Not seeing the wood for the trees

Simultanagnosia is where a person can’t perceive more than one object at a time. They literally cannot see the wood for the trees. There are two main types that differ depending on the location of the brain injury which has caused the syndrome.

Damage to the dorsal stream can cause dorsal simultanagnosia, where the patient cannot see two or more objects at the same time.

Damage to the ventral stream can cause ventral simultanagnosia, where the patient can see multiple objects, but can only identify one at a time.

The following is from p61 of the 1970 book Brain Damage and the Mind (ISBN 0140801405) by Moyra Williams, who describes a gentleman with dorsal simultanagnosia:

A sixty-eight-year old patient studied by the author had difficulty finding his way around because “he couldn’t see properly”. It was found that if two objects (e.g. pencils) were held up in front of him at the same time, he could see only one of them, whether they were held side by side, one above the other, or one behind the other.

Further testing showed that single stimuli representing objects or faces could be could be identified correctly and even recognized when shown again, whether simple or complex… If the stimuli included more than one object, only one would be identified at one time, though the other would sometimes “come into focus” as the first one went out…

If long sentences were presented, only the rightmost word could be read… If a single word covered as large a visual area as a sentence which could not be read, the single word was read in its entirety… If the patient was shown a page of drawings, the contents of which overlapped (i.e. objects were drawn on top of one another), he tended to pick out one and deny that he could see any others.

Recent evidence has suggested that although the unseen objects may not be consciously available, carefully designed psychological tests can detect they have been registered at some unconscious level.

The book Visual Agnosia by Prof Martha Farah covers a number of curious object perception disorders that occur after brain injury, including simultanagnosia.

The book’s webpage has a table of contents and some sample chapters freely available online.

Link to webpage for Visual Agnosia.

For Therapeutic Purposes

A poem from the book Uncut Confetti by the brilliant John Hegley:

For Therapeutic Purposes

I have not been quite right in the head
Like a balding tyre, I’ve been losing my grip
I have been given various medications
to help me cope
And my brother has given me
a skipping rope.

Hegley’s poems move effortlessly between the comic and the achingly poignant, and often touch upon the more curious aspects of human nature.

James Watson and the missing gene

The New York Times is reporting that James Watson, co-discover of DNA, will have the whole of his DNA sequence made publicly available, with the exception of one gene known as apolipoprotein E.

Watson doesn’t want to know which version of the gene he has, as it is one of the strongest predictors for the development of Alzheimer’s disease.

In fact, it’s the only gene which has specifically been shown to increase risk for the brain disorder.

The gene for apolipoprotein E, or ApoE as it is more widely known, comes in three main forms or alleles called ApoE ε2, ε3 and ε4.

Studies have consistently shown that the more ApoE Œµ4 alleles you have, the higher the chances of developing Alzheimer’s disease and the younger the age it will begin to take effect.

In fact, having two ApoE Œµ4 alleles virtually guarantees you’ll have Alzheimer’s by the age of 80 and if you do get Alzheimer’s disease, the presence of this allele seems to make it more likely that you’ll experience delusions and psychosis.

The gene codes for the apolipoprotein which combines with fats (such as cholesterol) in the body and transports them to various places, including the liver, where they are broken down.

Alzheimer’s disease is linked to the accumulation of ‘amyloid plaques’ and ‘neurofibrillary tangles’ in the brain, both of which are abnormal clumps of protein.

The presence of the ApoE ε4 allele makes these protein clumps more likely, even in people who have not developed the disorder.

However, the exact link between ApoE and fat processing, protein clumps and Alzheimer’s disease is still not fully understood.

What Watson does understand, however, is that he could work out how likely he is to develop Alzheimer’s disease from the versions of the gene he carries, and it seems he’d rather not live with the knowledge.

This is not an uncommon situation, as people with genetic disorders, or people whose close family have genetic disorders, often have to decide whether they want to know the chances of them or their children developing a potentially life-threatening disease.

Genetic counselling is a service that assists the the person in understanding the risks and possible outcomes based on the science of genetics, as well as dealing with the emotional impact of the sometimes difficult process of discovery and decision-making.

Link to NYT article ‘Genome of DNA Discoverer Is Deciphered’.

Neurotech industry consultant profiled

The San Francisco Chronicle has an article on neurotech industry consultant Zack Lynch, who you might know from the blog Brain Waves.

Lynch is executive director of the Neurotechnology Industry Organization, an umbrella organisation for the commercial neuroscience sector, and managing director of NeuroInsights, a business intelligence service.

The San Francisco Chronicle article looks at Lynch’s aims and work, in partnership with his wife, neurobiologist Casey Lynch, as well as giving an insight into how the neurotech industry is becoming an increasingly important force in the marketplace and in policy making.

Lynch is an interesting guy to watch. He’ll always pitch for industry, but his job relies on him having a balanced view of what’s likely to work out in the marketplace.

