Questão 84 da UFG 2006 (inglês)

NEUROSCIENCE

NO MORE...PLEASE!

A chocolate orgy for science’s sake.

How does your brain know when you’ve had too much of a good thing? Dana Small, a cognitive neuroscientist at Northwestern University’s School of Medicine in Chicago, decided to look into it by feeding people chocolate. She stood in the hallway of her department and recruited nine self-proclaimed cocoa-bean lovers, hooked them up to MRI machines, gave them chocolate, and then measured blood flow in their brains while they ate. Between bites, they were asked two questions: “Do you want another piece?” and “On a scale of minus-10 to plus-10, how much did you like the last piece?”

Of course, in the time the volunteers’ euphoria over tasting the confection turned to satiation, and, as it did, Small saw changes in their brain activity. When the subjects ate chocolate and enjoyed it, a region associated with mood – the medial part of the orbital frontal cortex – was active. But as they began to feel satiated, blood stopped flowing to that area and increased in another region probably responsible for the decision to stop eating – the adjacent lateral orbital frontal cortex.

Such images will help scientists better understand how addiction causes the brain’s normal response to a good thing to go awry. But the research also yielded a curious, unexpected result: Women ate twice as much chocolate as men before getting their fill. And while men stopped eating because they began to find the chocolate unpleasant, women stopped only when their bellies were stuffed. During the course of the study, Small also discovered another interesting fact: People of Asian descent tended to be satisfied after eating only one or two pieces of chocolate. Non-Asians, on the other hand, practically gorged themselves.

Vocabulário
to go awry: sair do curso normal
gorged themselves: empanturraram-se