Genuine pleasure

If an artist had to paint a picture of genuine pleasure, what would it look like? I can imagine a universe of things that give pleasure to humans ranging from the mundane to the sublime. I think it would make for a great collaborative artwork for various individuals to render in symbols what gives them true enjoyment of life. But in science, what is genuine pleasure as it registers in our brain? Is it desiring something and getting it? Is it even possible to want something but not enjoy it when you get it?

Once upon a time, brain science used to think that the “pleasure circuit” is composed of the same switches as the reward circuit. You do something that makes you feel rewarded and you feel pleasure. Seemed simple enough. But most recent studies showed that this may not be the complete picture. This was explained by Morten L. Kringelbach and Kent C. Berridge in the August 2012 issue of the Scientific American as they gave the historical highlight of experiments on pleasure and the brain. I was surprised at what their own studies have revealed about pleasure so far.

Kringelbach and Berridge cited studies by Robert Heath in the 1950s that have shown that when electrodes were placed on certain brain parts of patients with severe neurological conditions and they were given the freedom to “zap” themselves, they would do so. One patient even reported to have zapped himself about 1,500 times within three hours because it gave him feelings of “pleasure, alertness and warmth (goodwill).” But they also wrote that the first real look into brain parts that light up when experiencing pleasure were from studies by scientists from McGill University namely James Olds and Peter Milner. They experimented on rats who if they choose to zap themselves, they would have access to food. It turned out that the rats zapped themselves so many times and not necessarily because it led to food. This led Olds and Milner to declare that they seemed to have zeroed in on a circuitry for reward which they identified to be composed of the following brain parts: nucleus accumbens, cingulated cortex.

However, the research of the authors of the Scientific American piece discovered that there are other parts of the brain which seem to have as much to do with the pleasure circuitry. What is even more intriguing is that feeling rewarded makes the brain want something over and over again but not necessarily like or enjoy it. Their experimental design was simple and elegant. Instead of “zapping” as proof of enjoyment, they looked for gestures in the rats’ faces (licking of lips) when they experience a sweet treat to make sure it is really enjoyment. They then discovered that while the reward circuit plays a role in pleasure, there are other subregions involved, namely the medial shell and the ventral pallidum. These parts seem to enlarge the sense of pleasure with the help of chemicals naturally found in the brain like enkephalin, anandamide and orexin.  

Even more important is they found that pleasure to be authentic needs to be mediated by another brain part located in our “judgement region,” the orbitofrontal cortex, the midanterior site in particular. It is that part that seems to tell us “it is good... better... best... up to this point only... after this, you don’t really enjoy it as much anymore.” That makes a lot of sense so that you don’t obsess about the same thing over and over again and limit yourself or give too much power to that “thing” over you. And that is what addiction is — you get numb to that check that tells you when you have had enough of something so that you continue to crave what no longer gives you any pleasure. Worse, addiction makes you crave something in increasing amounts. They also cited another experiment which they also repeated with modifications that showed that even when dopamine (the chemical released by the brain that makes you feel rewarded) is increased, the reward is sought (sweets) but the enjoyment (licking of mouth) does not necessarily increase anymore.

Genuine pleasure is experienced, even in passing, as a lightness of being. But this lightness apparently is the result of a complex circuitry of our brains that not only depends on feeling rewarded but also feeling contented. It is indeed my pleasure this week to get to know the circuitry that can tell what is merely “a lot” from being “full.” May our minds always work to insist on the difference.

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