Roast dinosaur off the menu?
Giant meteorite impact 65 million years ago may not have set the world on
fire.
03 December 2003
PHILIP BALL

New evidence questions the idea that a meteorite impact thought to have
wiped out the dinosaurs triggered worldwide wildfires.

A crater about 180 kilometers wide attests to an asteroid having hit Earth
at Chicxulub on the Yucatan Peninsula in Mexico 65 million years ago. But
even about 2,000 km from here there were no big fires, claim Claire Belcher
of Royal Holloway College in London, UK and her colleagues1. So there can't
have been global conflagrations, conclude the researchers.

The group found no charcoal in sedimentary rocks laid down at the time - the
end of the Cretaceous period when 85 per cent of all species seem to have
become extinct. Other geologists have argued that soot in similar rocks
elsewhere is a sign that the meteorite released enough heat to spark fires
everywhere.

Traces of the impact have been found in sediments around the world. Rocks
from the Cretaceous-Tertiary or K-T boundary contain a sprinkling of the
element iridium, believed to have been carried by the meteorite. They are
also peppered with tiny glass-like blobs, the frozen remains of molten rock
flung high into the air at the impact site.

Read the rest at Nature
http://www.nature.com/nsu/031201/031201-3.html

Jokes activate same brain region as cocaine
Humour tickles drug centre that gives hedonistic high
04 December 2003
HELEN PEARSON

There's truth in the maxim 'laughter is a drug'. A comic cartoon fired up
the same brain centre as a shot of cocaine, researchers are reporting.

A team at Stanford University in California asked lab mates, spouses and
friends to select the wittiest newspaper cartoons from a portfolio. They
showed the winning array to 16 volunteers while peering inside their heads
by functional magnetic resonance imaging (fMRI).

The cartoons activated the same reward circuits in the brain that are
tickled by cocaine, money or a pretty face, the neuroscientists found. One
brain region in particular, the nucleus accumbens, lit up seconds after a
rib-tickler but remained listless after a lacklustre cartoon.

The nucleus accumbens is awash with the feelgood chemical dopamine. The
region's buzz may explain the euphoria that follows a good joke, the team
suggests. "Intuitively, it makes sense," agrees Bill Kelley, who studies
humour at Dartmouth College in Hanover, New Hampshire.

Earlier investigations found that humour triggers brain regions that work
out a joke's language and meaning, or those that control smiling and
laughter. Kelley, for example, has studied people's brains while they
watched episodes of television comedies Seinfeld and The Simpsons. "It's
surprising it's not consistent," he says.

Read the rest at Nature
http://www.nature.com/nsu/031201/031201-5.html

Comment:
Although humour, like most emotions, are entirely abstract in nature, the
subject still experiences some form of accompanying "real"
sensations.  This
offers at least some clue as to how these evolved.

Posted by
Robert Karl Stonjek.
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