Monday, April 28, 2003

"Hearing Colors, Tasting Shapes" by Vilayanur S. Ramachandran & Edward M. Hubbard. 4/25/2003

For people with synesthesia, the five senses (touch, hearing, taste, vision, and smell) get mixed up instead of remaining separate. These otherwise normal people might see printed black numbers in color, or smell flowers when listening to music. The first scientific description was published by Francis Galton, in an 1880 issue of the journal Nature. But the phenomenon has often been dismissed as a trick of memory, a symptom of hallucinogen use, or outright fakery.

The authors of the current review designed puzzle-like experiments that subjects could only solve if they, in fact, perceived the world as they claimed. For example, in a field of black number 5's, black number 2's were arranged in a triangle shape. Normal people had trouble picking out the triangle. To synesthetes, the 2's actually appeared to be a different color from the 5's, and so the triangle was easily distinguished from its background.

The cause appears to be some form of "cross-wiring" or chemical transmitter "cross-activation" of higher order sensory processing in the brain. The authors cite previous research as showing synesthesia to be seven times more common in "creative" people than in the general population, and suggest a link between synesthesic thinking and aptitude for metaphor. They note that all humans have this ability to some degree, and speculate that there may be an evolutionary link between cross-modal (across senses) synthesis of experience, high-level perceptual thinking, and the human facility with language and abstraction.

Tuesday, April 22, 2003

"Silence is fatal", "Powerless to stop the spread", "Can we contain SARS", "Where did this deadly pneumonia come from?" and "Amorous worms reveal the effect of Chernobyl fallout on wildlife." In: New Scientist. 12 April 2003.

Not surprisingly, SARS is the big topic in science news magazines at the moment. SARS (severe acute respiratory syndrome) is currently believed to be caused by a coronavirus--a family of viruses that cause severe illnesses in animals, as well as colds and intestinal illness in humans. The closest matches to known viruses appear to be with avian infectious bronchitis and bovine coronavirus. An avian origin for the disease fits with reports that the first cases of SARS in Guangdong China were among bird handlers. Different coronaviruses swap genes freely, or random mutations can cause a virus to suddenly change tissue and host preference.

Somewhat encouragingly, it seems that the SARS virus is carried by large droplets that are coughed out--rather than the fine aerosol droplets that can carry flu virus for long distances. This means that infection only spreads by close contact with infected individuals, or by hand to mouth contact with something (doorknob, stair rail) that an infected individual has contaminated. So, frequent hand washing with soap is probably a more effective protection against SARS that wearing a paper surgical mask.

It seems that biggest reason SARS has spread so far and created such a stir is that the Chinese government, fearing economic repercussions, kept the outbreak a secret until it was too late to contain it. According to "New Scientist" WHO is currently working with the WTO to try to develop a plan for compensating countries facing economic loss as a result of reporting a possible outbreak of new, dangerous infectious diseases--in hopes of countering tendencies to secretiveness.

As for the article on amorous worms... Talk about a hook. How's this: "Worms contaminated by radioactivity from the Chernobyl nuclear accident have started having sex with each other instead of on their own"?

Apparently several species of lake-dwelling, sedimentary worms have switched to sexual, rather than asexual, reproduction as a result of the heavy radioactive contamination of the Chernobyl area. Theory is that sex promotes the spreading of any genes affording protection from radiation-induced damage.

Someone from my work sent this excellent link on risk communication, risk management and SARS:

Saturday, April 05, 2003

"A Summer Plague: Polio and its Survivors" by Tony Gould

"A Summer Plague" contains both a history of the polio epidemic and a series of biographical experiences of polio survivors. Biographical information includes the author (who contracted the disease in 1959, at age 20), FDR, rock musician Ian Drury, as well as others affected to greater or lesser degree. The overall focus is more on the social consequences of the disease than on the scientific aspects--though that focus includes controversies and conflicts among the scientific community, as well as between scientists and research-funding organizations. I found it fascinating to see the same kind of clashes of personalities and ambition among physician-scientists in the 1930ies and 1950ies as can be seen in laboratories today--and which has been seen at the cutting edge of medical research since the days of Pasteur, Koch, and Lister.

