neurosciences

James Bond: Miss Anders, I didn’t recognize you with your clothes on.

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Ghost illusion created in the lab

On June 29, 1970, mountaineer Reinhold Messner had an unusual experience. Recounting his descent down the virgin summit of Nanga Parbat with his brother, freezing, exhausted, and oxygen-starved in the vast barren landscape, he recalls, “Suddenly there was a third climber with us… a little to my right, a few steps behind me, just outside my field of vision.”

It was invisible, but there. Stories like this have been reported countless times by mountaineers, explorers, and survivors, as well as by people who have been widowed, but also by patients suffering from neurological or psychiatric disorders. They commonly describe a presence that is felt but unseen, akin to a guardian angel or a demon. Inexplicable, illusory, and persistent.

Olaf Blanke’s research team at EPFL has now unveiled this ghost. The team was able to recreate the illusion of a similar presence in the laboratory and provide a simple explanation. They showed that the “feeling of a presence” actually results from an alteration of sensorimotor brain signals, which are involved in generating self-awareness by integrating information from our movements and our body’s position in space.

{ EurekAlert | Continue reading | more }

Plato has Socrates describe a gathering of people who have lived chained to the wall of a cave all of their lives, facing a blank wall

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We assume that we can see the world around us in sharp detail. In fact, our eyes can only process a fraction of our surroundings precisely. In a series of experiments, psychologists at Bielefeld University have been investigating how the brain fools us into believing that we see in sharp detail. The results have been published in the scientific magazine ‘Journal of Experimental Psychology: General.’ Its central finding is that our nervous system uses past visual experiences to predict how blurred objects would look in sharp detail.

{ Universität Bielefeld | Continue reading }

related { Scientists have found “hidden” brain activity that can indicate if a vegetative patient is aware }

‘Two simple words in the English language: I forgot!’ –Steve Martin

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In December last year, researchers Brian Dias and Kerry Ressler made a splash with a paper seeming to show that memories can be inherited.

This article, published in Nature Neuroscience, reported that if adult mice are taught to be afraid of a particular smell, then their children will also fear it. Which is pretty wild. Epigenetics was proposed as the mechanism.

Now, however, psychologist Gregory Francis says that the data Dias and Ressler published are just too good to be true.

{ Neuroskeptic | Continue reading }

When I to sulphurous and tormenting flames must render up myself

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Have you ever felt lost and alone? If so, this experience probably involved your hippocampus, a seahorse-shaped structure in the middle of the brain. About 40 years ago, scientists with electrodes discovered that some neurons in the hippocampus fire each time an animal passes through a particular location in its environment. These neurons, called place cells, are thought to function as a cognitive map that enables navigation and spatial memory.

Place cells are typically studied by recording from the hippocampus of a rodent navigating through a laboratory maze. But in the real world, rats can cover a lot of ground. For example, many rats leave their filthy sewer bunkers every night to enter the cozy bedrooms of innocent sleeping children.

In a recent paper, esteemed neuroscientist Dr. Dylan Rich and colleagues investigated how place cells encode very large spaces. Specifically, they asked: how are new place cells recruited to the network as a rat explores a truly giant maze?

{ Sick papes | Continue reading }

One by one they were all becoming shades

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We will review evidence from neuroscience, complex network research and evolution theory and demonstrate that — at least in terms of psychopharmacological intervention — on the basis of our understanding of brain function it seems inconceivable that there ever will be a drug that has the desired effect without undesirable side effects.

{ Neuroethics | Continue reading }

photo { Hannes Caspar }

Turns out this principal is a religious fanatic, and he thinks I’m possessed by some sort of dick devil

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Some people can handle stressful situations better than others, and it’s not all in their genes: Even identical twins show differences in how they respond.

Researchers have identified a specific electrical pattern in the brains of genetically identical mice that predicts how well individual animals will fare in stressful situations.

The findings may eventually help researchers prevent potential consequences of chronic stress — such as post-traumatic stress disorder, depression and other psychiatric disorders — in people who are prone to these problems.

{ EurekAlert | Continue reading }

‘Friends have all things in common.’ –Plato

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Everybody knows that men are women have some biological differences – different sizes of brains and different hormones. It wouldn’t be too surprising if there were some neurological differences too. The thing is, we also know that we treat men and women differently from the moment they’re born, in almost all areas of life. Brains respond to the demands we make of them, and men and women have different demands placed on them. […]

They report finding significant differences between the sexes, but don’t show the statistics that allow the reader to evaluate the size of any sex difference against other factors such as age or individual variability. […] A significant sex difference could be tiny compared to the differences between people of different ages, or compared to the normal differences between individuals.

{ The Conversation | Continue reading }

The most important thing to take from this research is – as the authors report – increasing gender equality disproportionately benefits women. This is because – no surprise! – gender inequality disproportionately disadvantages women. […] But the provocative suggestion of this study is that as societies develop we won’t necessarily see all gender differences go away. Some cognitive differences may actually increase when women are at less of a disadvantage.