Interestingly, the article also notes he’s written a book on the neurotech industry that’s recently found a publisher:

The first neurotechnology project Lynch took on in 2001, a book titled “Brain Waves,” just landed a publisher. The book allows Lynch to take his favored “200-year view,” speculating on how business, politics and culture will evolve in a future era of neurotech inventions that might change the way people think and communicate. Lynch is fascinated by the ethical and social dilemmas that might emerge. If drugs can enhance memory, for example, would college entrance exams still be fair? “Who’s going to be able to afford this?” Lynch asks.

Link to article ‘Brainstorming about the brain’.

SciAmMind on team success and kids on drugs

The latest edition of Scientific American Mind has just been published, and as is customary, two of the feature articles are freely available online.

The first is on the psychology of teams and how science is attempting to understand what makes a successful and productive working party.

The article describes effective team learning strategies and how emotions help groups bond during work.

These researchers trained college students to assemble transistor radios either alone or in groups of three. A week later the subjects were tested with their original group or, for people who received solo training, in newly formed groups. Members of groups that had trained together remembered more details, built better-quality radios and showed greater trust in fellow members’ expertise. People in newly formed groups were less likely to have the right mix of skills to complete the task efficiently and knew less about one another’s strengths.

The second article looks at the controversial topic of prescribing psychiatric drugs to children and evidence that the use of psychiatric drugs alters the growing brain.

This is weighed up against the evidence that in children with serious mental illness, an untreated disorder may alter the growing brain.

It’s a difficult topic because it often boils down to picking the lesser of two evils, although, because of lack of research, it’s often not easy to tell which will have the least negative effect for any given child.

It’s a fascinating article on one of the major issues facing psychiatry today.

There are also articles on expertise and the role of mirror neurons in stroke recovery in the full edition, as well as all the regular features.

Link to article ‘The Science of Team Success’.
Link to article ‘Kids on Meds — Trouble Ahead’.

Identity disorder and the future of technology

Polymath physician Dr Ray Tallis has written an optimistic article in the latest edition of Philosophy Now magazine arguing that human technological enhancement is over-hyped but no reason for fear.

Tallis is a professor of geriatric medicine, so it’s no surprise that he sees some of the most applicable benefits of technological advances for diseases like Alzheimer’s and Parkinson’s.

Critics have suggested that using technology to enhance human abilities, whether by drugs, implants or genetics, will lead to an erosion of our sense of identity.

Tallis looks back on past promises and argues that this is unlikely to be the case:

The most often repeated claim is that we are on the verge of technological breakthroughs – in genetic engineering, in pharmacotherapy and in the replacement of biological tissues (either by cultured tissues or by electronic prostheses) – which will dramatically transform our sense of what we are and will thereby threaten our humanity. A little bit of history may be all that is necessary to pour cooling water on fevered imaginations.

In 1960, leading computer scientists, headed by the mighty Marvin Minsky, predicted that by 1990 we would have developed computers so smart that they would not even treat us with the respect due to household pets. Our status would be consequently diminished. Anyone seen any of those? Smart drugs that would transform our consciousness have been expected for 50 years, but nothing yet has matched the impact of alcohol, peyote, cocaine, opiates, or amphetamines, which have been round a rather long time.

As well as making some telling philosophical points, the article is quite funny in places, as Tallis uses some of his literary skills to good effect.

Link to Philosophy Now article ‘Enhancing Humanity’.

Freud, neurobiology and psychotherapy

American TV discussion host Charlie Rose has a series of programmes available online where some of the world’s leading researchers discuss Freud, neurobiology and the latest in psychological treatments for mental illness.

The first programme is a discussion of the legacy of Freud, with neurobiologist Eric Kandel, Freudian psychotherapist Peter Fonagy, inventor of cognitive therapy Aaron Beck and psychiatrist Charlie Roose.

It is a great guide to the differences between Freudian and cognitive approaches to psychotherapy, as well as how it relates to brain function and modern neuroscience.

A second programme looks at a similar topic, but expands the discussion to include cognitive psychological research and also includes psychologists Nancy Kanwisher, Nora Volkow, Rebecca Saxe and Liz Phelps.

Finally, one is a special interview with Eric Kandel, which is guest hosted by fellow Novel Prize winner Harold Varmus, who, incidentally co-founded PLoS – the organisation behind some of the world’s finest open-access science journals.

2007-06-01 Spike activity

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

A disquieting feeling of strangeness?: Just found this great 2001 paper on the ‘the art of the mentally ill’ on PubMedCentral.

Brain scan can predict response to antidepressants, reports New Scientist.

Neurophilosophy has an excellent article on famous amnesia case HM.

Pesticides ‘up Parkinson’s risk‘ according to BBC News.

Scientific American reports that Scottish scientists uncover a striking link between genes for brain size and tonality in spoken language.

Developing Intelligence investigates the neuroscience of imagination.

Forbes profile a cognitive scientist. Still no word from Hello magazine.

The rate of diagnosed clinical depression among retired American football players is strongly correlated with the number of concussions they sustained, reports The New York Times.

Pure Pedantry looks at research on storing computer information in biological neurons.

Young children can crudely add and subtract numbers before they have learned the rules of arithmetic, reports Scientific American.

Brain Ethics highlight a new book by the widely liked and respected neuroscientist, Chris Frith.