Archive for August, 2011

Aug 08 2011

How Mammalian Brains Map in 3D

Published by under Neuroscience

Remember that famous scene from Star Trek II – Kirk and Khan are engaged in a classic submarine-style fight in a large gas cloud. Spock has analyzed Khan’s tactics and deduced that while Khan is genetically engineered to be brilliant, he is inexperienced. “He’s thinking two-dimensionally,” concludes Spock. Next we see the Enterprise rise up out of the depths of the cloud (relatively speaking) and get a sneak attack on Khan’s ship from behind.

While very dramatic, I always wondered how realistic that scene was. Is there a naive tendency to think two-dimensionally, even when flying out in space? Well, new evidence suggests that perhaps there is.

Neuroscientists have published a study in rats in which they look at the activation of two specialized types of neurons, grid cells and place cells, in rat brains as they navigate a three-dimensional space.

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Aug 05 2011

The Motivated Reasoning of Egnorance

Published by under Neuroscience

If you want to see many examples of motivated reasoning, pay a visit to Michael Egnor’s blog, Egnorance. He’s the evolution-denying neurosurgeon that I have sparred with over the last few years, mostly about evolution and dualism. Motivated reasoning is what most people do most of the time – start with a desired conclusion and then find reasons to support it (humans are very good at that). However, the whole point of philosophy is to rise above this tendency and follow strict rules of logic, while the point of science is similar but also to follow the evidence. Egnor can’t seem to do either, as he rants against non-believers, misinterprets study after study, and attacks those who do not share his particular faith.

A few weeks ago he wrote a response to a blog post of mine about materialism. This is familiar ground, but he does nicely reveal his tactics in the article so I thought I should eventually respond. He starts by misrepresenting the very topic of the discussion:

He put together six assertions that he claims are proven scientifically and thus prove his theory that the mind is caused entirely by the brain.

The materialist theory of mind is not my theory – it is the overwhelming consensus of neuroscientists and the result of over a century of research. But Egnor would have his readers believe it is my own quirky “bizarre” theory. This is, of course, nonsense. It is Egnor who is out on the fringe of neuroscience with his antiquated dualist beliefs. But far more important are the actual arguments themselves (I make this point mainly to demonstrate how Egnor constantly rewrites reality).

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Aug 04 2011

The Mind is Faster than the Foot

You’re driving down the road when the car in front of you suddenly slams on the breaks. You see their break lights go on followed by the car rapidly getting closer to you and filling your visual field. Your brain registers what is happening and immediately plans a motor response in reaction – take your foot off the gas and apply pressure to the brake. Your car then screeches to a halt – but will it stop quickly enough to avoid colliding with the car in front of you?

A recent study looks at the ability to predict when a driver is about to brake in an emergency breaking situation. They used a driving simulator and monitored the gas pedal, the brake, the muscle activity in the subjects’ legs (EMG), the speed of the car, the distance to the car in front, and the EEG activity (electrical brain activity) of the driver. What they found is not surprising, but quantifies the time intervals involved.

The EEG reveals that the visual stimulus is recognized first, followed by the intention to perform a motor action (240 ms – miliseconds). Then the motor action begins (335 ms), resulting in stopping the gas (430 ms) and then applying pressure to the brake (595 ms). There is actually a range of figures for each event, based upon the accuracy of prediction. The longer you wait, and the more data you gather, the higher the accuracy. Predictive accuracy of >95% was generally achievable using information from EMG and EEG. To boil it all down, the authors estimate that a system using EMG and EEG can predict a driver’s intention to brake in an emergency setting 130 ms prior to when they would actually brake. This potentially could result in a 3.66 meter shorter breaking distance, which can mean the difference between a crash and near miss in many cases.

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Aug 02 2011

The Neuroscience Approach to Weight Control

The obesity debate rages on. I have covered this topic quite a bit on this blog – what factors contribute to overweight and obesity and what strategies are effective in maintaining a desired weight?

The outlook is fairly grim from the perspective that there are no easy answers or guaranteed techniques (from an intention to treat analysis). About 95% of all people who try to lose weight fail long term. Various diet revolutions (low fat, low carb, and an endless sequence of fad diets) have failed to produce results. Meanwhile, overweight and obesity in the industrialized world continues to rise.

Now a group of neuroscientists (Bradley M. Appelhans PhD, Matthew C. Whited PhD, Kristin L. Schneider PhD and Sherry L. Pagoto PhD) have weighed in on the debate in an article titled: Time to Abandon the Notion of Personal Choice in Dietary Counseling for Obesity? Not surprisingly, they take a neuroscientific perspective on weight control.

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Aug 01 2011

Don’t Shoot the Skeptical Messenger

Published by under Skepticism

Many of the popular science bloggers are decidedly skeptical in their outlook, choosing to promote critical thinking in addition to factual knowledge about their field of expertise. This is a good thing, and I certainly count myself among them. Many of those bloggers embrace the word “skeptic,” meaning scientific skepticism – the rigorous application of logic and evidence to all claims, with a healthy appreciation for the myriad mechanisms of self-deception to which humans are vulnerable.

One of the primary goals of blogging about science and skepticism is to engage the public and other professionals in discussions of important science issues of the day. We welcome criticism, as long as it engages with the logic and evidence.

Increasingly, however, I see those who find themselves at the pointy end of our skeptical jabs responding with what amounts to ad hominem attacks (focusing on us personally rather than our arguments). They have attacked us personally, impugned our motives, accused us of fictitious conflicts of interest, questioned the appropriateness of spending time writing to the public, and have tried very hard to characterize us as closed-minded cynics. Sometimes the attacks are so childish they are beneath recognition or response. But often the attacks are more subtle and sophisticated – but they represent the ad hominem logical fallacy none-the-less.

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