{ Mind Hacks | Continue reading }

In order to determine the characteristics of non-philosophy, we frame it in opposition to an image of an established paradigm: Deconstruction

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“I looked up at the shower head, and it was as if the water droplets had stopped in mid-air” […]

Although Baker is perhaps the most dramatic case, a smattering of strikingly similar accounts can be found, intermittently, in medical literature. There are reports of time speeding up – so called “zeitraffer” phenomenon – and also more fragmentary experiences called “akinetopsia”, in which motion momentarily stops.

For instance, travelling home one day, one 61-year-old woman reported that the movement of the closing train doors, and fellow passengers, was in slow motion and “broken up”, as if in “freeze frames”. A 58-year-old Japanese man, meanwhile, seemed to be experiencing life like a badly dubbed movie; in conversation, he found that although others’ voices sounded normal, they were out of sync with their faces. […]

One explanation for this double-failure is that our motion perception system has its own stopwatch, recording how fast things are moving across our vision – and when this is disrupted by brain injury, the world stands still. For Baker, stepping into the shower might have exacerbated the problem, since the warm water would have drawn the blood away from the brain to the extremities of the body, further disturbing the brain’s processing.

Another explanation comes from the discovery that our brain records its perceptions in discrete “snapshots”, like the frames of a film reel. “The healthy brain reconstructs the experience and glues together the different frames,” says Rufin VanRullen at the French Centre for Brain and Cognition Research in Toulouse, “but if brain damage destroys the glue, you might only see the snapshots.”

{ BBC | Continue reading }

A man against capital punishment is accused of murdering a fellow activist and is sent to death row

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It’s a question that has plagued philosophers and scientists for thousands of years: Is free will an illusion?

Now, a new study suggests that free will may arise from a hidden signal buried in the “background noise” of chaotic electrical activity in the brain, and that this activity occurs almost a second before people consciously decide to do something. […]

Experiments performed in the 1970s also raised doubts about human volition. Those studies, conducted by the late neuroscientist Benjamin Libet, revealed that the region of the brain that plans and executes movement, called the motor cortex, fired prior to people’s decision to press a button, suggesting this part of the brain “makes up its mind” before peoples’ conscious decision making kicks in.

To understand more about conscious decision making, Bengson’s team used electroencephalography (EEG) to measure the brain waves of 19 undergraduates as they looked at a screen and were cued to make a random decision about whether to look right or left.

When people made their decision, a characteristic signal registered that choice as a wave of electrical activity that spread across specific brain regions.

But in a fascinating twist, other electrical activity emanating from the back of the head predicted people’s decisions up to 800 milliseconds before the signature of conscious decision making emerged.

{ Live Science | Continue reading }

related { Searching for the “Free Will” Neuron }

‘A place void of all light, which bellows like the sea in tempest.’ –Dante

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Some people report that in fear-related situations time seems to slowdown. That is to say, for example, during a car crash the event takes much longer from the point of a person experiencing the crash than the observer. But how and why the brain creates this slow motion experience is not completely understood. […]

In a situation where emotions are involved, there is an increased amygdala activity and a consequent increase in memory recording. When a person is asked to recall a fear-related event, the amount of details that he/she can recall is substantially increased compared to normal situation. However, the brain, not used to recalling so many details, is left to think that the event must have taken longer than it really did.

It is ‘the trick of memory’ as Eagleman puts it; the brain is not used to these exceptional circumstances and therefore, it tricks itself into false time perception.

{ The Question Gene | Continue reading }

Narcissists can feel empathy, research finds

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Those parents at the park taking all those photos are actually paying less attention to the moment, she says, because they’re focused on the act of taking the photo.

“Then they’ve got a thousand photos, and then they just dump the photos somewhere and don’t really look at them very much, ’cause it’s too difficult to tag them and organize them,” says Maryanne Garry, a psychology professor at the Victoria University of Wellington in New Zealand. […]

Henkel, who researches human memory at Fairfield University in Connecticut, found what she called a “photo-taking impairment effect.”

“The objects that they had taken photos of — they actually remembered fewer of them, and remembered fewer details about those objects. Like, how was this statue’s hands positioned, or what was this statue wearing on its head. They remembered fewer of the details if they took photos of them, rather than if they had just looked at them,” she says.

Henkel says her students’ memories were impaired because relying on an external memory aid means you subconsciously count on the camera to remember the details for you.

{ NPR | Continue reading }

photo { Florian Maier-Aichen, Untitled (Cloud), 2001 }

An instant under the mirror

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Important peculiarities of the human memory system:

— A remarkable capacity for storing information is coupled with a highly fallible retrieval process.

— What is accessible in memory is highly dependent on the current environmental, interpersonal, emotional and body-state cues.

— Retrieving information from memory is a dynamic process that alters the subsequent state of the system.

— Access to competing memory representations regresses towards the earlier representation over time.

{ Robert Bjork | Continue reading }