Two smell systems in the human brain

Today’s Nature has a special supplement on chemical sensing, including a freely accessible article on smell and the flavour system that is full of surprising facts about one of the most neglected senses.

For me, one of the most surprising aspects of the article, was discovery that there are two distinct brain networks for smell.

One is the orthonasal system which deals with odours ‘sniffed in’ to the nose, and the other is the retronasal smell system (image on the right, click for larger version of both) which is involved in sensing odours when we breath out.

The retronasal system is particularly linked to the flavour system, because it is most commonly activated when we eat food.

The traditional view in the literature on eating behaviour in human culture is that the flavour of prepared foods is humanity’s greatest universal shared behaviour, experienced by individuals of all ages in the course of daily life. Flavour is also among the most complex and powerful of all human sensations. It engages almost all of the sensory modalities. It also engages the complex facial, swallowing and respiratory motor systems. Flavour is therefore an active sensation ‚Äî we use ‘active taste’ to palpate our food with our tongue as we use ‘active touch’ to palpate an object we are examining with our fingers. Some of these systems are indicated in the diagram [above]. Above these sensory and motor systems are the cognitive systems for memory, emotion, abstract thinking and language. The importance of retronasal smell images is illustrated by the massive extent to which they interact with these brain systems compared with orthonasal smell images

The article also discusses the how smells are transformed into spatial odour patterns in the brain depending on which sensors the odour activates, and notes that smell-related genes are the largest group in the genome.

All in all, it’s a really eye-opening article if, like me, you’re not familiar with the surprising and complex nature of our sense of smell.

Link to article ‘Smell images and the flavour system in the human brain’.

A neuroscientist’s life’s work

The International Herald Tribune has a fascinating article on the work of neuroscientist Prof Sandra Witelson.

Witelson is notable for collating the world’s largest ‘brain bank’ of non-diseased human brains.

She is particularly interested in examining how brain structure relates to mental function, and particularly in sex differences between men and women.

Her research has turned up some intriguing differences between the structures of male and female brains, usually not obviously visible on brain scans, as they are at the cellular level and only in specific areas.

Witelson also got the chance to study a particularly exceptional brain:

It was Witelson’s 1999 study of Albert Einstein’s brain that made headlines by revealing some remarkable features overlooked by other neuroscientists: the parietal lobe, the region responsible for visual thinking and spatial reasoning, was 15 percent larger than average, and it was structured as one distinct compartment, instead of the usual two compartments separated by the Sylvian fissure.

Witelson is continuing her analysis of Einstein’s brain, but with a histological study, probing features of the cellular geography in the parietal lobe, like the packing density of his neurons.

These specimens of Einstein’s brain came to Witelson via Dr. Thomas Harvey, the pathologist at the Princeton hospital where Einstein died in 1955. Shortly thereafter Harvey stole away with the great man’s gray matter (and lost his job as a result).

Now 94, Harvey has received requests for Einstein’s brain from many neuroscientists and turned most of them down. But hearing of Witelson’s extensive brain bank, he sent her a handwritten note by fax in 1995 asking simply, “Do you want to study the brain of Albert Einstein?”

She sent a fax back: “Yes.”

Link to ‘A neuroscientist’s life’s work: Analyzing brains to study structure and cognition’.

NewSci’s half century of big questions

New Scientist turns 50 today, and to celebrate, they’ve reprinted some classic news stories from their archives and have predictions from a clutch of contemporary scientists.

The only neuroscience-related story from the archive is the discovery of endorphins, natural pain-killing opioids in the brain, from way back in ’76.

Cognitive scientists make more of a showing in the section on predictions about the future with Rodney Brooks, Steven Pinker, Elizabeth Loftus, Igor Aleksander, Geoffry Miller, Terry Sejnowski, Eric Horvitz, Frans de Waal and Michael Gazzaniga all making their pitches.

Some of the feature articles, only available to paying subscribers, also tackle mind and brain issues, as the magazine attempts to describe some of the biggest problems still facing science.

Articles on ‘What is consciousness?’, ‘What is reality?’, ‘What comes after Homo sapiens?’ and ‘Do we have free will?’ all cover areas of interest to psychology and neuroscience enthusiasts.

Link to NewSci 50th anniversary edition details.

The maze of child psychiatry

The New York Times has published the first two parts of an ongoing series on the experience and difficulties of diagnosing mental illness in children.

The area of child mental illness is controversial, largely because diagnosis is so difficult.

Diagnosing adults is tricky at the best of times, but mental disorder seems to appear differently in children and is often classified using specific diagnoses.

Some disorders, such as conduct disorder or childhood autism, can only be diagnosed in children, while others, such as psychotic disorders, could technically be diagnosed but are incredibly rare in pre-adolescents.

