In the psychological phenomenon known as "synesthesia," individuals' sensory systems are a bit more intertwined than usual. Some people, for example, report seeing colors when musical notes are played.

One of the most common forms is grapheme-color synesthesia, in which letters or numbers (collectively called "graphemes") are highlighted with particular colors. Although synesthesia has been well documented, it is unknown whether these experiences, reported as vivid and realistic, are actually being perceived or if they are a byproduct of some other psychological mechanism such as memory.

New research published in the June issue of Psychological Science, a journal of the Association for Psychological Science, sheds some light on the veracity of these perceptions.

Danko Nikolic, a researcher from the Max Planck Institute for Brain Research in Frankfurt, Germany, and his colleagues relied on a variation of a classic psychological method known as the Stroop task to test this. In this task, participants must name the color of the font that a color word is printed in. For example, if the word "blue" was printed in red ink, the participant would say "red" - a moderately difficult task that requires some mental gymnastics.

To understand Nikolic's version of the experiment, a rudimentary understanding of color perception is required: When anyone views a particular color, specific neurons in the visual cortex area of our brain are activated. These specific neurons will deactivate, however, if a color from the opposite end of the spectrum is presented. So, any neuron activated when the color blue is present will deactivate when it's exact opposite, yellow, comes into the visual field.

The public generally believes that poor lifestyle choices, faulty genes and infectious agents are the major factors that give rise to illness. Here's the rest of the story.

Lowering cholesterol with statins may slightly increase the risk of cancer, a study suggests.

It is not clear whether the cancer cases are caused by the drugs, or are a consequence of the low levels of "bad" LDL cholesterol produced by taking them.

The use of antidepressants and other mind-altering drugs among schoolchildren has more than quadrupled in the last decade, it is revealed today.

New figures show that GPs are prescribing pills in record numbers to combat stress, violent behaviour and even tiredness.

A recall of canned meat products and dog food made at a Georgia plant due to botulism fears could involve tens of millions of cans that pose an urgent public health threat, U.S. officials said on Monday.

U.S. food regulators appealed to consumers and retailers to find and dispose of the cans.

Two people in Texas and two others in Indiana remain seriously ill and hospitalized with botulism poisoning associated with eating Castleberry's Hot Dog Chili Sauce, officials said.

WASHINGTON/LONDON - Lowering cholesterol as much as possible may reduce the risk of heart disease, but with a price: taking it too low could raise the risk of cancer, U.S. researchers reported on Tuesday.

BOSTON - People who drank one or more diet sodas each day developed the same risks for heart disease as those who downed sugary regular soda, a large but inconclusive study found. The results surprised the researchers who expected to see a difference between regular and diet soda drinkers.

Pregnant and breastfeeding women and children under 6 should avoid fish high in mercury -- seafood still part of a healthy diet

A quarter of adult New Yorkers have elevated blood mercury levels, according to survey results released today by the Health Department, and the elevations are closely tied to fish consumption. Asian and higher-income New Yorkers eat more fish, and have higher average mercury levels, than others both locally and nationally. These mercury levels pose little if any health risk for most adults, but may increase the risk of cognitive delays for children whose mothers had very high mercury levels during pregnancy.

Major Findings on Blood Mercury Levels from NYC-HANES

Today's findings are the latest presented from New York City's Health and Nutrition Examination Survey (NYC-HANES), the first such survey ever conducted by a U.S. city. It's possible that other cities have similarly high levels, or higher ones, but haven't yet documented them. Because mercury is a concern for the health of newborns, recommendations on mercury exposure are most important for pregnant and breastfeeding women.

The woman's condition, known as prosopamnesia, is extremely rare and has only been found in a handful of people around the world, according to University of Queensland cognitive neuroscientist Professor Jason Mattingley.

"For many years, scientists have been interested in how people learn to recognise new faces, and people who have difficulty with faces often have trouble interacting in social settings," he said.

The woman - whose identity remains protected - presented herself to researchers after experiencing social embarrassment when she found she was unable to recognise colleagues, people to whom she had already been introduced.

The research, in collaboration with colleagues at Macquarie and La Trobe universities, is published in this month's edition of Current Biology. The work suggests the woman's "disability" might lie in her inability to encode or recognise new faces, rather than her ability to perceive them.

"She reports relying heavily on featural cues such as hair colour and style, eyeglasses, and eyebrows to recognise new acquaintances," Professor Mattingley said.

On a battery of standard face-recognition tests, the woman consistently registered scores that indicated her ability to recognise new faces was severely impaired.

This is my 113th and final Age of Autism column. United Press International, which has been the hospitable home for this series, is restructuring, and I'm off to adventures as yet unknown -- although I intend to keep my focus on autism and related issues.

Why? Because it is the story of a lifetime.