Optimal excitability

Nobel prize-winning psychologist Ivan Pavlov (1849-1936) gives a description of brain activity that eerily echoes the results of modern brain scanning studies.

The quote is from a lecture given in 1913 and published on p222 of the book Lectures on Conditioned Reflexes: Twenty-Five Years of Objective Study of the Higher Nervous Activity Behavior of Animals.

“If we could look through the skull into the brain of a consciously thinking person, and if the place of optimal excitability were luminous, then we should see playing over the cerebral surface, a bright spot with fantastic, waving borders constantly fluctuating in size and form, surrounded by a darkness more or less deep, covering the rest of the hemisphere.”

Hand in Glove

And who could resist finishing the day with rock n’ roll?

Seed magazine has an account of rock producer turned cognitive neuroscientist Dan Levitin meeting with rock musician David Byrne, and 3QuarksDaily have found a curious reference to 80s group The Smiths in a book on the philosophy of mind.

The first paragraph of philosopher Akeel Bilgrami’s book Belief and Meaning (ISBN 0631196773) contains a reference to The Smiths track ‘Bigmouth Strikes Again’:

Content is what is specified by sentences or propositions in that-clauses when we attribute intentional states to agents. Thus, in the attribution, “Smith believes that Bigmouth has struck again,” the sentence or proposition (Bigmouth has struck again) which follows the “that” specifies the content.

Link to Dan Levitin and David Byrne interview in Seed.
Link to 3QuarksDaily on philosophy and The Smiths.

Marijuana and the causes of madness

Huge numbers of news sources are reporting on recent neuroscience studies that have linked the effect of cannabis on the brain to the development of psychosis.

The excitement is because the 2nd International Cannabis and Mental Health Conference is currently under way in London where scientists from around the world are presenting the latest research on the effects of cannabis.

Luckily, the conference programme and summaries for all the research presented are available online as a pdf file, so you can get a more accurate idea of what the studies have found.

It is now clear that cannabis increases the risk of psychosis in some people who have a family history of psychosis and / or certain versions of the COMT gene.

However, the main thrust of the news stories is that even a single dose of THC, the main ingredient in cannabis that causes the ‘high’, can trigger psychotic symptoms.

A study by Dr Cyril D’Souza noted that:

Δ-9-THC produced schizophrenia-like positive and negative symptoms, altered perception, increased anxiety, produced euphoria, disrupted immediate and delayed word recall, impaired performance on tests of attention and working memory without impairing orientation.

The difficulty is that just because something seems to cause similar effects to psychosis, it doesn’t necessarily mean it is strongly linked to it.

For example, a dose of alcohol can ‘produce’ similar symptoms to Alzheimer’s disease – loss of memory, disorientation, mood swings, aggression and so on – but that isn’t a good basis to say that the alcohol is doing the same thing in the short-term as the degenerative brain disorder does in the long-term.

More convincing are the results from the cognitive tests: impairment in immediate and delayed recall, attention and working memory without impairing orientation.

This is because the subjective effects of both cannabis and psychosis are, well subjective, but the cognitive effects are measurable with controlled neuropsychological tests.

One particularly interesting study from Dr Cecile Henquet found that when compared to controls, patients experienced a greater increase in psychotic experience after taking THC, but also had a greater improvement in their mood.

This might explain why people with psychosis will often continue smoking cannabis even when they know it causes their mental state to deteriorate.

Another fascinating finding, is that as well as containing the possibly psychosis increasing THC, cannabis also seems to contain an antipsychotic called cannabidiol or CBD.

One study presented by Prof Markus Leweke found that purified CBD had a beneficial effect equal to amisulpride, a widely used pharmaceutical antipsychotic medication.

If you’re interested in finding out more about the cutting-edge of cannabis research the surprisingly readable conference programme is well worth checking out.

Link to conference programme and research summaries.

Does sex on first date boost relationship chances?

