Archive for the 'Neuroscience' Category

Dec 18 2014

Egnor Doubles Down on Incoherent Nonsense

Egnor continues his dualist neuroscience denial in two follow up posts, mostly responding to PZ Myers’ take down of his original post. Egnor has also been writing separately about computers, arguing that they have no memory and will never be intelligent (have agency).

In all of these posts Egnor is following the same basic intellectual strategies – use words in a vague and confusing way to befuddle your reader, and assume your conclusion (dualism). Ironically, he writes:

The contemporary criticism of such phrases as “memory is stored in the brain” and “the brain evaluates propositions” and “the occipital cortex perceives images” — criticism made by neuroscientists and philosophers like¬†Maxwell Bennett and Peter Hacker¬†among others — is in keeping with the salient critiques by ordinary language philosophers who insist that we need to be honest and careful with the meanings of words in our scientific discourse. Ordinary language philosophy in neuroscience is an appeal to conceptual hygiene.

The projection is truly amazing. Science denial is pseudoskepticism – all of the form with none of the actual substance.

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Dec 16 2014

Neurosurgeon Thinks the Brain Doesn’t Store Memories

It has been six years since I have written a blog post deconstructing the nonsense of our favorite creationist neurosurgeon, Michael Egnor. In case you have forgotten, he is a dualist writing for the intelligent design propaganda blog, Evolution News and Views. He delights in ridiculing what he calls “materialist metaphysics,” or what scientists call, “science.”

I guess I shouldn’t be surprised that he has managed to outdo his prior incoherent ramblings. In a recent blog post he claims that it is impossible for the brain to store memories, an idea he ridicules as “nonsense.”

As usual, Egnor is playing loose with definitions and logic, tying himself up in a conceptual knot in order to arrive at his desired destination – the idea that the brain cannot account for mental phenomena. His logic train derails pretty quickly:

It has been known for the better part of a century that certain structures in the brain are associated with memory. The amygdala and the hippocampus in the temporal lobe, and some adjacent cortical regions, have been shown to be associated with the act of remembering in animals and humans.

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Nov 10 2014

Feeling of Presence Induced in the Lab

I have investigated a few hauntings and ghostly phenomenon. In reality I was investigating the ghost-hunters who were investigating alleged hauntings. A few patterns quickly emerged. One is that actual sightings and reported events tended to cluster around a few individuals, or even one individual. Another is that such events never occurred when there was a skeptical investigator present.

Also very interesting, however, was that the real interesting stuff did not start happening until the early morning hours, such as 2 or 3 in the morning. Ghost hunters invent lore to explain this phenomenon (the haunting hours), but my hypothesis is that this is the perfect time for sleep deprivation to be taking its toll.

When the evidence for a phenomenon is reported subjective experience, we need to ask if those experiences are being generated by something happening outside the person, or just inside their brain. When the brain is sleep-deprived, it can become glitchy. We can fall asleep briefly without realizing it. We can start to slide into a dream state, and might even experience a fusion of the waking and dream state, even to the point of hallucinations.

One common report is the feeling of presence (FoP) – the sense that there is another entity in the room with us, although we can’t quite see it as it is lurking just at the edge of our vision. I have experienced this myself, during hypnagogic episodes when I am very sleep deprived.

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Oct 31 2014

Brain Size and Intelligence

Published by under Neuroscience

I was recently asked about the relationship between brain size and intelligence. This is a question I get every now and then, because the relationship is not an obvious one. In this particular case, the questioner was curious about the fact that Neanderthals had a larger cranial capacity on average than modern Homo sapiens.

For the sake of this discussion I am going to avoid a detailed treatment of the concept of “intelligence.” It’s important to note that intelligence is a multifaceted phenomenon, there is no single way to measure it, and it cannot be captured by any single number. Having said that, we can use various markers or measures of cognitive ability to loosely represent overall intelligence. Problem solving, for example, is one measure, and can be used in multiple species. I will come back to this later, for for the sake of this discussion I will be referring to intelligence as overall cognitive ability without getting specific.

Once scientists figured out that the brain is the seat of intelligence, we were quick to observe that humans had relatively large brains. This made sense – humans seem to be, by far, the most intelligent species on the planet, so it makes sense that we have the biggest brains.

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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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