Overwhelming feelings of wanting and liking.
The brain divides wanting and liking into separate circuits for the same sweet reward. Natural heroin-like chemicals (opioids) in a few brain "pleasure hot spots" make individuals want to eat more of a tasty sweet food, and make them like its sweet taste more when they eat it. The same thing happens with addictions to drugs, sex, gambling, and other pursuits involving "brain reward" circuits.
Researchers Kyle Smith and Kent Berridge show that two different brain circuits carry out the wanting and liking for the sweet reward, even when both are triggered in the same brain pleasure hot spots. "We typically want what we like, and like what we want," Smith explains, "but these results suggest that wanting and liking are processed by distinct brain circuits and may not always go hand-in-hand." Adds Berridge, "The brain seems to be more stingy with mechanisms for pleasure than for desire."
A single looping circuit between hot spots always was found to be activated by stimuli that cause pleasure liking. On the other hand, a different outgoing circuit from nucleus accumbens appear to cause the wanting by going to the hypothalamus instead.
The findings suggest that wanting and liking for tasty treats either can change together or separately, depending on which brain circuits are involved. For example, various eating disorders might involve different activation patterns in the two brain circuits, possibly dissociating wanting from liking in some cases but not in others.
"It's relatively hard for a brain to generate pleasure because it needs to activate different opioid sites together to make you like something more," Berridge concludes. "It's easier to activate desire because a brain has several 'wanting' pathways available for the task. Sometimes, a brain will like the rewards it wants but, other times, it just wants them."
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|Title Annotation:||YOUR LIFE; how our brains affect our human tendencies|
|Publication:||USA Today (Magazine)|
|Article Type:||Brief article|
|Date:||Jul 1, 2007|
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