Dr Petra Boyton casts a critical eye on recent media stories suggesting that sex on first date releases ‘brain hormones’ that increase trust and intimacy that might improve the long-term chances of a relationship. So what does neuroscience tell us about the link?

The claim is made by Dr Barry Gibb [insert Bee Gees joke here] in a new book The Rough Guide to the Brain.

The claim is likely based on the fact that the hormone oxytocin has been reported to increase trust in humans when deliberately administered by experimenters, and has been linked to sexual response in humans.

The trouble is, the evidence for a strong and consistent link with sexual response isn’t really there yet.

A recent review article examined the role of hormones in sexual arousal and looked specifically at oxytocin, noting that:

Carmichael et al. (1987) found that plasma OT [oxytocin] increased around the time of orgasm in men and women, remaining raised for at least 5 min after orgasm…. In a recent study of men, OT increased in some subjects following ejaculation, but the individual variability was such that the group effect was not significant (Kruger et al. 2003a).

Murphy et al. (1987) reported an increase in OT in men during sexual arousal, which persisted beyond ejaculation, but with no obvious increase at ejaculation. In a study of women, Blaicher et al.(1999) found an increase in OT 1 min after orgasm, but levels were close to baseline by 5 min post-orgasm.

It is difficult to draw clear conclusions from this literature on OT and sexual arousal. Whether the increase of OT around orgasm, which has been somewhat inconsistently observed in the human literature, has any specific function, rather than being an epiphenomenon of other changes, remains uncertain…

In other words, the evidence for oxytocin being released consistently during sex is mixed and its significance is unclear.

Even if sex and the oxytocin ‘trust boost’ was reliably linked, you would need to do a study looking at whether couples trust each other more after having sex for the first time to really be sure whether the effect actually had an impact.

Sex causes such a strong behavioural, psychological and neurochemical change that a small release of oxytocin might be completely insignificant among the storm of other effects.

So does sex on first date increase the chances of a long-term relationship?

We don’t know, and what we do know about the neuroscience of sexual response doesn’t really tell us either.

UPDATE: Susan Kuchinskas has added some insightful commentary to this post. Check the comments section.

Link to Dr Petra Boyton’s article.
Link to full text of scientific article ‘The endocrinology of sexual arousal’.

An owner’s manual for the brain

So when did Discover magazine get so good? They’ve got an excellent ‘Mind and Brain’ section with a long list of feature articles freely available online.

Actually, what I wanted to feature was a one off magazine called ‘Discover presents The Brain: An Owner’s Manual’, which I found on the shelves of my local newsagent.

It’s labelled ‘Spring 07’, so is obviously current, but I can’t find anything about it on Discover’s website.

Check it out if you get the chance though. It’s solely dedicated to psychology and neuroscience and has some fantastic articles, but also includes some beautiful photos of intricate brain structures and has some neuropsychological tests to try.

Also, there are interviews with psychologist, author and diagnosed bipolar patient Kay Redfield Jamison, and Nobel prize-winning biologist and consciousness researcher Gerald Edelman.

Why this special issue isn’t mentioned on their website is something of a mystery though.

Link to Discover magazine ‘Mind and Brain’ section.

Getting emotional about cognitive science

The Boston Globe has a well-researched article on how emotion has become increasingly important in scientific models of the mind.

Only two decades ago, cognitive psychology rarely discussed emotion and was largely about the supposedly ‘cold’ computational aspects of mind: memory, attention, problem solving, language and so on.

It is now being recognised that emotion plays an important role in all of these aspects of mental life, largely because of developments in neuroscience.

This new science of emotion has brought a new conception of what it means to think, and, in some sense, a rediscovery of the unconscious. In the five decades since the cognitive revolution began, scientists have developed ways of measuring the brain that could not have been imagined at the time. Researchers can make maps of the brain at work, and literally monitor emotions as they unfold, measuring the interplay of feeling and thinking in colorful snapshots. Although we aren’t aware of this mental activity — much of it occurs unconsciously — it plays a crucial role in governing all aspects of thought. The black box of the mind has been flung wide open.

