Archive for the 'Neuroscience' Category

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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Jul 29 2014

Reward and Punishment in the Brain

Published by under Neuroscience

In a recent study, scientists looked at the brain with high resolution fMRI scanning while they showed subjects pictures. Following each picture was a painful electric shock, or a money reward, or no response, or a random response. Subjects quickly learned which pictures would be followed by which stimuli – positive, negative, neutral, or unpredictable.

Scientists do this sort of thing not because they like to torture people but to study the brain’s response. In this case they were particularly interested in a small deep structure called the habenula. What they found, for the first time in humans but consistent with prior animal research, is that the habenula would light up when subjects saw a picture that would be followed by a shock, and the activity in the habenula increased the more certain the subjects were that negative stimuli were following.

The researchers conclude that the habenula is a critical structure for the processing of negative stimuli, in fact it seems to be the hub of the neural network involved in learning to anticipate negative stimuli.

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Jul 24 2014

Sleep and False Memory

Published by under Neuroscience

When someone looks at me and earnestly says, “I know what I saw,” I am fond of replying, “No you don’t.” You have a distorted and constructed memory of a distorted and constructed perception, both of which are subservient to whatever narrative your brain is operating under.

One of the more dramatic aspects of memory distortion is false memories. These can be completely fabricated memories that are indistinguishable from genuine memories. False memories can involve small details, or entire scenarios. One way to fabricate false memories is with suggestion – just suggesting to someone a detail of an experience they had may cause them to incorporate that detail into their memory of the experience.

The apparent reason for this is that our brains appear to favor consistency over accuracy. Memories are updated to bring them into line with our current knowledge. If we are told that the person was wearing a blue jacket, then our memory might change so that it is consistent with what we now believe to be true.

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Jul 17 2014

European Commission Human Brain Project Hubbub

Published by under Neuroscience

In 2013 the European Commission awarded $1.3 billion to a project to simulate the human brain in a supercomputer. While everyone is excited about this prospect, and welcomes the infusion of cash, recently the project has come under public criticism.

More than 180 neuroscientists signed an open letter criticizing the way the project is being managed. The letter states:

“We believe the HBP is not a well-conceived or implemented project and that it is ill suited to be the centerpiece of European neuroscience.”

There appear to be two main points to the criticism – the first is that the money is largely going to computer scientists to create the software that will simulate the human brain. The neuroscientists complain that while the project is being sold to the public as a neuroscience project, in reality it is an IT project.

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Jun 17 2014

Deepak Challenge to Skeptics

Deepak Chopra doesn’t appear to like skeptics much, or understand them. He just put out a YouTube video challenging ”Randi and his cronies” to his own fake version of the million dollar challenge.

All we have to do, apparently, is make 50-100 years of scientific advance in neuroscience in a single peer-reviewed paper. I’ll get started on that right away.

Actually, even that probably would not be sufficient. The whole point of pseudoscientific goal-post moving is to keep forever out of reach of current scientific evidence. It doesn’t matter how much progress science makes, there will always be gaps and limitations to our knowledge. Chopra lives in the gaps.

Here is his exact challenge:

Dear Randi: Before you go around debunking the so-called “paranormal,” please explain the so-called “normal.” How does the electricity going into the brain become the experience of a three dimensional world in space and time. If you can explain that, then you get a million dollars from me. Explain and solve the hard problem of consciousness in a peer-reviewed journal, offer a theory that is falsifiable, and you get the prize.

The challenge is absurd because it is completely undefined. “Explain” to what degree? Science often advances by developing theories that are progressively deeper. Obviously we can explain consciousness on some level, and just as obviously Chopra would not accept that level as sufficient, but he gives absolutely no indication of how much deeper an explanation he would require.

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Jun 06 2014

PETA Responds

Last week on Science-Based Medicine I wrote an article about the embrace by PETA (people for the ethical treatment of animals) of pseudoscience – in this case they are engaging in a fearmongering campaign linking dairy products to the risk of autism or increasing the severity of autism.

Yesterday I received an e-mail from PETA, essentially doubling down on their prior embrace of pseudoscience:

Dear Steven,

I want to follow up on your story last week about PETA’s campaign that points out how a dairy-free diet may help children with autism. PETA’s website and campaign serve to provide parents with potentially valuable information, albeit mostly anecdotal, from families’ findings—for example, just this week, the editor of Autism Eye magazine, Gillian Loughran, who has a 14-year-old son with autism, contacted us in support of our campaign and wrote a letter to the editor on our behalf (see below). Until such time as there is a large study into whether there is a dairy-autism link (and one we hope will not be funded by the dairy industry), it seems unwise to overlook a growing body of anecdotal information supporting that removing dairy and gluten from the diet of a child with autism may improve the child’s sleep, behavior, and concentration. We hope this letter will change your mind about PETA’s campaign—or, at least, that you will share this letter with your readers so that they can arrive at an informed opinion.

Thank you for your time.

Best regards,

Heather 

There are multiple problems with this position.

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Jun 05 2014

Preventing Memory Impairment

Published by under Neuroscience

One of the more common complaints I see in my clinical practice is subjective memory impairment (SMI) – the perception of poor concentration and short term memory. SMI is distinguished from full-blown dementia in that the mental status exam and diagnostic tests are normal, but the symptoms can still be significant.

Once an underlying disease or specific pathology has been ruled out, the working diagnosis for SMI is that it is functional, meaning that it is a symptom of some process that is temporarily impairing brain function but not causing permanent or progressive brain damage. The task then becomes to identify any lifestyle factors that may be causing SMI.

A recent study published in PLOS One sheds further light on such risk factors. The authors conducted a survey of 18, 614 people of various ages and asked questions about memory and behaviors. They found:

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May 27 2014

The Brain Is Not a Receiver

Whenever the discussion of a dualist vs materialist model of the mind comes up, one common point made to support the dualist position (that the mind is something other than or more than just the functioning of the brain) is that the brain may not be the origin of the mind, but rather is just the receiver. Often an explicit comparison is made to radios or televisions.

The brain as receiver hypothesis, however, is wholly inadequate to explain the relationship between the brain and the mind, as I will explain below.

As an example of the brain-receiver argument, David Eagleman writes in his book Incognito:

As an example, I’ll mention what I’ll call the “radio theory” of brains. Imagine that you are a Kalahari Bushman and that you stumble upon a transistor radio in the sand. You might pick it up, twiddle the knobs, and suddenly, to your surprise, hear voices streaming out of this strange little box. If you’re curious and scientifically minded, you might try to understand what is going on. You might pry off the back cover to discover a little nest of wires. Now let’s say you begin a careful, scientific study of what causes the voices. You notice that each time you pull out the green wire, the voices stop. When you put the wire back on its contact, the voices begin again. The same goes for the red wire. Yanking out the black wire causes the voices to get garbled, and removing the yellow wire reduces the volume to a whisper. You step carefully through all the combinations, and you come to a clear conclusion: the voices depend entirely on the integrity of the circuitry. Change the circuitry and you damage the voices.

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