Archive for the 'Neuroscience' Category

Oct 23 2014

A Brain-Training Update

Published by under Neuroscience

Can playing video games or specifically designed computer games improve your cognitive function? There are many companies who claim that they can and who would like to sell you such games that they claim are “scientifically designed.”

So-called brain-training is a burgeoning business, with perhaps the best known product being Lumosity. Lumosity promises:

“Scientifically designed games: Lumosity scientists study many common neuropsychological tasks, design some new ones, and transform these tasks into fun, challenging games.”

They claim to be a “leader in the science of brain training,” and include a list of 13 studies that allegedly show Lumosity is effective. Many of the studies do not even test efficacy, and strangely the list does not include this recent study from August 2014 showing that Lumosity is not effective.

This new study involved 77 subjects randomly assigned to play 8 hours of Lumosity or Portal 2 (a popular video game). They found that the Portal 2 players outperformed the Lumosity players on all three cognitive evaluations: problem solving, spatial skills, and persistence. The only pre-test to post-test significant improvement was the Portal 2 group for spatial skills.

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Oct 21 2014

Graphene Neuro-electrode

This news item combines two technologies that I have been eagerly following, graphene and brain-machine interface. Researchers have developed a 1-molecule thick graphene electrode that is transparent and can be used for high-resolution electrophysiological recordings of brain cell activity.

Before I explain why this is such a cool advance, I will quickly review these technologies. Graphene is an allotrope of carbon – it is made of a single atom thick layer of carbon atoms arranged in a hexagonal sheet like chickenwire. This arrangement is very stable with strong bonds, making for a strong material. It is also flexible and has useful electrical properties. It can be manufactured as a sheet or rolled up into carbon nanotubes.

Graphene is an incredibly promising material that is likely to be the cornerstone of future electronics, promising small, efficient, and flexible components. It conducts both heat and electricity very efficiently and it is a semiconductor. “Doping” the graphene with other elements also has the potential to tweak its physical properties, expanding the number of applications.

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Oct 17 2014

Brain Activity in Vegetative Patients

Published by under Neuroscience

A vegetative state is a particular kind of coma in which patients appear to be awake but give no signs (by definition) of any awareness. They do not respond to their environment in any way or do anything purposeful. Some patients display a flicker of awareness, and they are categorized as minimally conscious.

Neuroscientists have been using the latest technology to look at brain function in vegetative subjects and comparing that function to healthy controls. In this way they hope to gain insight into the neurological correlates of consciousness – what brain activity is necessary for and responsible for conscious awareness. A new study, published in PLOS Computational Biology, replicates this research with interesting findings.

As with previous studies, the researchers found that the majority of vegetative patients had profound abnormalities of brain function compared to healthy controls. They found:

Here, we apply graph theory to compare key signatures of such networks in high-density electroencephalographic data from 32 patients with chronic disorders of consciousness, against normative data from healthy controls. Based on connectivity within canonical frequency bands, we found that patient networks had reduced local and global efficiency, and fewer hubs in the alpha band.

This means they measured the electrical activity of the brain and found that patients in a vegetative or minimally conscious state had decreased brain activity. A healthy brain has massive local and global networks of neurons exchanging information across the brain. The brains of patients with impaired consciousness had markedly reduced activity and fewer hubs of activity.

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Oct 09 2014

AWARE Results Finally Published – No Evidence of NDE

Back in May I participated in a debate for Intelligence Squared regarding “Death is not Final.” At the time I was updating myself on the published literature regarding alleged near death experiences or NDEs, and noticed that the AWARE study (AWAreness during REsuscitation) had been completed but the data not yet published. I was disappointed that I would not have these results available to me during the debate.

I had read about the study several years earlier. This is a prospective study of cardiac arrest patients to not only describe their NDEs when they occur, but to conduct a large prospective test looking for objective evidence of conscious awareness during resuscitation. The lead researcher, Sam Parnia, is a believer in NDEs, but designed a study theoretically capable of finding objective evidence.

The multi-center study involved placing an image in a location that was hidden from normal view but could be viewed by a person floating above their body during an NDE. This could be a way to objectively differentiate between the two leading hypotheses. Parnia and others believe that reports of NDEs represent actual awareness during cardiac arrest when the brain is not functioning. This, of course, would be compelling evidence for cognition separate from brain function.

I and most scientist favor the more mundane and likely explanation that memories of NDEs are formed at other times, when the brain is functioning, for example during the long recovery process. At least the memories themselves do not differential between these two hypotheses, and this explanation does not require inventing entirely new non-materialist phenomena.

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Sep 29 2014

How Our Brains Respond to Ambiguous Images

Published by under Neuroscience

A new study looks at how our brains respond to images of celebrities made ambiguous by morphing two images into one, such as the combination of Halle Berry and Angelina Jolie shown here. The question is – will our brains fire in a way that represents the details of the picture, or will they fire based upon how we perceive the picture?

The researchers were able to study subjects who had small electrodes placed on the surface of their brains for clinical purposes. Such electrodes are capable of detecting the firing of a single brain neuron. They showed the subjects pictures of two celebrities to see how their brains responded. Typically a single neuron, which encodes the memory of that particular celebrity, would fire. They then showed them a morphed picture and asked them to identify the celebrity.

When subjects recognized Halle Berry, for example, the single neuron that previously fired when viewing Halle Berry also fired.

This is an interesting, but not unexpected, result. How does this fit into our understanding of brain function?

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Sep 16 2014

The Genetics of the Schizophrenias

Published by under Neuroscience

A new study sheds further light on the genetic basis of the group of psychiatric disorders known collectively as schizophrenia. Further, the study (actually a collection of four studies) takes a new approach that might prove generally useful in associating genetic variation with disease risk, even beyond psychiatry.