As an aside, the author of the piece is science writer Jonah Lehrer, who also writes neuroscience blog Frontal Cortex.

Link to Boston Globe article ‘Hearts and Minds’.

Science of hypnosis

Hypnosis and Suggestion is a fantastic website created by Dr Matt Whalley, an academic hypnosis researcher who gives a level-headed and detailed account of what is known about the science of hypnotic states and suggestion.

Hypnosis is a well researched psychological phenomenon and, increasingly, it is being investigated by cognitive neuroscientists.

What we know is that some people are more susceptible to hypnotic suggestions than others.

Research has shown that the level of hypnotic susceptibility is known to be stable across the life span and related to genetics.

A twin study shown that hypnotisability is likely to be heritable and recent molecular genetics studies have shown that it may be influenced by a gene known as COMT.

Interest has recently begin to focus on what makes some people highly hypnotisable compared to others.

A recent study looking at brain structure found that the front part of the corpus callosum was almost a third bigger in highly hypnotisable people.

This matches up with other neuroimaging studies which have suggested that highly hypnotisable people show differences in the function of frontal lobes, particularly the anterior cingulate cortex.

These differences are likely to be linked to an ability to become very ‘absorbed’ in things, with a simultaneous reduction in conflict and distraction when highly focused.

This might explain why hypnotic suggestions seem to have their effect on highly hypnotisable people, as they become absorbed in what the hypnotist says and can voluntarily ‘switch off’ the need to constantly self-monitor and evaluate their own reactions.

Interestingly, research suggests that we aren’t very good at working out how hypnotisable we are.

Matt Whalley’s site is a fantastic introduction to what is known about the science of hypnosis, including a list of frequently asked questions, an overview of the current theories of hypnosis, its history and its use by legitmate clinicians.

A fascinating read and well worth investigating if you’re curious about this intriguing human phenomenon.

Link to Hypnosis and Suggestion website.

Emotion research needs you

Jeremy Dean is the author of PsyBlog and also a postgraduate psychology researcher. He’s asking for people to spend 15 minutes completing some online questionnaires as part of a study on emotion.

The project is based at University College London but you can participate over the web.

There’s more information at the link below.

Link to Jeremy Dean’s emotion study.

Mouse-sized neural network created

Despite what the headlines might say, no-one has simulated a mouse brain. What has been created is still quite impressive though.

Scientists from IBM have created an artificial neural network which contains the simulated equivalent of the number of neurons in an actual mouse cortex, but with less synapses.

The mouse cortex contains about 8 million neurons, each of which has an average of 8,000 synaptic connections.

The simulation used the same number of ‘neurons’, but used an average of only 6,300 synaptic connections per brain cell, and each neuron fires about ten times slower than in real life.

Crucially, the simulated neurons are only vague approximations of the actual thing.

This is no reflection on the researchers, but really a result of the fact that we just don’t know enough about how single neurons work to create truly accurate simulations.

Also, the model was made up of simulated neurons of one particular type only to make things a little more straightforward.

Finally, there was no attempt to recreate the ‘architecture’ of the mouse cortex – that is, the division of the model into sections which do different functions, and no attempt to account for the function of non-neuronal brain cells.

The sheer scale of the model is impressive though, and shows that these large scale models are becoming technically feasible.

Previously, the technical restrictions of dealing with the computations and moving the data about quickly enough had not been overcome for a simulation of this size.

The project was run on a BlueGene/L supercomputer to make it possible.

IBM have released a short technical report on the project which is available at the link below.

pdf of report ‘Towards Real-Time Mouse Scale Cortical Simulations’.
Link to Wikipedia page on artificial neural networks.

Golden Guide to Hallucinogenic Plants

Online psychedelic drug archive Erowid has scanned in a copy of a classic guide to hallucinogenic plants of the world and how they are used by native peoples.