Some diagnoses are subject to significant cultural differences. For example, some American psychiatrists are diagnosing children with bipolar disorder as young as 6-years-old, while most British psychiatrists tend to be quite unhappy with this, and in practice, rarely diagnose anyone under 18 with the condition.

At the moment, awareness of ‘Juvenile Bipolar Disoder’, as it has been christened, is being heavily promoted in America.

For example, the Juvenile Bipolar Research Foundation website even lets you ‘screen’ your own child with an online questionnaire to see if they have the condition.

Cynics may note that the organisation is sponsored by, among others, Novartis Pharmaceuticals and make accusations of disease mongering, while supporters would argue that it is increasing awareness of an under-recognised disorder and hope that it will lead to better treatment for children in distress

One of the concerns of these diagnoses, is that they typically lead to substantial drug treatment, the long-term effects of which are not well understood or researched.

The first NYT article explores the experience of one family who had a daughter who developed behavioural problems and started experiencing psychotic symptoms at the age of 7, a very uncommon occurrence.

The second article looks at the process of diagnosis itself, and what difficulties psychiatrists face when trying to separate bizarre but normal childhood fantasy from troubling thoughts and feelings.

This is an especially difficult task in children who do not necessarily have the language or mental abilities to fully communicate their own experiences.

Both articles have video and a photo essay to accompany them. Presumably, more articles in the series will be forthcoming.

Link to NYT article ‘Living With Love, Chaos and Haley’.
Link to NYT article ‘What‚Äôs Wrong With a Child? Psychiatrists Often Disagree’.

Lights, camera, madness – Bollywood style

Bollywood, the world’s largest film industry, seems to be showing a new, more positive interest in mental illness.

As The Mouse Trap reports, one of the most popular films of the year, Lage Raho Munna Bhai (‘Carry on Munna Bhai’) depicts a local gangster, Munna, who becomes obsessed with the ideas of Mahatma Ghandi.

Munna subsequently hallucinates the presence of Ghandi and experiences the delusion that he is being guided by the long-dead leader.

The film has won praise from Indian psychiatrists for its positive portrayal of the sorts of unusual experiences that are typical of psychotic conditions.

According to Reuters, the sensitive portrayal of mental illness is set to continue with a forthcoming Bollywood film, provisionally entitled “Bits and Pieces”, which will actually be set inside an asylum.

“Bits and Pieces,” starring Bollywood actor Rahul Bose, known for portraying unconventional roles, promises to be one such film that balances the sensibilities of the art-house genre with popular appeal.

“It is a movie about a writer in India who decides to visit a lunatic asylum for his next novel,” Bose told Reuters. “It shows how he gets emotionally attached to the people living in the asylum, his emotional tumult thereafter and his wish to do something for them.”

Watching inmates of the asylum and their myriad interactions from close quarters make Bose question popular notions of sanity and madness to a point where he seems to find a reason in defense of insanity.

“After seeing the so-called insanes, the writer fails to distinguish whether those who have been put inside the asylum are mad or those who have put them inside are,” Bose, 39, said about the protagonist’s dilemma.

Indian cinema has an long and fascinating history of reflecting cultural attitudes to mental illness.

Psychiatrist Prof Dinesh Bhugra published a landmark paper and book on the representation of madness in Bollywood, and has noted that it often mirrors social and political changes in India itself.

Bhugra argues that in the 1950s and the mid-1960s, the years of ‘hope and achievement’ for India, mental illness was portrayed in a gentle and even romantic way.

As social and political turmoil followed through the 1970s, 80s and 90s, madness became to be portrayed as dangerous and obsessive.

Hopefully, the new optimism in modern India is being reflected in films with positive messages about mental health.

Link to The Mouse Trap on madness in film.
Link to abstract of paper on madness in Bollywood.
Link to details of book ‘Mad Tales from Bollywood’.

Haynes Brain Manual

Haynes, the maker of the well-known manuals on car mechanics, have released a Haynes Brain Manual (ISBN 1844253716) that gives tips and advice on keeping your mind and brain running smoothly.

Covering everything from exercise and nutrition for optimal brain function, to dealing with stress, to getting help with mental or neurological health problems, the manual seems to be fun and informative guide to possible solutions and resources available.

It not only gives personal advice but also includes a guide to dealing with professional services and tracking down the right sort of help when you need it.

It’s mainly targeted at men, and probably fills a gap in the market which is often missed by most blokes’ magazines.

The website has a selection of pages from the book available as PDF files if you want to have a look inside.

Link to Haynes Brain Manual page.