Schizophrenia

In popular culture the term “schizophrenic” is often used to mean split personality or multiple personality, but this has never been the actual definition of the term. I’m not sure what the origin of this misconception is. The word “schizophrenia” does mean “split mind” but refers to mental illness characterized by disordered or delusional thinking. The “split” is between reality and mental function.

For at least several decades it has been clear that schizophrenia is not one discrete disorder, but rather it is a set of similar disorders. Symptoms include hallucinations, delusions (persistent false beliefs that do not have a cultural cause), impaired reality testing, bizarre thoughts and behaviors, often but not always paranoid in nature, a disconnection between thoughts and emotions, and lack of motivation or activity.

Part of the challenge of studying schizophrenia is that it is a clinically defined set of disorders, meaning that the category is based upon the signs and symptoms displayed, not any knowledge about underlying cause or biology. The brain, as you might suspect, is an incredibly complex organ with many interacting parts, and so there is likely to be a complex relationship between the underlying mechanisms of schizophrenia and the clinical manifestations.

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Aug 28 2014

Bt and Leukemia – Another Anti-GMO Myth

The headline of an article on the Organic Consumers Association proclaims, “New Study Links GMO Food To Leukemia.” The same article trumpets the thoroughly discredited Seralini study. The claim is not true, but is part of a pattern of behavior that is depressingly familiar.

The pattern is not unique to anti-GMO activism. In fact, it seems to be the default human behavior. We tend to search for information that supports our currently held views. The more passionate we are about those views, the more industrious we are in finding apparent support, even if it means twisting and distorting information.

I find myself doing this all the time – if a study or new piece of information directly opposes something I currently believe, then my mind immediately starts finding reasons to dismiss the information. I have the opposite reaction when the information confirms my current beliefs, I find reasons to accept it.

But then I consciously step back and try to take an objective look at the information. This is not always easy, and may involve specialized knowledge I don’t have. I then have to look to experts to see if there is a clear consensus opinion. In other words, I don’t just stick with my knee-jerk reaction to information. I go through a process of evaluation and critical analysis. My goal is to come to a valid conclusion, one that will hold up under critical assault, whatever that conclusion is. Meanwhile I have to remain open to the possibility that my conclusion is wrong or incomplete, that I missed something or made an error in my process.

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Aug 19 2014

The Reid Technique of Investigation

Published by under Neuroscience

If you like crime dramas, you have probably seen this countless times. The officer interrogating a suspect chums up to them, says they understand, and then offers them a face-saving version of guilt to which they can confess. It’s compelling drama.

What is being depicted is known as the Reid Technique, developed by John Reid in the 1950s. This technique remains popular, but is also highly controversial.

A recent study, however, claims 100% accuracy using the Reid technique to detect deception in 33 interviews. That is very impressive, but raises some red flags. The study also claims 97.8% accuracy is a second trial of experts interrogating suspects, and 93.6% accuracy when students viewed tapes of the interrogations in order to determine guilt.

The primary reason I don’t find the results compelling is that the psychological study may not be a good analog of real-life situations. The suspects were students who were participating in a fake psychological study and were cajoled into cheating by a confederate in order to obtain a monetary reward that was part of the fake study. The interviews were also fairly brief, 3-17 minutes.

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Aug 18 2014

Planned Obsolescence and Attribution Fallacy

Published by under Neuroscience

There are multiple threads to this story, all revolving around how we make sense of the data before us. Regular readers will likely not be surprised to hear that we tend to labor under a host of cognitive biases that lead us from an accurate interpretation.

This story starts with big data – a loose term referring to the access to massive amounts of data made possible by the internet, search engines, and social media. Google, for example, can track search terms in real time and look for trends. Tracking search terms related to the flu, for example turns out to be an accurate predictor of flu outbreaks.

Recently, Harvard University PhD student Laura Trucco searched through Google Trends and found that searches for “iPhone slow” tend to peak just before Apple is set to release a new model of iPhone. This led to speculation that perhaps Apple is deliberately gimping older models of the iPhone in order to motivate users into upgrading.

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Aug 08 2014

IBM’s Brain on a Chip

Well,  a small one, but it’s a start.

IBM announced that they have build a computer chip, dubbed TrueNorth, based on a neuronal architecture. The team published in Science:

Inspired by the brain’s structure, we have developed an efficient, scalable, and flexible non–von Neumann architecture that leverages contemporary silicon technology. To demonstrate, we built a 5.4-billion-transistor chip with 4096 neurosynaptic cores interconnected via an intrachip network that integrates 1 million programmable spiking neurons and 256 million configurable synapses. Chips can be tiled in two dimensions via an interchip communication interface, seamlessly scaling the architecture to a cortexlike sheet of arbitrary size. The architecture is well suited to many applications that use complex neural networks in real time, for example, multiobject detection and classification. With 400-pixel-by-240-pixel video input at 30 frames per second, the chip consumes 63 milliwatts.

Sounds pretty cool. I have written about brain-like computing previously (most recently here). Von-Neumann architecture refers to the traditional basic setup of modern computers, which were described in 1945 by (you guessed it) John von Neumann. This setup has three components: memory, communication, and processing. Information is binary, essentially ones and zeros.

The neuromorphic architecture combines these three elements into one. The neurons are the memory and the processing, and they communicate with each other, similar to a biological brain. Instead of binary code, the neurons spike with a certain frequency. When they send spikes to another neuron, they bring it closer to its threshold for spiking. This is very similar to how the brain functions.

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