Alzheimer’s risk gene may boost memory in young

A fascinating study published in this month’s Cerebral Cortex reports that a gene known to massively increase the risk of Alzheimer’s disease in later life is associated, in young people, with better memory performance and more efficient use of the brain’s memory structures.

The research team, led by neuroscientist Christian Mondadori, looked at the genetics and memory performance of 340 volunteers, all in their early 20s.

The team were particularly interested in which version or allele of the apolipoprotein E (ApoE) gene each person had, because the ‘Epsilon 4’ allele raises the risk for Alzheimer’s disease in old age.

In fact, people with two ‘Epsilon 4’ alleles are virtually guaranteed to the brain disorder by the age of 80.

Each person took part in a word learning test that involved both short-term and long-term memory. This type of test is known to particularly rely on the function of the hippocampus, a key memory area which is known to decline in Alzheimer’s disease.

People who were carriers of the Epsilon 4 allele performed better in the long-term memory test, and no different for short-term memory.

The team decided to do more extensive memory tests while brain scanning 34 participants who were picked specifically to represent equal numbers of the three common genetic combinations.

These tests in the scanner involved learning faces and associations with professions over a number of trials and a target detection task that involved manipulating information in short-term memory (working memory).

There was no difference between the groups in terms of their accuracy on these tests, but people with the Epsilon 4 allele showed decreases in brain activity as time went on, suggesting they were using their brain more efficiently.

In contrast, people without the Epsilon 4 allele showed increases in brain activity, suggesting their brain was having to work harder to keep up.

A key question is why people who carry the Epsilon 4 allele would have a more efficient brain system for memory in early life but are more likely to have these same memory systems degrade in later life, as happens in Alzheimer’s disease.

As Alzheimer’s typically strikes after the time most people have children, the researchers suggest that the Epsilon 4 allele could confer an evolutionary advantage without adversely affecting chances of reproduction.

Some evidence that supports this idea has been found in previous studies where the ApoE Epsilon 4 allele has been associated with higher IQ scores, reduced heart activity under stress, and reduced chance of difficulties during pregnancy and post-birth problems.

Link to abstract of scientific study.

Old School Neurophysiology

squidaxon.jpgThe Plymouth Marine Laboratory brings us footage of experiments on the giant axons of the squid — the work that brought us the action potential. Quoting:

“The Squid and its Giant Nerve Fiber” was filmed in the 1970s at Plymouth Marine Laboratory in England. This is the laboratory where Hodgkin and Huxley conducted experiments on the squid giant axon in the 1940s. Their experiments unraveled the mechanism of the action potential, and led to a Nobel Prize. Long out of print, the film is an historically important record of the voltage-clamp technique as developed by Hodgkin and Huxley, as well as an interesting glimpse at how the experiments were done. QuickTime video excerpts from the film are presented here.

Link: excerpts from The Squid and its Giant Nerve Fiber

(via Three-Toed Sloth)

Metal casing, mental illness and masturbation

The image is taken from the psychiatry section of the Science and Society picture library and depicts a male anti-masturbation device from the late 19th / early 20th century, and, believe it or not, was considered an effective way of preventing insanity.

Masturbation was long linked to madness in both folk and professional medicine and this belief lasted, even among professionals, until the early 1900s.

It was thought a particular mental health risk in children, as illustrated by this excerpt from a 1988 article on the development of child psychiatry in 19th century Britain.

William Acton, trained in surgery and venereal diseases, published The functions and disorders of the reproductive organs, in youth, in adult age and in advanced life in 1857. It gained immediate popularity and went through six editions in 18 years, despite it’s many discrepancies, premature conclusions and emotional prejudices (Marcus, 1966).

Typical of most authors of the time, Acton on the one hand postulates that normal childhood is essentially asexual, on the other describes over many pages the many sexual disorders of childhood — a conflict that is never resolved. Again, without further explanation, a causal connection between masturbation and a whole array of consequences is drawn: the boy would become haggard, thin, antisocial, hypochondriacal, would lose his spontaneity and cheerfulness and would turn into a timid coward and liar. The final state was one of idiocy, epilepsy, paralysis and even death.

These prejudices were considered valid scientific facts, so that the Scottish psychiatrist David Skae even created the term “masturbatory insanity” ‚Äî a separate nosological disease caused exclusively by masturbation, with characteristic features (Skae, 1874). This term was taken up by Henry Maudsley (1868); the 1879 edition of Pathology of mind included a chapter devoted to the insanity of masturbation (Maudsley, 1879), which was later changed to insanity and masturbation (Maudsley, 1895).

I’ll save you the gory details, but these beliefs led to supposed ‘treatments’ and ‘preventative measures’ that stretched from devices like the one pictured, to what would now be considered brutal genital mutilation of both boys and girls.

If you think that these were fringe beliefs, it’s worth remembering that Henry Maudsley was otherwise considered the greatest psychiatrist of his generation.

Link to picture from Science and Society image library.

Chasing Memory with romantic science

Frontal Cortex has just alerted me to a compelling four-part series on the quest to find the molecular basis of memory in Prof Gary Lynch’s neuroscience lab.

It’s not only an account of the science behind the research, but also of the characters and human drives of the people involved.

Old school Russian neuropsychologist A.R. Luria wrote case studies of brain injured patients that not only described the neuroscience of their disorders, but also described the people in such sensitive detail that you really felt you got to know them.

He called this ‘romantic science’ – something which Oliver Sacks cites as a major inspiration for his own work.

These LA Times pieces are not about brain injury, but they have the same quality of human passion intertwined with the story of scientific discovery.