Neuroanatomy illustrated, 1832

America’s National Library of Medicine have put scans of beautiful old medical texts online including Jospeh Vimont’s wonderfully illustrated 1832 anatomy book entitled Trait√© de phr√©nologie humaine et compar√©e that compares the skull and brain of humans and animals.

Despite the French title, it’s annotated in both English and French and contains some fantastic illustrations of both normal and abnormal neuroanatomy.

Apparently, it was an attempt to investigate the links between brain structure and the ‘science’ of phrenology which claimed that bumps on the head indicated personality because they suggested how the brain was developing underneath.

Although phrenology has been discounted as rubbish, it is credited with sparking some of the first ideas on whether specific brain areas could be involved in specific mental abilities, an idea that is now central to modern cognitive neuroscience.

People who take this idea too far, by suggesting that there is a ‘brain centre’ for some particular complex behaviour are often accused of being ‘modern day phrenologists’ (usually with an accompanying look of disdain or a loud tut).

Unfortunately, the media loves stories that go something like “‘Dream centre’ of the brain found” (a real headline) which encourages reporters to distort the usually ambiguous findings of research studies, and scientists to over-simplify their conclusions.

In contrast, Vimont’s book is a form of innocent and sincere phrenology and, perhaps, should be enjoyed as such.

Link to Traité de phrénologie humaine et comparée (via BB).

Inside a 7-tesla brain scanner

There’s a news story and video clip on the BBC News website about a reporter’s experience of being inside the new 7-tesla fMRI scanner at Nottingham University.

Tesla is a measure of magnetic field strength and the greater the field strength of an fMRI scanner, the more detailed images it is likely to produce.

Most scanners are 1.5-tesla, or more recently, 3-tesla, with only a few 7-tesla machines in existence.

You’ll occasionally hear scientists who work with fMRI-scanners proudly announce the field strength as if it were a measure of, well… I’m sure you can guess.

The report is interesting both for the 1970s footage of Nobel Prize winning MRI inventor Peter Mansfield inside the first ever MRI machine, and for the completely bizarre ‘MRI picture frame’ example used half way through the clip.

Link to BBC News story and video clip link.
Link to info page on Nottingham Uni’s 7-tesla scanner.

The masked, gay, anonymous psychiatrist

I just read a news item in Psychiatric News on the first John E. Fryer M.D. Award, named after the man who appeared in disguise as Dr H. Anonymous at the 1972 American Psychiatric Association conference to declare he was a gay psychiatrist at a time when homosexuality was still classified as a mental illness.

This has been cited as a key factor in getting homosexuality de-listed from the diagnostic manual the following year, and was a landmark event both in the history of psychiatry and gay rights.

Consequently, I was surprised to find that there was nothing about John Fryer on Wikipedia, despite having been honoured by having an award named after him and obituaries in the leading medical journals when he passed away in 2003.

So, I’ve put together a Wikipedia page for John E. Fryer with some of the fascinating story and details, but this is where I need your help.

Although I know a little about the history of psychiatry, I’m afraid I don’t know a great deal about gay culture or history, so if you do, please expand the article and mesh it in with the other relevant articles on Wikipedia.

Also, if anyone knows of any open-licensed pictures of Dr Fryer or Dr Anonymous to include in the article, or can get permission to use any pictures, please do so.

Finally, there are more details in the information in the ‘external links’ section, so if you have a few minutes to rewrite it in your own words to add to the article, this would also be very useful (and any factual corrections or fixes to my dodgy prose are also welcome!).

Link to Wikipedia page for Dr John E. Fryer.
Link to text of Dr H. Anonymous’ 1972 speech.

Mirror neurons as an explanation for autism

This month’s Scientific American has a cover story on why differences in the ‘mirror neuron‘ system may explain the social difficulties in autism – and an extended preview is available online.

Mirror neurons are cells in the brain that are active both when a person is performing an action, or when they see someone else perform an action, and have been hypothesised to be involved in perceiving and comprehending others’ actions.

The preview is written by neuroscientists V.S. Ramachandran and Lindsay Oberman and introduces an extended article (not freely available online) that argues that people with autism may develop with a dysfunctional mirror neuron system, making them less able to make sense of social interactions.

This basic difficulty could then lead to the common autistic features such as abnormalities of language development, non-verbal communication, emotion recognition and understanding others’ intentions, which all rely on social interaction to develop fully.

‘Mirror neurons’ were first discovered in monkeys by Giacomo Rizzolatti, author of the extended article. However, the mirror neuron system is poorly understood in humans, despite some interesting findings in the research literature.

Ramachandran is currently one of the most enthusiastic ‘mirror neuron’ evangelists, going as far as saying “I predict that mirror neurons will do for psychology what DNA did for biology”.

One of the difficulties with this research, is that when compared on a task that involves understanding others’ actions in some way, people with autism tend to perform worse than a non-autistic comparison group.

