Category: Inside the Brain

A new paper in PLoS Computational Biology by Quan Wen and Dmitri Chklovskii reports on a computer model that would naturally separate into grey and white matter if asked to produce the optimum design for a brain that needs high interconnectivity and short conduction delays.

Computational models are often good ways of developing theories, and this research might help explain the purpose and role of the different cell types in the brain.

Unfortunately, my maths isn’t good enough to grasp the mechanics, but there’s some fascinating reading in there nonetheless. Published as an open access article. Share the computational biology love.

Link to ‘Segregation of the Brain into Gray and White Matter: A Design Minimizing Conduction Delays’.
Link to PLoS Computational Biology.

A letter in today’s Nature from neuroscientist Kenneth Kosik makes an interesting point about the possible theological implications of neuroscience and suggests that it may become a new battleground in the ongoing tussles between scientific theory and religious fundamentalism:

The argument over evolution versus intelligent design, discussed in your News story “Day of judgement for intelligent design”, is a relatively small-stakes theological issue compared with the potential eruption in neuroscience over the material nature of the mind.

Siding with evolution does not really pose a serious problem for many deeply religious people, because one can easily accept evolution without doubting the existence of a non-material being. On the other hand, the truly radical and still maturing view in the neuroscience community that the mind is entirely the product of the brain presents the ultimate challenge to nearly all religions.

Link to full text of letter.

PsyBlog has picked up on a recent article in The Independent that discusses the debate over cannabis and the risk of developing psychosis. This is currently topical in the UK in light of an expected government report about the legal re-classification of the drug.

Previously, it was known that there is an association between cannabis and psychosis, although it was not clear whether cannabis contributed to psychosis, or whether people with psychosis were simply more likely to ‘self-medicate’ with cannabis in an attempt to feel better.

A 2004 article in the British Journal of Psychiatry reviewed studies which allow a causal link, rather than simply an association, to be inferred, and sparked a debate (see PubMed entry) which has now led the goverment to think again about the recent downgrading of the legal penalties for possessing cannabis.

Although many psychiatrists and researchers now believe that cannabis is a causal factor in psychosis, the effect is still thought to be small in most people. Genetic studies have reported, however, that people holding certain versions of the COMT gene may be more likely to develop psychosis when cannabis is used.

Nevertheless, an alternative debate centres on whether public education and health services benefit for such a widely used drug to be outlawed, when other, potentially more harmful substances, are legally sold.

Link to Independent article ‘Cannabis: Can it really drive you mad?’
Link to PubMed entry of 2004 debate in the BJP (link to free full text articles).

ABC Radio’s Health Report has a special on stroke – where the blood supply is cut off by damage or obstruction to blood vessels in the brain – and interviews two survivors about their experiences: Robert McCrumb, the literary editor of The Observer newspaper and Ishbel, a 9 year old girl who suffered a stroke when she was 7.

The stroke survivors describe the immediate effects, the treatment, the aftermath and their own tips for coping with stroke-related brain injury.

Robert McCrumb wrote a book about his experiences called My Year Off (ISBN 0330352407), and wrote an insightful article for The Observer marking ten years since it first occurred.

The programme also talks to Roger Rees, a professor of disability research, who talks about the impact of the disorder on the mind and brain, and medical approaches to recovery.

mp3 or realaudio of programme audio.
Link to programme transcript.
Link to Robert McCrumb’s article ‘Memoirs of a survivor’.
Link to ‘What is a stroke?’ from the Stroke Association.

There’s a raft of new articles just appeared on Science and Consciousness Review, including a speculative but fascinating article on information states in the brain and consciousness.

The article by Henri Montandon discusses the ideas and implications of researcher Giulio Tononi who argues that an entity is more conscious the more information it can bring to bear on life experiences.

There’s plenty more news stories just been added as well, so have a wander through and enjoy.

Link to Science and Consciousness Review.

Neuroscience, the investigation of brains, is a child of the Enlightenment, born of the belief that nothing is out of bounds to science. Like her sister, genetics, she grew up in the twentieth century, overshadowed by their older sibling physics, who has changed all our lives and has blood on her alter to prove it. Genetics promises even greater accomplishments, boasting of how she will one-day conquer the world. Compared to these shadowy teenagers, neuroscience is a quiet Cinderella. But some say that she will outstrip her sisters, changing not only the world we live in, not only the bodies we are born with, but the thoughts and selves and cultures we create.