The first time I spoke with the neuroscientist Gary Lynch, the conversation went something like this:

Me: I’m interested in spending time in a laboratory like yours, where the principal focus is the study of memory. I’d like to explain how memory functions and fails, and why, and use the work in the lab as a means to illustrate how we know what we know.

Lynch: You’d be welcome to come here. This would actually be a propitious time to be in the lab.

Me: Why’s that?

Lynch: Because we’re about to nail this mother to the door.

Link to four-part LA Times special ‘Chasing Memory’.

Psychological continuity and the problem of identity

Philosophy Now magazine has an interesting article on the problem of identity – how we have the impression that we are the same person, despite the fact that our personality, preferences and even cognitive abilities may change from moment to moment.

It’s a problem that was most famously tackled by 17th century philosopher John Locke but is still relevant for understanding the issues of identity and the self in contemporary cognitive science, as well as for informing complex judgements on free will and responsibility.

Suppose a man has committed a crime whilst drunk or undergoing temporary amnesia. Suppose also, that because of his mental state at the time of the offence, he genuinely cannot remotely remember a thing about it. Clearly on the evidence of witnesses ‚Äì and perhaps he was caught in the act ‚Äì it was his own body, the same man who now stands in the dock, who did it. But was it the same person? Should the present person be found guilty of the crime if the drunkenness or amnesia had so changed his psyche that, at the time, he ‘wasn’t his true self’? Can he rightly claim that at the time of the incident the occupant of his body was a different person altogether; or perhaps some fractured component of his own psyche that couldn‚Äôt rightly be described as ‚Äòhimself‚Äô?

Psychological continuity was, Locke claimed, the answer to the question. The accused, considered as a man, the physical being, is certainly guilty. His own hand struck the blow, his own voice had risen in anger. But if the person, the psychological being, cannot remember one atom of it, then he is not guilty.

But though Locke’s theory answered the question, it‚Äôs not certain that it solved the problem; for it raises a paradox that will try the wits of the jurists: the man in the dock may be guilty, but not the person in the man! And if the man is punished, he will experience the pain, but the wrong person will suffer it.

Link to article ‘A Question of Identity’ (via Thinking Meat).

US psychologists snub CIA but scrap total ban

After much debate at the American Psychological Association conference a resolution was passed that condemns torture, bans psychologists from taking part in certain abusive activities, but still leaves significant grey areas for participation in contested CIA interrogation techniques.

The key section of the APA resolution is the following:

This unequivocal condemnation includes, but is by no means limited to, an absolute prohibition for psychologists against direct or indirect participation in interrogations or in any other detainee-related operations in mock executions, water-boarding or any other form of simulated drowning or suffocation, sexual humiliation, rape, cultural or religious humiliation, exploitation of phobias or psychopathology, induced hypothermia, the use of psychotropic drugs or mind-altering substances used for the purpose of eliciting information; as well as the following used for the purposes of eliciting information in an interrogation process: hooding, forced nakedness, stress positions, the use of dogs to threaten or intimidate, physical assault including slapping or shaking, exposure to extreme heat or cold, threats of harm or death; and isolation, sensory deprivation and over-stimulation and/or sleep deprivation used in a manner that represents significant pain or suffering or in a manner that a reasonable person would judge to cause lasting harm; or the threatened use of any of the above techniques to the individual or to members of the individual’s family;

The resolution is widely being interpreted as a snub to the CIA, but notably, participation in detainee “isolation, sensory deprivation and over-stimulation and/or sleep deprivation” are not specifically banned unless they are judged to cause “lasting harm” – without any clear definition of what this amounts to.

Salon points to a publicly available CIA interrogation manual from the 1960s that notes that these techniques quickly provoke hallucinations and stress that become “unbearable for most subjects” although the manual also notes a “profound moral objection to applying duress past the point of irreversible psychological damage.”

Some members were pressing for an outright ban in participation in all CIA interrogations, citing the whole process of internment without due process unethical, but this was not adopted by the APA, meaning the guidelines fall short of those already adopted by psychiatrists and physicians.

One notable aspect of this story is just how important it’s become. At the time of writing, Google News lists over 300 news items on the decision.

Much of the credit for this has to go to Salon who have followed the story since the beginning, at times catching APA with their pants down.

Their dogged investigations have obviously touched a nerve as they report that the APA president refused to answer questions from the publication when approached after a panel session.

Link to APA resolution.
Link to Salon article ‘Will psychologists still abet torture?’.
Link to APA press release on resolution.

The cognitive science of magic

The Association for the Scientific Study of Consciousness invited some of the world’s best stage magicians along to their June conference to demonstrate how the conscious mind can be manipulated. The New York Times has just published a fantastic article on the conference and the cognitive science of magic.

The symposium was entitled ‘The Magic of Consciousness’ and was deliberately more than just light entertainment. The magicians were specifically chosen for the interest in the cognitive aspects on illusion and talked on how they take advantage our of brain’s quirks.

“This wasn’t just a group of world-class performers,” said Susana Martinez-Conde, a scientist at the Barrow Neurological Institute in Phoenix who studies optical illusions and what they say about the brain. “They were hand-picked because of their specific interest in the cognitive principles underlying the magic.”

She and Stephen Macknik, another Barrow researcher, organized the symposium, appropriately called the Magic of Consciousness.

Apollo, with the pull of his eyes and the arc of his hand, swung around my attention like a gooseneck lamp, so that it always pointed in the wrong direction. When he appeared to be reaching for my left pocket he was swiping something from the right. At the end of the act the audience applauded as he handed me my pen, some crumpled receipts and dollar bills, and my digital audio recorder, which had been running all the while. I hadn’t noticed that my watch was gone until he unstrapped it from his own wrist.

Link to NYT article ‘Sleights of Mind’.
Link to list of symposium speakers and talks.