As an endemic disease, polio is believed to date back over three thousand years. An Egyptian stele, dating from the 18th dynasty (1580-1350 BC) depicts a man with a withered leg--characteristic of polio's lingering effects. It is believed that for most of human history the disease lurked in unhygienic conditions, probably infecting most infants at such an early age that they either died or recovered completely.

Not until modern times, when most people in the developed world escaped early infection, did the disease begin to roll through populations on a massive scale, leaving a trail of paralyzed children and adults. In the absence of any clear understanding of how to control the spread of polio, the New York epidemic of 1916 was dealt with by strict quarantine, close scrutiny of immigrants (Italians, in particular), and rigidly-enforced sanitation laws. There were stories of children being taken from their homes to hospital at gunpoint, because of suspected infection. Cats and dogs, erroneously suspected of carrying the disease, were rounded up and put down.

Polio was known to be a viral disease as early as 1908, but a century later a cure has yet to be developed, and a safe and reliable vaccine wasn't readily available until the late 1950ies. Early virologists were hamstrung by a number of incorrect beliefs about the virus--perhaps the most serious being a stubborn insistence that it was a respiratory, rather than enteric disease, which traveled directly from the nasal passages to the nervous tissue. Because of this belief, vaccination to produce blood-borne immunity was considered by some prominent scientists to be pointless. Picric acid and alum nasal sprays were tried as a preventative in the mid 1930ies, but succeeded only in permanently destroying the sense of smell for some patients. Results of contemporaneous attempts to develop a vaccine, despite doubts about the approach, ranged from ineffective to dangerous.

In 1940, the larger-than-life and ever controversial Sister Kenny arrived in the U.S. from Australia, bringing along her unorthodox (at the time) system of treating polio patients by getting their paralyzed muscles moving as soon as possible. Patients loved her; doctors hated the assurance with which she ridiculed the standard treatment of immobilizing paralyzed patients in splints or casts.

I'm afraid the book's overdue, and can't be renewed anymore, so it has to go back to the library today. Or else I'd write more about the famous Salk/Sabin rivalry and the controversy over live versus killed vaccine. I'll just date myself by mentioning some of my earliest memories of walking over to the local elementary school with my parents to receive my sugar cubes of vaccine. Polio is not quite dead in the wild yet; may it soon be so.

Tuesday, April 01, 2003

"Demon-Haunted Brain" by Michael Shermer. Scientific American online, February 10, 2003

"If the brain mediates all experience, then paranormal phenonmena are nothing more than neuronal events....The fate of the paranormal and the supernatural is to be subsumed into the normal and the natural....In reality, all experience is mediated by the brain."

Well, yeah, of course, but what's interesting is that experiments are beginning to pin down regions of the brain and types of stimuli capable of inducing perceptual alterations that might be interpreted (presumably depending upon one's cultural context) as anything from out-of-body experiences, to alien abductions, to persecution by spirits or incubi and succubi. For example, neuroscientist Michael Persinger can induce abnormal perceptions by subjecting experimental subjects to stimulation of their temporal lobes by "patterns of magnetic fields." A Swiss neuroscientist induced out-of-the-body experiences in an epileptic woman through electrical stimulation of the right angular gyrus in the temporal lobe. Other studies have looked at brain scans of Buddist monks and Franciscan nuns deep in prayer, and found "strikingly low" activity in the posterior superior parietal lobe. The study authors have named this area of the brain the "orientation association area" (OAA). The OAA apparently provides the sense of distinction between self and nonself--allowing a sense of orientation in physical space. Without it, lines blur: nuns may feel the presence of God, alien abductees believe they have been floated out of their beds and probed...