This makes it difficult to say whether differences in performing the task are really due to differences in the mirror system, or whether it’s a more general problem, such as learning or perception difficulties.

Nevertheless, one recent study has provided some of the best evidence that mirror system differences may genuinely be present.

A team led by neuroscientist Dr Mirella Dapretto asked children with autism who had normal IQ scores to observe and imitate emotional expressions while in an fMRI brain-scanner.

They were compared to non-autistic children and the researchers found that both groups of children performed the task equally well.

Crucially, the children with autism did not show brain activity in an area of the frontal lobe called the pars opercularis – part of the ‘mirror neuron’ system.

This provides strong evidence of differences in the mirror neuron system in autism, although why this difference occurs is still a matter of debate.

For those wanting a good scientific review of the research in this area, a pdf of a recent paper by Vittorio Gallese, one of the co-authors of the extended Scientific American article, is available online.

Link to SciAm preview article ‘Broken Mirrors: A Theory of Autism’.
Link to abstract of Dapretto study.
Link to coverage of Dapretto study from BBC News.
pdf of Vittorio Gallese’s review on mirror neurons and autism.

2006-11-10 Spike activity

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

Cognitive Daily has a fantastic post on how the brain synchronises sound and vision, even when they’re out of sync (including videos!).

Psychology Today argues that mass-media ‘beauty’ is making people unhappy in Why I hate beauty.

Web pioneers call for a new discipline of ‘web science‘ that combines psychology, economics and law, computer science and engineering.

Developing Intelligence discusses two ways of understanding children who are ‘late talkers’: the nativist and interactionist approaches.

Having a high IQ protects against developing PTSD after major trauma, finds new study.

Computer modelling of shock waves inside the head suggests that brain injury may occur within one millisecond after the head hits a car windshield.

Neurofuture posts on an freely accessible online sci-fi novel on consciousness uploading, AI and zombies (oh my!)

New Scientist reports that industrial chemicals that seep into the environment may increase risk of developmental brain disorders.

Researchers have developed a 3D map of the human body to allow people to better communicate pain.

Children prefer to be friends with children perceived to be lucky, finds new study.

The Neurophilosopher has written an engaging and wonderfully illustrated article on the history of Alois Alzheimer and the disease that bears his name.

Who wants to be a neurillionaire?

Seed Magazine has a fantastic article written by Ogi Ogas, a doctoral student in cognitive neuroscience who applied techniques from cognitive psychology to win a cool half-million on the show ‘Who wants to be a Millionaire?’

Taking advantage of psychological processes such as priming and the structure of associations in memory, Ogas devised strategies to optimise his chances of winning.

The first technique I drew upon was priming. The priming of a memory occurs because of the peculiar “connectionist” neural dynamics of our cortex, where memories are distributed across many regions and neurons. If we can recall any fragment of a pattern, our brains tend to automatically fill in the rest….

I used priming on my $16,000 question: “This past spring, which country first published inflammatory cartoons of the prophet Mohammed?” I did not know the answer. But I did know I had a long conversation with my friend Gena about the cartoons. So I chatted with Meredith about Gena. I tried to remember where we discussed the cartoons and the way Gena flutters his hands. As I pictured how he rolls his eyes to express disdain, Gena’s remark popped into my mind: “What else would you expect from Denmark?”

The article is a fascinating insight into both the psychology of quiz shows, and how lab-based cognitive science relates to more pragmatic real-life situations.

Link to Seed Magazine article (thanks Paul and Candace!).

Is that a hydraulic shovel in your pocket…?

There’s nothing more interesting than people. The diversity of the human race is the main reason why I find psychology and neuroscience so fascinating.

The following summary of an article from the Journal of Forensic Science is an amazing demonstration of how diverse the human race can be, sadly with tragic consequences in these cases.

Autoerotic fatalities with power hydraulics

Journal of Forensic Science, 1993, Vol 38, Issue 2, p359-64.

We report two cases in which men used the hydraulic shovels on tractors to suspend themselves for masochistic sexual stimulation. One man developed a romantic attachment to a tractor, even giving it a name and writing poetry in its honor. He died accidentally while intentionally asphyxiating himself through suspension by the neck, leaving clues that he enjoyed perceptual distortions during asphyxiation. The other man engaged in sexual bondage and transvestic fetishism, but did not purposely asphyxiate himself. He died when accidentally pinned to the ground under a shovel after intentionally suspending himself by the ankles. We compare these cases with other autoerotic fatalities involving perceptual distortion, cross-dressing, machinery, and postural asphyxiation by chest compression.

The last sentence is typically academic and wonderfully deadpan.

Link to PubMed entry for the article.