The Golden Guide to Hallucinogenic Plants is by pioneering ethnobotanist, Richard E. Schultes.

Ethnobotany is the study of how people make use of plants, and hallucinogenic plants are obviously of keen interest owing to their important place in ritual and religion throughout the world.

The book is sadly out of print and and second hand copies are now collectors items. However, the full version has been scanned in full colour, so you can read it online or download it as one single zip file.

Link to Golden Guide to Hallucinogenic Plants (via BB).

You are not your brain scan!

ABC Radio National’s All in the Mind just broadcast some essential listening with a programme that takes a critical look at the reporting of brain scanning studies and discusses what brain scans actually tell us about human nature.

The panel discussion also covers how cognitive and neuroscience discoveries get translated from lab work to public awareness, and how the core messages might get warped along the way.

The panel members are researchers and science journalists Deborah Blum and Jonica Newby, as well as neuroscientist Fred Mendelsohn.

It’s a rare but important discussion that actually takes a look at how brain scans are used in the media compared to what they actually tell us.

Link to All in the Mind brain scan programme webpage with transcript.
mp3 of programme audio.

Examining the brains of the dead to tackle dementia

The Washington Post has a fascinating article on the work of neuropathologist Dr Bennet Omalu (pictured right) who is researching whether American footballers are more likely to get dementia by examining their brains – after they’ve died.

The technique itself isn’t particularly controversial as the post-mortem study of brain tissue is one of the mainstays of neuroscience research.

It is difficult work, however, as it often involves asking the relatives at the point of death whether the body of their loved one can be examined for medical research, usually involving removing parts and examining them under a microscope.

Omalu thinks that the blows to the head suffered during Americfan football may increase the risk for early onset dementia and claims to have found tell-tale signs in the brain.

The idea that persistent low level head injury might raised the risk of dementia is not particularly new.

There are even some research findings suggesting that late life brain function is worse in ex-footballers and the risk for dementia may indeed by higher.

The Washington Post article is an interesting insight into an essential but difficult type of neurological research.

Link to Washington Post article ‘Brain Chaser Tackles Effects of NFL Hits’.

May’s Nature Reviews Neuroscience free on registration

The May edition of top brain research journal Nature Reviews Neuroscience is available online for anyone who completes the free site registration.

The issue contains a round-up of recent neuroscience news, as well as some in-depth reviews of depth perception, the genetics of nervous system development, olfactory memory in fruit flies, neural cycle cyle regulation and a fantastic article on the epigenetics of psychiatric disorder.

Epigenetics describes the process of how genes actually ‘do their work’.

DNA has two main functions. The ‘template function’ of DNA is to pass on genes through generations and allow different traits to be inherited.

The ‘transcriptional function’ of DNA is to allow these genes to be expressed at appropriate times and places (and not expressed at others) so the work can be done.

Almost every cell in the body has a copy of the DNA and, therefore, all the genes, but there are many types of cells with many diverse functions.

This is because not all genes are transcribed and expressed at once. Genes are expressed selectively.

This allows the body to have a diverse range of differently structured cells, and it allows the same cells to do different work at different times.

In a famous 1998 paper, Kandel noted that the transcriptional function of genes, that determines which proteins are expressed at any particular time, can be regulated by social, environmental and experiential (learning-based) factors.

This is why epigenetics is so important, because it is one way of understanding how genes and the environment interact.

We know that it is possible to inherit a variable risk for mental illness, and that life experiences are likely to combine with this risk to trigger mental illness in some people.

The Nature Reviews Neuroscience article looks at the latest research on how this occurs and how it might be different in various types of psychiatric disorder.

Link to May’s Nature Reviews Neuroscience (via Pimm).
Link to PubMed entry (with full text links) for Kandel’s classic 1998 paper.

Slate special on neuroscience

Slate has just released a special series on the brain – taking a critical look at some of the most recent developments in the field and asking researchers how neuroscience has changed their life.

