, and his personal experiences as an expert witness for one of the Abu Ghraib prison guards, raising fundamental questions about the nature of good and evil. This book has really interesting commentaries on The Columbine Shooting, People’s Temple Mass Suicide, Prison Abuse in Afghanistan etc. I enjoyed the book but it does get really repetitive (it definitely could have been made shorter by 100 pages), the publishers also use a really small font. There is a similar free talk here


Ages have been mentioned not as restrictions but as guidelines in terms of the writing style and sensitivity of the literature. Every book mentioned above doesn’t need to be read chronologically, from cover-to-cover. They have been compiled in such a way that you can dip in and out of the chapters without confusion. Lovely!  All free talks are given by the authors and they cover the same topics that are mentioned in the books. 

If you ever wish to discuss the literature, do get in touch with me!