Stirring words from physiologist Kathleen Taylor in her fascinating book on the history and science of ‘Brainwashing‘ (p105, ISBN 0192804960).

Link to previous post on Brainwashing.

“We know that we are agents and that we are successfully causing the world to change. But as actors we move through the world like shadows glimpsed only occasionally from the corner of an eye.”

From a recently published paper by neuropsychologist Chris Frith on the links between the neuroscience of action and delusions of control.

Link to abstract of Frith paper.

The New York Times has a short piece on Peter Whybrow’s and John Gartner’s theory that Americans have a greater genetic propensity for hypomania, the elevated mood state sometimes found in bipolar disorder.

This, they suggest, explains aspects of American culture such as focus on energetic enthusiasm and respect for new ideas.

Interestingly, recent genetic evidence is now pointing to the fact that genes likely to be present in people diagnosed with schizophrenia overlap with those found in people diagnosed with bipolar disorder, suggesting that these may not be distinct disorders, but exist on a continuum.

If Whybrow and Gartner are right, therefore, might Americans be more likely to show traits of psychosis and schizotypy as well?

This may not necessarily be a bad thing, as high levels of these traits have been linked to greater mathematical ability and creativity.

Link to article ‘The Hypomanic American’.

There’s no credible motive but in 1903 that doesn’t matter, the prosecuting barrister can always blind the jury with a little bit of brain:

Like you, members of the jury, I have at different moments of the trial, convinced as I am and as you will be of the prisoner’s guilt, I have found myself asking, but why, but why? And this is what I would say to that question. It really does seem to point to a person who did these outrages from some diabolical cunning in the corner of his brain.

From Arthur and George by Julian Barnes. Jonathan Cape: London, 2005.

Author Nicola Morgan has written a book on neuroscience for teenagers, that explains why teenage experience and behaviour seems so intensely different during adolescence.

The book, Blame My Brain, manages to accurately present scientific research, without presenting any ‘just so’ stories. Various theories and approaches are given where a strong conclusion is not widely accepted.

It also manages to explain neuroscience in a straightforward yet engaging way:

For a long time, people have assumed that this inability to get out of bed is just teenagers being lazy. We have blamed it on the fact that they choose to stay up too late and therefore can’t get up in the morning. But new research shows that laziness and deliberately late nights are not entirely to blame.

…

When the body clock switches off, it tells our bodies to start feeling sleepy, and the brain produces a hormone called melatonin. This chemical prepares our brains to be sleepy. Tests have shown that in adolescence, melatonin is produced much later in the evening than in younger children. About the same as adults in fact. This is why you don’t often feel sleepy until late in the evening.

It also includes plenty of tests and demonstrations that the reader can try out on themselves or their friends and family!

Link to details of Blame My Brain: The amazing teenage brain revealed.

New Scientist reports on a recent study that examines the effect of coffee on the brain. The good news is that it seems to do the frontal lobes, and the executive system, the world of good.

“The group all showed activation of the working memory part of the brain,” Koppelst√§tter explains. “But those who received caffeine had significantly greater activation in parts of the prefrontal lobe, known as the anterior cingulate and the anterior cingulate gyrus. These areas are involved in ‘executive memory’, attention, concentration, planning and monitoring.”

Just don’t mention the withdrawal headaches…

Link to article ‘Coffee’s effects revealed in brain scans’.

Poor sleep is the common result of stress or illness, but sleep researchers are increasingly coming to believe that insomnia itself is a separate disorder. Science News discusses the science of insomnia, and new developments in the neuroscience of ‘sleeping pills’.

One problem with previous types of sleeping pill (particularly the benzodiazepines) is that they become quickly addictive and so are indicated for short-term use only. The holy grail of sleep medication research is to find a compound which is non-addictive and not ‘fun’ enough to be abused.

Science News reviews various compounds that are new or currently in development, and their aim to safely mimic earlier medications, or hormones in the body that promote sleep.

For people who are having trouble sleeping, however, there are simple techniques which can significantly improve sleep time and quality.

The Sleep Disorders Center at the University of Maryland Medical Center has some online advice to help people manage their sleeping environment and habits to get the maximum benefit out of sleep.

Link to Science News article ‘Staring into the dark’.
Link to ‘Helpful Hints to Help You Sleep’.

If using vibrators to shrink your waistline makes you think of spam email, you may be surprised to find out it’s the basis of a fascinating neuroscience experiment published in open-access science journal PLoS Biology.