There’s a wonderful article by developmental psychologist Alison Gopnick on getting past the hype surrounding mirror neurons – which are being used to explain almost every form of human behaviour despite the lack of evidence.

A host of brain researchers note how neuroscience has impacted on their day-to-day life and changes the way they see the world.

Most strikingly, Christof Koch notes that his research into consciousness convinced him to become vegetarian as “mammals can consciously experience the pains and pleasure of life”.

There’s also a few articles on cognitive enhancement: notably, one on the history and myths behind popular ‘brain supplement’ ginkgo biloba and another on neuroplasticity and the new craze for ‘brain training‘ programmes.

Neurotheology, the neuroscience of religious and spiritual experience, also gets a look in with an article examined the development of this new discipline and another on whether technology could induce spritual experiences via the brain.

I have to say, the article on the ‘five biggest neuroscience developments of the year’ is a bit ropey.

For example:

2. The neural alteration of morality. Six people with damage to the ventromedial prefrontal cortex were presented with moral dilemmas (e.g., would you smother a baby to prevent bad guys from finding and killing people in hiding) and were found to be two to three times more willing to kill than people without brain damage. The advertised conclusion is that such willingness to kill is objectively immoral. The feared conclusion is that if brain design determines what’s moral, you can change morality by changing the brain – and once technology manipulates ethics, ethics can no longer judge technology.

In fact, we’ve known for a very long time that brain damage can make people less moral, as the case of Phineas Gage suggested, and modern studies of ‘acquired sociopathy’ have reported.

It’s also interesting that the study in question found patients with ventromedial brain damage were actually more moral in utilitarian terms.

They were less swayed by the normal emotional response to making decisions that required trading off considerations of group welfare against emotionally negative behaviours (for example, having to sacrifice one person’s life to save a number of other lives).

Whether this is less moral, depends on your moral framework.

Generally, though, the series is well worth checking out and has some fascinating insights and commentary.

Link to Slate special series on the brain.

2007-04-27 Spike activity

Quick links from the past week in mind and brain news:

The BMJ had an fascinating editorial about the role of psychology in physical illness.

Deric Bownds discusses whether recursion a universal aspect of languages.

The Times Literary Supplement has a review of Hofstadter’s new book on consciousness.

Scientists debate the limits of action for autonomous robots.

Newsweek on new brain research that may help explain why some people don’t seem to learn from their mistakes.

Frontal Cortex discusses inequality and the perception of fairness.

Nature looks at a study that re-examined the two brains Paul Broca used to define the speech area now called Broca’s Area, with some surprising results.

Jeremy from PsyBlog reports the results of his study on music and personality we featured previously.

Study finds that although intelligence <a href="http://www.msnbc.msn.com/id/18311061
“>predicts income, it doesn’t predict wealth.

Scientific American ponders the scent of a man: pheromones from human males may be an important aspect of <a href="http://blog.sciam.com/index.php?title=eau_de_l_homme&more=1&c=1&tb=1&pb=1
“>attraction.

The BPS Research Digest looks at a study that asked the question ‘Can God make people more aggressive?’.

Cognitive Daily covers a study that used VR in a very creative way to understand the effect of eye gaze. The study created mutually exclusive social situations simultaneously experienced by all participants.

Psychology and neuroscience in book prize shortlist

A psychology and a neuroscience book have made two of out of the six entries shortlisted for the UK’s premier science book prize.

The award is the The Royal Society Prize for Science Books, previously called the Aventis Prize.

Daniel Gilbert’s entertaining book on the sometimes paradoxical world of the psychology of contentment, Stumbling on Happiness (ISBN 9780007183135), is one of the six.

In Search of Memory (ISBN 0393058638), Eric Kandel’s memoirs and discussion of the neuroscience of memory, also makes the list.

The full shortlist is at the link below.

Link to BBC News article on the 2007 shortlist.