The study relies on an unusual effect called the Pinocchio illusion, which occurs when a vibrating sensation is applied to the outside muscle on one of the body’s joints. This causes a feeling of the joint closing, when in fact it remains in the same position.

This feeling of movement can conflict with other bodily sensations, and can produce the unusual feeling that body parts are becoming warped or elongated, just like Pinocchio’s nose.

In Ehrsson’s experiment, they applied a vibrating sensation (the blue boxes in the diagram) to the back of each wrist, which gave the false impression that the hands were moving in towards the legs.

While this was happening, Ehrsson and his team brain-scanned the participants to detect active brain areas, and compared conditions where participants were touching vs not touching their legs; and where the vibration was applied to the joint muscles vs another area on the hands.

Crucially, only in the condition when the participant’s hands were touching their legs and the wrist joint muscles were being vibrated, did it feel as if their waste was shrinking to accommodate the illusory movement.

The team found that the strength of the illusion was associated with activity in areas of the left parietal lobe, which are known to be involved in creating the sensation of body shape, also called ‘body image’.

The study suggests that the brain generates body image by making a best guess from the incoming tactile information.

In other words, because the wrist jounts were providing ‘false’ information – indicating that the hands were moving through space occupied by the legs – the brain simply ‘guessed’ that the waist must be smaller to make sense of the discrepancy.

If you want to try this effect at home, a couple of vibrating sex toys are probably your best bet. If you don’t have any, now’s your chance to freak out your local sex shop by asking them to recommend the best dildo for cognitive neuroscience experiments.

Link to study summary.
Link to full text paper.
Link to write-up from nature.com
Link to write-up from BBC News.

ABC Radio’s All in the Mind starts a four part series today on the emotional brain, with the first in the series examining the complexity of sexual desire.

Psychologists Dylan Evans and Doris McIlwain discuss whether we have one sex drive or many, and how it influences and gets tangled up with our other thoughts, desires and behaviour.

Despite the portrayal in some of the media, what emerges is that sexual desire is a rich and complex human motivator.

mp3 or realaudio or programme audio.
Link to transcript.

The New York Times has an article on the increasing interest in hypnosis among cognitive neuroscientists, who are trying to understanding how suggestion and belief can affect basic mental processing.

The article describes some interesting recent work on hypnosis and perception, but omits some of the most fascinating experiments in this area.

A study published in 2003 involved hypnotising participants to simulate experiences of external control, akin to experiences sometimes found in psychosis, to discover whether similar brain areas might be involved in the psychotic and non-psychotic experiences.

Another study, published in the same year, involved hypnotising participants so they thought they were paralysed, in an attempt to better understand ‘hysterical’ paralysis, sometimes known as conversion disorder – a condition where paralysis is thought to occur due to psychological trauma rather than physical damage.

In these cases, hypnotised, non-hypnotised or ‘pretending’ participants were were asked to conduct actions while being brain-scanned, to compare and contrast active brain areas.

Interestingly, these two studies suggested that quite different brain networks were involved in producing the experiences, although both activated the cerebellum, a complex area, known to be involved in movement, but still largely mysterious.

Link to article ‘This Is Your Brain Under Hypnosis’.

As a follow up to our previous post on the history of the now discarded practice of lobotomy, there’s been quite a bit of recent interest in the science and ethics of modern-day brain surgery in treating mental illness, a practice often known as ‘psychosurgery’.

BBC Radio 4 aired a one-off documentary called Brain Surgery to Cure the Mind, that discussed its history, practise and effects, including the use of ‘deep brain stimulation or DBS.

DBS involves implanting an electrode to increase or decrease activation in a certain brain area. It was pioneered for the treatment of Parkinson’s disease but early results suggest it may be useful in treating severe clinical depression. One advantage of DBS over other types of neurosurgery is that it is reversible.

An alternative type of brain surgery, used in both severe psychiatric illness and Parkinson’s disease, is to sever or remove a small area of brain thought to be involved in the causing the distress or impairment.

This latter form is particularly controversial, and the British Journal of Psychiatry has published a debate entitled ‘Should neurosurgery for mental disorder be allowed to die out?’.

A recent review of the scientific literature, based on psychiatric neurosurgery in Scotland details the evidence for the effectiveness of such treatments, what the most common forms of brain surgery involve, and the likely physical and cognitive risks.

Link to BBC ‘Brain Surgery to Cure the Mind’ (with audio).
Link to debate ‘Should neurosurgery for mental disorder be allowed to die out?’.
Link to article ‘Status of neurosurgery for mental disorder in Scotland’.